Merge PR #1035

37 files changed, 3092 insertions, 1226 deletions

diff --git a/.gitignore b/.gitignore
index 23f76e8a..cf1c1a40 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,7 @@
 /config.*
 /src/luarocks/core/hardcoded.lua
 /testrun/*
+/lua_install
 # Stuff that pops up during development but shouldn't be in the repo (helps clean up `git status`)
 /build
 /build-binary
@@ -15,4 +16,5 @@
 /lua
 /lua_modules
 /luarocks
+/luarocks-admin
 /.luarocks
diff --git a/spec/which_spec.lua b/spec/which_spec.lua
index d5bcfab9..79b9ef7e 100644
--- a/spec/which_spec.lua
+++ b/spec/which_spec.lua
@@ -22,7 +22,7 @@ describe("LuaRocks which tests #integration", function()
 
    it("fails on missing arguments", function()
       local output = run.luarocks("which")
-      assert.match("Missing module name", output, 1, true)
+      assert.match("missing argument 'modname'", output, 1, true)
    end)
 
    it("finds modules found in package.path", function()
diff --git a/src/bin/luarocks b/src/bin/luarocks
index d982530c..56caaa60 100755
--- a/src/bin/luarocks
+++ b/src/bin/luarocks
@@ -9,7 +9,6 @@ local cmd = require("luarocks.cmd")
 local description = "LuaRocks main command-line interface"
 
 local commands = {
-   help = "luarocks.cmd.help",
    init = "luarocks.cmd.init",
    pack = "luarocks.cmd.pack",
    unpack = "luarocks.cmd.unpack",
diff --git a/src/bin/luarocks-admin b/src/bin/luarocks-admin
index 71e17b55..4a85e45b 100755
--- a/src/bin/luarocks-admin
+++ b/src/bin/luarocks-admin
@@ -9,7 +9,6 @@ local cmd = require("luarocks.cmd")
 local description = "LuaRocks repository administration interface"
 
 local commands = {
-   help = "luarocks.cmd.help",
    make_manifest = "luarocks.admin.cmd.make_manifest",
    add = "luarocks.admin.cmd.add",
    remove = "luarocks.admin.cmd.remove",
diff --git a/src/luarocks/admin/cmd/add.lua b/src/luarocks/admin/cmd/add.lua
index 19990b3c..5011c680 100644
--- a/src/luarocks/admin/cmd/add.lua
+++ b/src/luarocks/admin/cmd/add.lua
@@ -11,20 +11,20 @@ local fs = require("luarocks.fs")
 local cache = require("luarocks.admin.cache")
 local index = require("luarocks.admin.index")
 
-add.help_summary = "Add a rock or rockspec to a rocks server."
-add.help_arguments = "[--server=<server>] [--no-refresh] {<rockspec>|<rock>...}"
-add.help = [[
-Arguments are local files, which may be rockspecs or rocks.
-The flag --server indicates which server to use.
-If not given, the default server set in the upload_server variable
-from the configuration file is used instead.
-
---no-refresh  The local cache should not be refreshed
-              prior to generation of the updated manifest.
---index       Produce an index.html file for the manifest.
-              This flag is automatically set if an index.html
-              file already exists.
-]]
+function add.add_to_parser(parser)
+   local cmd = parser:command("add", "Add a rock or rockspec to a rocks server.", util.see_also())
+
+   cmd:argument("rock", "A local rockspec or rock file.")
+      :args("+")
+
+   cmd:option("--server", "The server to use. If not given, the default server "..
+      "set in the upload_server variable from the configuration file is used instead.")
+      :target("add_server")
+   cmd:flag("--no-refresh", "Do not refresh the local cache prior to "..
+      "generation of the updated manifest.")
+   cmd:flag("--index", "Produce an index.html file for the manifest. This "..
+      "flag is automatically set if an index.html file already exists.")
+end
 
 local function zip_manifests()
    for ver in util.lua_versions() do
@@ -124,14 +124,10 @@ local function add_files_to_server(refresh, rockfiles, server, upload_server, do
    return fs.execute(cmd)
 end
 
-function add.command(flags, ...)
-   local files = {...}
-   if #files < 1 then
-      return nil, "Argument missing. "..util.see_help("add", "luarocks-admin")
-   end
-   local server, server_table = cache.get_upload_server(flags["server"])
+function add.command(args)
+   local server, server_table = cache.get_upload_server(args.add_server or args.server)
    if not server then return nil, server_table end
-   return add_files_to_server(not flags["no-refresh"], files, server, server_table, flags["index"])
+   return add_files_to_server(not args.no_refresh, args.rock, server, server_table, args.index)
 end
 
 
diff --git a/src/luarocks/admin/cmd/make_manifest.lua b/src/luarocks/admin/cmd/make_manifest.lua
index f0b64135..ab940f9e 100644
--- a/src/luarocks/admin/cmd/make_manifest.lua
+++ b/src/luarocks/admin/cmd/make_manifest.lua
@@ -11,36 +11,36 @@ local deps = require("luarocks.deps")
 local fs = require("luarocks.fs")
 local dir = require("luarocks.dir")
 
-make_manifest.help_summary = "Compile a manifest file for a repository."
+function make_manifest.add_to_parser(parser)
+   local cmd = parser:command("make_manifest", "Compile a manifest file for a repository.", util.see_also())
+   parser:command("make-manifest"):hidden(true):action(function(args) args.command = "make_manifest" end)
 
-make_manifest.help = [[
-<argument>, if given, is a local repository pathname.
+   cmd:argument("repository", "Local repository pathname.")
+      :args("?")
 
---local-tree  If given, do not write versioned versions of the manifest file.
-              Use this when rebuilding the manifest of a local rocks tree.
-]]
+   cmd:flag("--local-tree", "If given, do not write versioned versions of the manifest file.\n"..
+      "Use this when rebuilding the manifest of a local rocks tree.")
+   util.deps_mode_option(cmd)
+end
 
 --- Driver function for "make_manifest" command.
--- @param repo string or nil: Pathname of a local repository. If not given,
--- the default local repository configured as cfg.rocks_dir is used.
 -- @return boolean or (nil, string): True if manifest was generated,
 -- or nil and an error message.
-function make_manifest.command(flags, repo)
-   assert(type(repo) == "string" or not repo)
-   repo = repo or cfg.rocks_dir
+function make_manifest.command(args)
+   local repo = args.repository or cfg.rocks_dir
   
    util.printout("Making manifest for "..repo)
    
-   if repo:match("/lib/luarocks") and not flags["local-tree"] then
+   if repo:match("/lib/luarocks") and not args.local_tree then
       util.warning("This looks like a local rocks tree, but you did not pass --local-tree.")
    end
    
-   local ok, err = writer.make_manifest(repo, deps.get_deps_mode(flags), not flags["local-tree"])
-   if ok and not flags["local-tree"] then
+   local ok, err = writer.make_manifest(repo, deps.get_deps_mode(args), not args.local_tree)
+   if ok and not args.local_tree then
       util.printout("Generating index.html for "..repo)
       index.make_index(repo)
    end
-   if flags["local-tree"] then
+   if args.local_tree then
       for luaver in util.lua_versions() do
          fs.delete(dir.path(repo, "manifest-"..luaver))
       end
diff --git a/src/luarocks/admin/cmd/refresh_cache.lua b/src/luarocks/admin/cmd/refresh_cache.lua
index 3ffe56d9..40c9ff09 100644
--- a/src/luarocks/admin/cmd/refresh_cache.lua
+++ b/src/luarocks/admin/cmd/refresh_cache.lua
@@ -3,18 +3,20 @@
 local refresh_cache = {}
 
 local cfg = require("luarocks.core.cfg")
+local util = require("luarocks.util")
 local cache = require("luarocks.admin.cache")
 
-refresh_cache.help_summary = "Refresh local cache of a remote rocks server."
-refresh_cache.help_arguments = "[--from=<server>]"
-refresh_cache.help = [[
-The flag --from indicates which server to use.
-If not given, the default server set in the upload_server variable
-from the configuration file is used instead.
-]]
+function refresh_cache.add_to_parser(parser)
+   local cmd = parser:command("refresh_cache", "Refresh local cache of a remote rocks server.", util.see_also())
+   parser:command("refresh-cache"):hidden(true):action(function(args) args.command = "refresh_cache" end)
 
-function refresh_cache.command(flags)
-   local server, upload_server = cache.get_upload_server(flags["server"])
+   cmd:option("--from", "The server to use. If not given, the default server "..
+      "set in the upload_server variable from the configuration file is used instead.")
+      :argname("<server>")
+end
+
+function refresh_cache.command(args)
+   local server, upload_server = cache.get_upload_server(args.server)
    if not server then return nil, upload_server end
    local download_url = cache.get_server_urls(server, upload_server)
    
diff --git a/src/luarocks/admin/cmd/remove.lua b/src/luarocks/admin/cmd/remove.lua
index f005c83c..de58f7a3 100644
--- a/src/luarocks/admin/cmd/remove.lua
+++ b/src/luarocks/admin/cmd/remove.lua
@@ -11,16 +11,17 @@ local fs = require("luarocks.fs")
 local cache = require("luarocks.admin.cache")
 local index = require("luarocks.admin.index")
 
-admin_remove.help_summary = "Remove a rock or rockspec from a rocks server."
-admin_remove.help_arguments = "[--server=<server>] [--no-refresh] {<rockspec>|<rock>...}"
-admin_remove.help = [[
-Arguments are local files, which may be rockspecs or rocks.
-The flag --server indicates which server to use.
-If not given, the default server set in the upload_server variable
-from the configuration file is used instead.
-The flag --no-refresh indicates the local cache should not be refreshed
-prior to generation of the updated manifest.
-]]
+function admin_remove.add_to_parser(parser)
+   local cmd = parser:command("remove", "Remove a rock or rockspec from a rocks server.", util.see_also())
+
+   cmd:argument("rock", "A local rockspec or rock file.")
+      :args("+")
+
+   cmd:option("--server", "The server to use. If not given, the default server "..
+      "set in the upload_server variable from the configuration file is used instead.")
+   cmd:flag("--no-refresh", "Do not refresh the local cache prior to "..
+      "generation of the updated manifest.")
+end
 
 local function remove_files_from_server(refresh, rockfiles, server, upload_server)
    assert(type(refresh) == "boolean" or not refresh)
@@ -76,14 +77,10 @@ local function remove_files_from_server(refresh, rockfiles, server, upload_serve
    return true
 end
 
-function admin_remove.command(flags, ...)
-   local files = {...}
-   if #files < 1 then
-      return nil, "Argument missing. "..util.see_help("remove", "luarocks-admin")
-   end
-   local server, server_table = cache.get_upload_server(flags["server"])
+function admin_remove.command(args)
+   local server, server_table = cache.get_upload_server(args.server)
    if not server then return nil, server_table end
-   return remove_files_from_server(not flags["no-refresh"], files, server, server_table)
+   return remove_files_from_server(not args.no_refresh, args.rock, server, server_table)
 end
 
 
diff --git a/src/luarocks/argparse.lua b/src/luarocks/argparse.lua
new file mode 100644
index 00000000..dc6cdb0d
--- /dev/null
+++ b/src/luarocks/argparse.lua
@@ -0,0 +1,2078 @@
+-- The MIT License (MIT)
+
+-- Copyright (c) 2013 - 2018 Peter Melnichenko
+--                      2019 Paul Ouellette
+
+-- Permission is hereby granted, free of charge, to any person obtaining a copy of
+-- this software and associated documentation files (the "Software"), to deal in
+-- the Software without restriction, including without limitation the rights to
+-- use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+-- the Software, and to permit persons to whom the Software is furnished to do so,
+-- subject to the following conditions:
+
+-- The above copyright notice and this permission notice shall be included in all
+-- copies or substantial portions of the Software.
+
+-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+-- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+-- FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+-- COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+-- IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+-- CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+local function deep_update(t1, t2)
+   for k, v in pairs(t2) do
+      if type(v) == "table" then
+         v = deep_update({}, v)
+      end
+
+      t1[k] = v
+   end
+
+   return t1
+end
+
+-- A property is a tuple {name, callback}.
+-- properties.args is number of properties that can be set as arguments
+-- when calling an object.
+local function class(prototype, properties, parent)
+   -- Class is the metatable of its instances.
+   local cl = {}
+   cl.__index = cl
+
+   if parent then
+      cl.__prototype = deep_update(deep_update({}, parent.__prototype), prototype)
+   else
+      cl.__prototype = prototype
+   end
+
+   if properties then
+      local names = {}
+
+      -- Create setter methods and fill set of property names.
+      for _, property in ipairs(properties) do
+         local name, callback = property[1], property[2]
+
+         cl[name] = function(self, value)
+            if not callback(self, value) then
+               self["_" .. name] = value
+            end
+
+            return self
+         end
+
+         names[name] = true
+      end
+
+      function cl.__call(self, ...)
+         -- When calling an object, if the first argument is a table,
+         -- interpret keys as property names, else delegate arguments
+         -- to corresponding setters in order.
+         if type((...)) == "table" then
+            for name, value in pairs((...)) do
+               if names[name] then
+                  self[name](self, value)
+               end
+            end
+         else
+            local nargs = select("#", ...)
+
+            for i, property in ipairs(properties) do
+               if i > nargs or i > properties.args then
+                  break
+               end
+
+               local arg = select(i, ...)
+
+               if arg ~= nil then
+                  self[property[1]](self, arg)
+               end
+            end
+         end
+
+         return self
+      end
+   end
+
+   -- If indexing class fails, fallback to its parent.
+   local class_metatable = {}
+   class_metatable.__index = parent
+
+   function class_metatable.__call(self, ...)
+      -- Calling a class returns its instance.
+      -- Arguments are delegated to the instance.
+      local object = deep_update({}, self.__prototype)
+      setmetatable(object, self)
+      return object(...)
+   end
+
+   return setmetatable(cl, class_metatable)
+end
+
+local function typecheck(name, types, value)
+   for _, type_ in ipairs(types) do
+      if type(value) == type_ then
+         return true
+      end
+   end
+
+   error(("bad property '%s' (%s expected, got %s)"):format(name, table.concat(types, " or "), type(value)))
+end
+
+local function typechecked(name, ...)
+   local types = {...}
+   return {name, function(_, value) typecheck(name, types, value) end}
+end
+
+local multiname = {"name", function(self, value)
+   typecheck("name", {"string"}, value)
+
+   for alias in value:gmatch("%S+") do
+      self._name = self._name or alias
+      table.insert(self._aliases, alias)
+   end
+
+   -- Do not set _name as with other properties.
+   return true
+end}
+
+local function parse_boundaries(str)
+   if tonumber(str) then
+      return tonumber(str), tonumber(str)
+   end
+
+   if str == "*" then
+      return 0, math.huge
+   end
+
+   if str == "+" then
+      return 1, math.huge
+   end
+
+   if str == "?" then
+      return 0, 1
+   end
+
+   if str:match "^%d+%-%d+$" then
+      local min, max = str:match "^(%d+)%-(%d+)$"
+      return tonumber(min), tonumber(max)
+   end
+
+   if str:match "^%d+%+$" then
+      local min = str:match "^(%d+)%+$"
+      return tonumber(min), math.huge
+   end
+end
+
+local function boundaries(name)
+   return {name, function(self, value)
+      typecheck(name, {"number", "string"}, value)
+
+      local min, max = parse_boundaries(value)
+
+      if not min then
+         error(("bad property '%s'"):format(name))
+      end
+
+      self["_min" .. name], self["_max" .. name] = min, max
+   end}
+end
+
+local actions = {}
+
+local option_action = {"action", function(_, value)
+   typecheck("action", {"function", "string"}, value)
+
+   if type(value) == "string" and not actions[value] then
+      error(("unknown action '%s'"):format(value))
+   end
+end}
+
+local option_init = {"init", function(self)
+   self._has_init = true
+end}
+
+local option_default = {"default", function(self, value)
+   if type(value) ~= "string" then
+      self._init = value
+      self._has_init = true
+      return true
+   end
+end}
+
+local add_help = {"add_help", function(self, value)
+   typecheck("add_help", {"boolean", "string", "table"}, value)
+
+   if self._help_option_idx then
+      table.remove(self._options, self._help_option_idx)
+      self._help_option_idx = nil
+   end
+
+   if value then
+      local help = self:flag()
+         :description "Show this help message and exit."
+         :action(function()
+            print(self:get_help())
+            os.exit(0)
+         end)
+
+      if value ~= true then
+         help = help(value)
+      end
+
+      if not help._name then
+         help "-h" "--help"
+      end
+
+      self._help_option_idx = #self._options
+   end
+end}
+
+local Parser = class({
+   _arguments = {},
+   _options = {},
+   _commands = {},
+   _mutexes = {},
+   _groups = {},
+   _require_command = true,
+   _handle_options = true
+}, {
+   args = 3,
+   typechecked("name", "string"),
+   typechecked("description", "string"),
+   typechecked("epilog", "string"),
+   typechecked("usage", "string"),
+   typechecked("help", "string"),
+   typechecked("require_command", "boolean"),
+   typechecked("handle_options", "boolean"),
+   typechecked("action", "function"),
+   typechecked("command_target", "string"),
+   typechecked("help_vertical_space", "number"),
+   typechecked("usage_margin", "number"),
+   typechecked("usage_max_width", "number"),
+   typechecked("help_usage_margin", "number"),
+   typechecked("help_description_margin", "number"),
+   typechecked("help_max_width", "number"),
+   add_help
+})
+
+local Command = class({
+   _aliases = {}
+}, {
+   args = 3,
+   multiname,
+   typechecked("description", "string"),
+   typechecked("epilog", "string"),
+   typechecked("summary", "string"),
+   typechecked("target", "string"),
+   typechecked("usage", "string"),
+   typechecked("help", "string"),
+   typechecked("require_command", "boolean"),
+   typechecked("handle_options", "boolean"),
+   typechecked("action", "function"),
+   typechecked("command_target", "string"),
+   typechecked("help_vertical_space", "number"),
+   typechecked("usage_margin", "number"),
+   typechecked("usage_max_width", "number"),
+   typechecked("help_usage_margin", "number"),
+   typechecked("help_description_margin", "number"),
+   typechecked("help_max_width", "number"),
+   typechecked("hidden", "boolean"),
+   add_help
+}, Parser)
+
+local Argument = class({
+   _minargs = 1,
+   _maxargs = 1,
+   _mincount = 1,
+   _maxcount = 1,
+   _defmode = "unused",
+   _show_default = true
+}, {
+   args = 5,
+   typechecked("name", "string"),
+   typechecked("description", "string"),
+   option_default,
+   typechecked("convert", "function", "table"),
+   boundaries("args"),
+   typechecked("target", "string"),
+   typechecked("defmode", "string"),
+   typechecked("show_default", "boolean"),
+   typechecked("argname", "string", "table"),
+   typechecked("choices", "table"),
+   typechecked("hidden", "boolean"),
+   option_action,
+   option_init
+})
+
+local Option = class({
+   _aliases = {},
+   _mincount = 0,
+   _overwrite = true
+}, {
+   args = 6,
+   multiname,
+   typechecked("description", "string"),
+   option_default,
+   typechecked("convert", "function", "table"),
+   boundaries("args"),
+   boundaries("count"),
+   typechecked("target", "string"),
+   typechecked("defmode", "string"),
+   typechecked("show_default", "boolean"),
+   typechecked("overwrite", "boolean"),
+   typechecked("argname", "string", "table"),
+   typechecked("choices", "table"),
+   typechecked("hidden", "boolean"),
+   option_action,
+   option_init
+}, Argument)
+
+function Parser:_inherit_property(name, default)
+   local element = self
+
+   while true do
+      local value = element["_" .. name]
+
+      if value ~= nil then
+         return value
+      end
+
+      if not element._parent then
+         return default
+      end
+
+      element = element._parent
+   end
+end
+
+function Argument:_get_argument_list()
+   local buf = {}
+   local i = 1
+
+   while i <= math.min(self._minargs, 3) do
+      local argname = self:_get_argname(i)
+
+      if self._default and self._defmode:find "a" then
+         argname = "[" .. argname .. "]"
+      end
+
+      table.insert(buf, argname)
+      i = i+1
+   end
+
+   while i <= math.min(self._maxargs, 3) do
+      table.insert(buf, "[" .. self:_get_argname(i) .. "]")
+      i = i+1
+
+      if self._maxargs == math.huge then
+         break
+      end
+   end
+
+   if i < self._maxargs then
+      table.insert(buf, "...")
+   end
+
+   return buf
+end
+
+function Argument:_get_usage()
+   local usage = table.concat(self:_get_argument_list(), " ")
+
+   if self._default and self._defmode:find "u" then
+      if self._maxargs > 1 or (self._minargs == 1 and not self._defmode:find "a") then
+         usage = "[" .. usage .. "]"
+      end
+   end
+
+   return usage
+end
+
+function actions.store_true(result, target)
+   result[target] = true
+end
+
+function actions.store_false(result, target)
+   result[target] = false
+end
+
+function actions.store(result, target, argument)
+   result[target] = argument
+end
+
+function actions.count(result, target, _, overwrite)
+   if not overwrite then
+      result[target] = result[target] + 1
+   end
+end
+
+function actions.append(result, target, argument, overwrite)
+   result[target] = result[target] or {}
+   table.insert(result[target], argument)
+
+   if overwrite then
+      table.remove(result[target], 1)
+   end
+end
+
+function actions.concat(result, target, arguments, overwrite)
+   if overwrite then
+      error("'concat' action can't handle too many invocations")
+   end
+
+   result[target] = result[target] or {}
+
+   for _, argument in ipairs(arguments) do
+      table.insert(result[target], argument)
+   end
+end
+
+function Argument:_get_action()
+   local action, init
+
+   if self._maxcount == 1 then
+      if self._maxargs == 0 then
+         action, init = "store_true", nil
+      else
+         action, init = "store", nil
+      end
+   else
+      if self._maxargs == 0 then
+         action, init = "count", 0
+      else
+         action, init = "append", {}
+      end
+   end
+
+   if self._action then
+      action = self._action
+   end
+
+   if self._has_init then
+      init = self._init
+   end
+
+   if type(action) == "string" then
+      action = actions[action]
+   end
+
+   return action, init
+end
+
+-- Returns placeholder for `narg`-th argument.
+function Argument:_get_argname(narg)
+   local argname = self._argname or self:_get_default_argname()
+
+   if type(argname) == "table" then
+      return argname[narg]
+   else
+      return argname
+   end
+end
+
+function Argument:_get_choices_list()
+   return "{" .. table.concat(self._choices, ",") .. "}"
+end
+
+function Argument:_get_default_argname()
+   if self._choices then
+      return self:_get_choices_list()
+   else
+      return "<" .. self._name .. ">"
+   end
+end
+
+function Option:_get_default_argname()
+   if self._choices then
+      return self:_get_choices_list()
+   else
+      return "<" .. self:_get_default_target() .. ">"
+   end
+end
+
+-- Returns labels to be shown in the help message.
+function Argument:_get_label_lines()
+   if self._choices then
+      return {self:_get_choices_list()}
+   else
+      return {self._name}
+   end
+end
+
+function Option:_get_label_lines()
+   local argument_list = self:_get_argument_list()
+
+   if #argument_list == 0 then
+      -- Don't put aliases for simple flags like `-h` on different lines.
+      return {table.concat(self._aliases, ", ")}
+   end
+
+   local longest_alias_length = -1
+
+   for _, alias in ipairs(self._aliases) do
+      longest_alias_length = math.max(longest_alias_length, #alias)
+   end
+
+   local argument_list_repr = table.concat(argument_list, " ")
+   local lines = {}
+
+   for i, alias in ipairs(self._aliases) do
+      local line = (" "):rep(longest_alias_length - #alias) .. alias .. " " .. argument_list_repr
+
+      if i ~= #self._aliases then
+         line = line .. ","
+      end
+
+      table.insert(lines, line)
+   end
+
+   return lines
+end
+
+function Command:_get_label_lines()
+   return {table.concat(self._aliases, ", ")}
+end
+
+function Argument:_get_description()
+   if self._default and self._show_default then
+      if self._description then
+         return ("%s (default: %s)"):format(self._description, self._default)
+      else
+         return ("default: %s"):format(self._default)
+      end
+   else
+      return self._description or ""
+   end
+end
+
+function Command:_get_description()
+   return self._summary or self._description or ""
+end
+
+function Option:_get_usage()
+   local usage = self:_get_argument_list()
+   table.insert(usage, 1, self._name)
+   usage = table.concat(usage, " ")
+
+   if self._mincount == 0 or self._default then
+      usage = "[" .. usage .. "]"
+   end
+
+   return usage
+end
+
+function Argument:_get_default_target()
+   return self._name
+end
+
+function Option:_get_default_target()
+   local res
+
+   for _, alias in ipairs(self._aliases) do
+      if alias:sub(1, 1) == alias:sub(2, 2) then
+         res = alias:sub(3)
+         break
+      end
+   end
+
+   res = res or self._name:sub(2)
+   return (res:gsub("-", "_"))
+end
+
+function Option:_is_vararg()
+   return self._maxargs ~= self._minargs
+end
+
+function Parser:_get_fullname(exclude_root)
+   local parent = self._parent
+   if exclude_root and not parent then
+      return ""
+   end
+   local buf = {self._name}
+
+   while parent do
+      if not exclude_root or parent._parent then
+         table.insert(buf, 1, parent._name)
+      end
+      parent = parent._parent
+   end
+
+   return table.concat(buf, " ")
+end
+
+function Parser:_update_charset(charset)
+   charset = charset or {}
+
+   for _, command in ipairs(self._commands) do
+      command:_update_charset(charset)
+   end
+
+   for _, option in ipairs(self._options) do
+      for _, alias in ipairs(option._aliases) do
+         charset[alias:sub(1, 1)] = true
+      end
+   end
+
+   return charset
+end
+
+function Parser:argument(...)
+   local argument = Argument(...)
+   table.insert(self._arguments, argument)
+   return argument
+end
+
+function Parser:option(...)
+   local option = Option(...)
+   table.insert(self._options, option)
+   return option
+end
+
+function Parser:flag(...)
+   return self:option():args(0)(...)
+end
+
+function Parser:command(...)
+   local command = Command():add_help(true)(...)
+   command._parent = self
+   table.insert(self._commands, command)
+   return command
+end
+
+function Parser:mutex(...)
+   local elements = {...}
+
+   for i, element in ipairs(elements) do
+      local mt = getmetatable(element)
+      assert(mt == Option or mt == Argument, ("bad argument #%d to 'mutex' (Option or Argument expected)"):format(i))
+   end
+
+   table.insert(self._mutexes, elements)
+   return self
+end
+
+function Parser:group(name, ...)
+   assert(type(name) == "string", ("bad argument #1 to 'group' (string expected, got %s)"):format(type(name)))
+
+   local group = {name = name, ...}
+
+   for i, element in ipairs(group) do
+      local mt = getmetatable(element)
+      assert(mt == Option or mt == Argument or mt == Command,
+         ("bad argument #%d to 'group' (Option or Argument or Command expected)"):format(i + 1))
+   end
+
+   table.insert(self._groups, group)
+   return self
+end
+
+local usage_welcome = "Usage: "
+
+function Parser:get_usage()
+   if self._usage then
+      return self._usage
+   end
+
+   local usage_margin = self:_inherit_property("usage_margin", #usage_welcome)
+   local max_usage_width = self:_inherit_property("usage_max_width", 70)
+   local lines = {usage_welcome .. self:_get_fullname()}
+
+   local function add(s)
+      if #lines[#lines]+1+#s <= max_usage_width then
+         lines[#lines] = lines[#lines] .. " " .. s
+      else
+         lines[#lines+1] = (" "):rep(usage_margin) .. s
+      end
+   end
+
+   -- Normally options are before positional arguments in usage messages.
+   -- However, vararg options should be after, because they can't be reliable used
+   -- before a positional argument.
+   -- Mutexes come into play, too, and are shown as soon as possible.
+   -- Overall, output usages in the following order:
+   -- 1. Mutexes that don't have positional arguments or vararg options.
+   -- 2. Options that are not in any mutexes and are not vararg.
+   -- 3. Positional arguments - on their own or as a part of a mutex.
+   -- 4. Remaining mutexes.
+   -- 5. Remaining options.
+
+   local elements_in_mutexes = {}
+   local added_elements = {}
+   local added_mutexes = {}
+   local argument_to_mutexes = {}
+
+   local function add_mutex(mutex, main_argument)
+      if added_mutexes[mutex] then
+         return
+      end
+
+      added_mutexes[mutex] = true
+      local buf = {}
+
+      for _, element in ipairs(mutex) do
+         if not element._hidden and not added_elements[element] then
+            if getmetatable(element) == Option or element == main_argument then
+               table.insert(buf, element:_get_usage())
+               added_elements[element] = true
+            end
+         end
+      end
+
+      if #buf == 1 then
+         add(buf[1])
+      elseif #buf > 1 then
+         add("(" .. table.concat(buf, " | ") .. ")")
+      end
+   end
+
+   local function add_element(element)
+      if not element._hidden and not added_elements[element] then
+         add(element:_get_usage())
+         added_elements[element] = true
+      end
+   end
+
+   for _, mutex in ipairs(self._mutexes) do
+      local is_vararg = false
+      local has_argument = false
+
+      for _, element in ipairs(mutex) do
+         if getmetatable(element) == Option then
+            if element:_is_vararg() then
+               is_vararg = true
+            end
+         else
+            has_argument = true
+            argument_to_mutexes[element] = argument_to_mutexes[element] or {}
+            table.insert(argument_to_mutexes[element], mutex)
+         end
+
+         elements_in_mutexes[element] = true
+      end
+
+      if not is_vararg and not has_argument then
+         add_mutex(mutex)
+      end
+   end
+
+   for _, option in ipairs(self._options) do
+      if not elements_in_mutexes[option] and not option:_is_vararg() then
+         add_element(option)
+      end
+   end
+
+   -- Add usages for positional arguments, together with one mutex containing them, if they are in a mutex.
+   for _, argument in ipairs(self._arguments) do
+      -- Pick a mutex as a part of which to show this argument, take the first one that's still available.
+      local mutex
+
+      if elements_in_mutexes[argument] then
+         for _, argument_mutex in ipairs(argument_to_mutexes[argument]) do
+            if not added_mutexes[argument_mutex] then
+               mutex = argument_mutex
+            end
+         end
+      end
+
+      if mutex then
+         add_mutex(mutex, argument)
+      else
+         add_element(argument)
+      end
+   end
+
+   for _, mutex in ipairs(self._mutexes) do
+      add_mutex(mutex)
+   end
+
+   for _, option in ipairs(self._options) do
+      add_element(option)
+   end
+
+   if #self._commands > 0 then
+      if self._require_command then
+         add("<command>")
+      else
+         add("[<command>]")
+      end
+
+      add("...")
+   end
+
+   return table.concat(lines, "\n")
+end
+
+local function split_lines(s)
+   if s == "" then
+      return {}
+   end
+
+   local lines = {}
+
+   if s:sub(-1) ~= "\n" then
+      s = s .. "\n"
+   end
+
+   for line in s:gmatch("([^\n]*)\n") do
+      table.insert(lines, line)
+   end
+
+   return lines
+end
+
+local function autowrap_line(line, max_length)
+   -- Algorithm for splitting lines is simple and greedy.
+   local result_lines = {}
+
+   -- Preserve original indentation of the line, put this at the beginning of each result line.
+   -- If the first word looks like a list marker ('*', '+', or '-'), add spaces so that starts
+   -- of the second and the following lines vertically align with the start of the second word.
+   local indentation = line:match("^ *")
+
+   if line:find("^ *[%*%+%-]") then
+      indentation = indentation .. " " .. line:match("^ *[%*%+%-]( *)")
+   end
+
+   -- Parts of the last line being assembled.
+   local line_parts = {}
+
+   -- Length of the current line.
+   local line_length = 0
+
+   -- Index of the next character to consider.
+   local index = 1
+
+   while true do
+      local word_start, word_finish, word = line:find("([^ ]+)", index)
+
+      if not word_start then
+         -- Ignore trailing spaces, if any.
+         break
+      end
+
+      local preceding_spaces = line:sub(index, word_start - 1)
+      index = word_finish + 1
+
+      if (#line_parts == 0) or (line_length + #preceding_spaces + #word <= max_length) then
+         -- Either this is the very first word or it fits as an addition to the current line, add it.
+         table.insert(line_parts, preceding_spaces) -- For the very first word this adds the indentation.
+         table.insert(line_parts, word)
+         line_length = line_length + #preceding_spaces + #word
+      else
+         -- Does not fit, finish current line and put the word into a new one.
+         table.insert(result_lines, table.concat(line_parts))
+         line_parts = {indentation, word}
+         line_length = #indentation + #word
+      end
+   end
+
+   if #line_parts > 0 then
+      table.insert(result_lines, table.concat(line_parts))
+   end
+
+   if #result_lines == 0 then
+      -- Preserve empty lines.
+      result_lines[1] = ""
+   end
+
+   return result_lines
+end
+
+-- Automatically wraps lines within given array,
+-- attempting to limit line length to `max_length`.
+-- Existing line splits are preserved.
+local function autowrap(lines, max_length)
+   local result_lines = {}
+
+   for _, line in ipairs(lines) do
+      local autowrapped_lines = autowrap_line(line, max_length)
+
+      for _, autowrapped_line in ipairs(autowrapped_lines) do
+         table.insert(result_lines, autowrapped_line)
+      end
+   end
+
+   return result_lines
+end
+
+function Parser:_get_element_help(element)
+   local label_lines = element:_get_label_lines()
+   local description_lines = split_lines(element:_get_description())
+
+   local result_lines = {}
+
+   -- All label lines should have the same length (except the last one, it has no comma).
+   -- If too long, start description after all the label lines.
+   -- Otherwise, combine label and description lines.
+
+   local usage_margin_len = self:_inherit_property("help_usage_margin", 3)
+   local usage_margin = (" "):rep(usage_margin_len)
+   local description_margin_len = self:_inherit_property("help_description_margin", 25)
+   local description_margin = (" "):rep(description_margin_len)
+
+   local help_max_width = self:_inherit_property("help_max_width")
+
+   if help_max_width then
+      local description_max_width = math.max(help_max_width - description_margin_len, 10)
+      description_lines = autowrap(description_lines, description_max_width)
+   end
+
+   if #label_lines[1] >= (description_margin_len - usage_margin_len) then
+      for _, label_line in ipairs(label_lines) do
+         table.insert(result_lines, usage_margin .. label_line)
+      end
+
+      for _, description_line in ipairs(description_lines) do
+         table.insert(result_lines, description_margin .. description_line)
+      end
+   else
+      for i = 1, math.max(#label_lines, #description_lines) do
+         local label_line = label_lines[i]
+         local description_line = description_lines[i]
+
+         local line = ""
+
+         if label_line then
+            line = usage_margin .. label_line
+         end
+
+         if description_line and description_line ~= "" then
+            line = line .. (" "):rep(description_margin_len - #line) .. description_line
+         end
+
+         table.insert(result_lines, line)
+      end
+   end
+
+   return table.concat(result_lines, "\n")
+end
+
+local function get_group_types(group)
+   local types = {}
+
+   for _, element in ipairs(group) do
+      types[getmetatable(element)] = true
+   end
+
+   return types
+end
+
+function Parser:_add_group_help(blocks, added_elements, label, elements)
+   local buf = {label}
+
+   for _, element in ipairs(elements) do
+      if not element._hidden and not added_elements[element] then
+         added_elements[element] = true
+         table.insert(buf, self:_get_element_help(element))
+      end
+   end
+
+   if #buf > 1 then
+      table.insert(blocks, table.concat(buf, ("\n"):rep(self:_inherit_property("help_vertical_space", 0) + 1)))
+   end
+end
+
+function Parser:get_help()
+   if self._help then
+      return self._help
+   end
+
+   local blocks = {self:get_usage()}
+
+   local help_max_width = self:_inherit_property("help_max_width")
+
+   if self._description then
+      local description = self._description
+
+      if help_max_width then
+         description = table.concat(autowrap(split_lines(description), help_max_width), "\n")
+      end
+
+      table.insert(blocks, description)
+   end
+
+   -- 1. Put groups containing arguments first, then other arguments.
+   -- 2. Put remaining groups containing options, then other options.
+   -- 3. Put remaining groups containing commands, then other commands.
+   -- Assume that an element can't be in several groups.
+   local groups_by_type = {
+      [Argument] = {},
+      [Option] = {},
+      [Command] = {}
+   }
+
+   for _, group in ipairs(self._groups) do
+      local group_types = get_group_types(group)
+
+      for _, mt in ipairs({Argument, Option, Command}) do
+         if group_types[mt] then
+            table.insert(groups_by_type[mt], group)
+            break
+         end
+      end
+   end
+
+   local default_groups = {
+      {name = "Arguments", type = Argument, elements = self._arguments},
+      {name = "Options", type = Option, elements = self._options},
+      {name = "Commands", type = Command, elements = self._commands}
+   }
+
+   local added_elements = {}
+
+   for _, default_group in ipairs(default_groups) do
+      local type_groups = groups_by_type[default_group.type]
+
+      for _, group in ipairs(type_groups) do
+         self:_add_group_help(blocks, added_elements, group.name .. ":", group)
+      end
+
+      local default_label = default_group.name .. ":"
+
+      if #type_groups > 0 then
+         default_label = "Other " .. default_label:gsub("^.", string.lower)
+      end
+
+      self:_add_group_help(blocks, added_elements, default_label, default_group.elements)
+   end
+
+   if self._epilog then
+      local epilog = self._epilog
+
+      if help_max_width then
+         epilog = table.concat(autowrap(split_lines(epilog), help_max_width), "\n")
+      end
+
+      table.insert(blocks, epilog)
+   end
+
+   return table.concat(blocks, "\n\n")
+end
+
+function Parser:add_help_command(value)
+   if value then
+      assert(type(value) == "string" or type(value) == "table",
+         ("bad argument #1 to 'add_help_command' (string or table expected, got %s)"):format(type(value)))
+   end
+
+   local help = self:command()
+      :description "Show help for commands."
+   help:argument "command"
+      :description "The command to show help for."
+      :args "?"
+      :action(function(_, _, cmd)
+         if not cmd then
+            print(self:get_help())
+            os.exit(0)
+         else
+            for _, command in ipairs(self._commands) do
+               for _, alias in ipairs(command._aliases) do
+                  if alias == cmd then
+                     print(command:get_help())
+                     os.exit(0)
+                  end
+               end
+            end
+         end
+         help:error(("unknown command '%s'"):format(cmd))
+      end)
+
+   if value then
+      help = help(value)
+   end
+
+   if not help._name then
+      help "help"
+   end
+
+   help._is_help_command = true
+   return self
+end
+
+function Parser:_is_shell_safe()
+   if self._basename then
+      if self._basename:find("[^%w_%-%+%.]") then
+         return false
+      end
+   else
+      for _, alias in ipairs(self._aliases) do
+         if alias:find("[^%w_%-%+%.]") then
+            return false
+         end
+      end
+   end
+   for _, option in ipairs(self._options) do
+      for _, alias in ipairs(option._aliases) do
+         if alias:find("[^%w_%-%+%.]") then
+            return false
+         end
+      end
+      if option._choices then
+         for _, choice in ipairs(option._choices) do
+            if choice:find("[%s'\"]") then
+               return false
+            end
+         end
+      end
+   end
+   for _, argument in ipairs(self._arguments) do
+      if argument._choices then
+         for _, choice in ipairs(argument._choices) do
+            if choice:find("[%s'\"]") then
+               return false
+            end
+         end
+      end
+   end
+   for _, command in ipairs(self._commands) do
+      if not command:_is_shell_safe() then
+         return false
+      end
+   end
+   return true
+end
+
+function Parser:add_complete(value)
+   if value then
+      assert(type(value) == "string" or type(value) == "table",
+         ("bad argument #1 to 'add_complete' (string or table expected, got %s)"):format(type(value)))
+   end
+
+   local complete = self:option()
+      :description "Output a shell completion script for the specified shell."
+      :args(1)
+      :choices {"bash", "zsh", "fish"}
+      :action(function(_, _, shell)
+         io.write(self["get_" .. shell .. "_complete"](self))
+         os.exit(0)
+      end)
+
+   if value then
+      complete = complete(value)
+   end
+
+   if not complete._name then
+      complete "--completion"
+   end
+
+   return self
+end
+
+function Parser:add_complete_command(value)
+   if value then
+      assert(type(value) == "string" or type(value) == "table",
+         ("bad argument #1 to 'add_complete_command' (string or table expected, got %s)"):format(type(value)))
+   end
+
+   local complete = self:command()
+      :description "Output a shell completion script."
+   complete:argument "shell"
+      :description "The shell to output a completion script for."
+      :choices {"bash", "zsh", "fish"}
+      :action(function(_, _, shell)
+         io.write(self["get_" .. shell .. "_complete"](self))
+         os.exit(0)
+      end)
+
+   if value then
+      complete = complete(value)
+   end
+
+   if not complete._name then
+      complete "completion"
+   end
+
+   return self
+end
+
+local function base_name(pathname)
+   return pathname:gsub("[/\\]*$", ""):match(".*[/\\]([^/\\]*)") or pathname
+end
+
+local function get_short_description(element)
+   local short = element:_get_description():match("^(.-)%.%s")
+   return short or element:_get_description():match("^(.-)%.?$")
+end
+
+function Parser:_get_options()
+   local options = {}
+   for _, option in ipairs(self._options) do
+      for _, alias in ipairs(option._aliases) do
+         table.insert(options, alias)
+      end
+   end
+   return table.concat(options, " ")
+end
+
+function Parser:_get_commands()
+   local commands = {}
+   for _, command in ipairs(self._commands) do
+      for _, alias in ipairs(command._aliases) do
+         table.insert(commands, alias)
+      end
+   end
+   return table.concat(commands, " ")
+end
+
+function Parser:_bash_option_args(buf, indent)
+   local opts = {}
+   for _, option in ipairs(self._options) do
+      if option._choices or option._minargs > 0 then
+         local compreply
+         if option._choices then
+            compreply = 'COMPREPLY=($(compgen -W "' .. table.concat(option._choices, " ") .. '" -- "$cur"))'
+         else
+            compreply = 'COMPREPLY=($(compgen -f -- "$cur"))'
+         end
+         table.insert(opts, (" "):rep(indent + 4) .. table.concat(option._aliases, "|") .. ")")
+         table.insert(opts, (" "):rep(indent + 8) .. compreply)
+         table.insert(opts, (" "):rep(indent + 8) .. "return 0")
+         table.insert(opts, (" "):rep(indent + 8) .. ";;")
+      end
+   end
+
+   if #opts > 0 then
+      table.insert(buf, (" "):rep(indent) .. 'case "$prev" in')
+      table.insert(buf, table.concat(opts, "\n"))
+      table.insert(buf, (" "):rep(indent) .. "esac\n")
+   end
+end
+
+function Parser:_bash_get_cmd(buf, indent)
+   if #self._commands == 0 then
+      return
+   end
+
+   table.insert(buf, (" "):rep(indent) .. 'args=("${args[@]:1}")')
+   table.insert(buf, (" "):rep(indent) .. 'for arg in "${args[@]}"; do')
+   table.insert(buf, (" "):rep(indent + 4) .. 'case "$arg" in')
+
+   for _, command in ipairs(self._commands) do
+      table.insert(buf, (" "):rep(indent + 8) .. table.concat(command._aliases, "|") .. ")")
+      if self._parent then
+         table.insert(buf, (" "):rep(indent + 12) .. 'cmd="$cmd ' .. command._name .. '"')
+      else
+         table.insert(buf, (" "):rep(indent + 12) .. 'cmd="' .. command._name .. '"')
+      end
+      table.insert(buf, (" "):rep(indent + 12) .. 'opts="$opts ' .. command:_get_options() .. '"')
+      command:_bash_get_cmd(buf, indent + 12)
+      table.insert(buf, (" "):rep(indent + 12) .. "break")
+      table.insert(buf, (" "):rep(indent + 12) .. ";;")
+   end
+
+   table.insert(buf, (" "):rep(indent + 4) .. "esac")
+   table.insert(buf, (" "):rep(indent) .. "done")
+end
+
+function Parser:_bash_cmd_completions(buf)
+   local cmd_buf = {}
+   if self._parent then
+      self:_bash_option_args(cmd_buf, 12)
+   end
+   if #self._commands > 0 then
+      table.insert(cmd_buf, (" "):rep(12) .. 'COMPREPLY=($(compgen -W "' .. self:_get_commands() .. '" -- "$cur"))')
+   elseif self._is_help_command then
+      table.insert(cmd_buf, (" "):rep(12)
+         .. 'COMPREPLY=($(compgen -W "'
+         .. self._parent:_get_commands()
+         .. '" -- "$cur"))')
+   end
+   if #cmd_buf > 0 then
+      table.insert(buf, (" "):rep(8) .. "'" .. self:_get_fullname(true) .. "')")
+      table.insert(buf, table.concat(cmd_buf, "\n"))
+      table.insert(buf, (" "):rep(12) .. ";;")
+   end
+
+   for _, command in ipairs(self._commands) do
+      command:_bash_cmd_completions(buf)
+   end
+end
+
+function Parser:get_bash_complete()
+   self._basename = base_name(self._name)
+   assert(self:_is_shell_safe())
+   local buf = {([[
+_%s() {
+    local IFS=$' \t\n'
+    local args cur prev cmd opts arg
+    args=("${COMP_WORDS[@]}")
+    cur="${COMP_WORDS[COMP_CWORD]}"
+    prev="${COMP_WORDS[COMP_CWORD-1]}"
+    opts="%s"
+]]):format(self._basename, self:_get_options())}
+
+   self:_bash_option_args(buf, 4)
+   self:_bash_get_cmd(buf, 4)
+   if #self._commands > 0 then
+      table.insert(buf, "")
+      table.insert(buf, (" "):rep(4) .. 'case "$cmd" in')
+      self:_bash_cmd_completions(buf)
+      table.insert(buf, (" "):rep(4) .. "esac\n")
+   end
+
+   table.insert(buf, ([=[
+    if [[ "$cur" = -* ]]; then
+        COMPREPLY=($(compgen -W "$opts" -- "$cur"))
+    fi
+}
+
+complete -F _%s -o bashdefault -o default %s
+]=]):format(self._basename, self._basename))
+
+   return table.concat(buf, "\n")
+end
+
+function Parser:_zsh_arguments(buf, cmd_name, indent)
+   if self._parent then
+      table.insert(buf, (" "):rep(indent) .. "options=(")
+      table.insert(buf, (" "):rep(indent + 2) .. "$options")
+   else
+      table.insert(buf, (" "):rep(indent) .. "local -a options=(")
+   end
+
+   for _, option in ipairs(self._options) do
+      local line = {}
+      if #option._aliases > 1 then
+         if option._maxcount > 1 then
+            table.insert(line, '"*"')
+         end
+         table.insert(line, "{" .. table.concat(option._aliases, ",") .. '}"')
+      else
+         table.insert(line, '"')
+         if option._maxcount > 1 then
+            table.insert(line, "*")
+         end
+         table.insert(line, option._name)
+      end
+      if option._description then
+         local description = get_short_description(option):gsub('["%]:`$]', "\\%0")
+         table.insert(line, "[" .. description .. "]")
+      end
+      if option._maxargs == math.huge then
+         table.insert(line, ":*")
+      end
+      if option._choices then
+         table.insert(line, ": :(" .. table.concat(option._choices, " ") .. ")")
+      elseif option._maxargs > 0 then
+         table.insert(line, ": :_files")
+      end
+      table.insert(line, '"')
+      table.insert(buf, (" "):rep(indent + 2) .. table.concat(line))
+   end
+
+   table.insert(buf, (" "):rep(indent) .. ")")
+   table.insert(buf, (" "):rep(indent) .. "_arguments -s -S \\")
+   table.insert(buf, (" "):rep(indent + 2) .. "$options \\")
+
+   if self._is_help_command then
+      table.insert(buf, (" "):rep(indent + 2) .. '": :(' .. self._parent:_get_commands() .. ')" \\')
+   else
+      for _, argument in ipairs(self._arguments) do
+         local spec
+         if argument._choices then
+            spec = ": :(" .. table.concat(argument._choices, " ") .. ")"
+         else
+            spec = ": :_files"
+         end
+         if argument._maxargs == math.huge then
+            table.insert(buf, (" "):rep(indent + 2) .. '"*' .. spec .. '" \\')
+            break
+         end
+         for _ = 1, argument._maxargs do
+            table.insert(buf, (" "):rep(indent + 2) .. '"' .. spec .. '" \\')
+         end
+      end
+
+      if #self._commands > 0 then
+         table.insert(buf, (" "):rep(indent + 2) .. '": :_' .. cmd_name .. '_cmds" \\')
+         table.insert(buf, (" "):rep(indent + 2) .. '"*:: :->args" \\')
+      end
+   end
+
+   table.insert(buf, (" "):rep(indent + 2) .. "&& return 0")
+end
+
+function Parser:_zsh_cmds(buf, cmd_name)
+   table.insert(buf, "\n_" .. cmd_name .. "_cmds() {")
+   table.insert(buf, "  local -a commands=(")
+
+   for _, command in ipairs(self._commands) do
+      local line = {}
+      if #command._aliases > 1 then
+         table.insert(line, "{" .. table.concat(command._aliases, ",") .. '}"')
+      else
+         table.insert(line, '"' .. command._name)
+      end
+      if command._description then
+         table.insert(line, ":" .. get_short_description(command):gsub('["`$]', "\\%0"))
+      end
+      table.insert(buf, "    " .. table.concat(line) .. '"')
+   end
+
+   table.insert(buf, '  )\n  _describe "command" commands\n}')
+end
+
+function Parser:_zsh_complete_help(buf, cmds_buf, cmd_name, indent)
+   if #self._commands == 0 then
+      return
+   end
+
+   self:_zsh_cmds(cmds_buf, cmd_name)
+   table.insert(buf, "\n" .. (" "):rep(indent) .. "case $words[1] in")
+
+   for _, command in ipairs(self._commands) do
+      local name = cmd_name .. "_" .. command._name
+      table.insert(buf, (" "):rep(indent + 2) .. table.concat(command._aliases, "|") .. ")")
+      command:_zsh_arguments(buf, name, indent + 4)
+      command:_zsh_complete_help(buf, cmds_buf, name, indent + 4)
+      table.insert(buf, (" "):rep(indent + 4) .. ";;\n")
+   end
+
+   table.insert(buf, (" "):rep(indent) .. "esac")
+end
+
+function Parser:get_zsh_complete()
+   self._basename = base_name(self._name)
+   assert(self:_is_shell_safe())
+   local buf = {("#compdef %s\n"):format(self._basename)}
+   local cmds_buf = {}
+   table.insert(buf, "_" .. self._basename .. "() {")
+   if #self._commands > 0 then
+      table.insert(buf, "  local context state state_descr line")
+      table.insert(buf, "  typeset -A opt_args\n")
+   end
+   self:_zsh_arguments(buf, self._basename, 2)
+   self:_zsh_complete_help(buf, cmds_buf, self._basename, 2)
+   table.insert(buf, "\n  return 1")
+   table.insert(buf, "}")
+
+   local result = table.concat(buf, "\n")
+   if #cmds_buf > 0 then
+      result = result .. "\n" .. table.concat(cmds_buf, "\n")
+   end
+   return result .. "\n\n_" .. self._basename .. "\n"
+end
+
+local function fish_escape(string)
+   return string:gsub("[\\']", "\\%0")
+end
+
+function Parser:_fish_get_cmd(buf, indent)
+   if #self._commands == 0 then
+      return
+   end
+
+   table.insert(buf, (" "):rep(indent) .. "set -e cmdline[1]")
+   table.insert(buf, (" "):rep(indent) .. "for arg in $cmdline")
+   table.insert(buf, (" "):rep(indent + 4) .. "switch $arg")
+
+   for _, command in ipairs(self._commands) do
+      table.insert(buf, (" "):rep(indent + 8) .. "case " .. table.concat(command._aliases, " "))
+      table.insert(buf, (" "):rep(indent + 12) .. "set cmd $cmd " .. command._name)
+      command:_fish_get_cmd(buf, indent + 12)
+      table.insert(buf, (" "):rep(indent + 12) .. "break")
+   end
+
+   table.insert(buf, (" "):rep(indent + 4) .. "end")
+   table.insert(buf, (" "):rep(indent) .. "end")
+end
+
+function Parser:_fish_complete_help(buf, basename)
+   local prefix = "complete -c " .. basename
+   table.insert(buf, "")
+
+   for _, command in ipairs(self._commands) do
+      local aliases = table.concat(command._aliases, " ")
+      local line
+      if self._parent then
+         line = ("%s -n '__fish_%s_using_command %s' -xa '%s'")
+            :format(prefix, basename, self:_get_fullname(true), aliases)
+      else
+         line = ("%s -n '__fish_%s_using_command' -xa '%s'"):format(prefix, basename, aliases)
+      end
+      if command._description then
+         line = ("%s -d '%s'"):format(line, fish_escape(get_short_description(command)))
+      end
+      table.insert(buf, line)
+   end
+
+   if self._is_help_command then
+      local line = ("%s -n '__fish_%s_using_command %s' -xa '%s'")
+         :format(prefix, basename, self:_get_fullname(true), self._parent:_get_commands())
+      table.insert(buf, line)
+   end
+
+   for _, option in ipairs(self._options) do
+      local parts = {prefix}
+
+      if self._parent then
+         table.insert(parts, "-n '__fish_" .. basename .. "_seen_command " .. self:_get_fullname(true) .. "'")
+      end
+
+      for _, alias in ipairs(option._aliases) do
+         if alias:match("^%-.$") then
+            table.insert(parts, "-s " .. alias:sub(2))
+         elseif alias:match("^%-%-.+") then
+            table.insert(parts, "-l " .. alias:sub(3))
+         end
+      end
+
+      if option._choices then
+         table.insert(parts, "-xa '" .. table.concat(option._choices, " ") .. "'")
+      elseif option._minargs > 0 then
+         table.insert(parts, "-r")
+      end
+
+      if option._description then
+         table.insert(parts, "-d '" .. fish_escape(get_short_description(option)) .. "'")
+      end
+
+      table.insert(buf, table.concat(parts, " "))
+   end
+
+   for _, command in ipairs(self._commands) do
+      command:_fish_complete_help(buf, basename)
+   end
+end
+
+function Parser:get_fish_complete()
+   self._basename = base_name(self._name)
+   assert(self:_is_shell_safe())
+   local buf = {}
+
+   if #self._commands > 0 then
+      table.insert(buf, ([[
+function __fish_%s_print_command
+    set -l cmdline (commandline -poc)
+    set -l cmd]]):format(self._basename))
+      self:_fish_get_cmd(buf, 4)
+      table.insert(buf, ([[
+    echo "$cmd"
+end
+
+function __fish_%s_using_command
+    test (__fish_%s_print_command) = "$argv"
+    and return 0
+    or return 1
+end
+
+function __fish_%s_seen_command
+    string match -q "$argv*" (__fish_%s_print_command)
+    and return 0
+    or return 1
+end]]):format(self._basename, self._basename, self._basename, self._basename))
+   end
+
+   self:_fish_complete_help(buf, self._basename)
+   return table.concat(buf, "\n") .. "\n"
+end
+
+local function get_tip(context, wrong_name)
+   local context_pool = {}
+   local possible_name
+   local possible_names = {}
+
+   for name in pairs(context) do
+      if type(name) == "string" then
+         for i = 1, #name do
+            possible_name = name:sub(1, i - 1) .. name:sub(i + 1)
+
+            if not context_pool[possible_name] then
+               context_pool[possible_name] = {}
+            end
+
+            table.insert(context_pool[possible_name], name)
+         end
+      end
+   end
+
+   for i = 1, #wrong_name + 1 do
+      possible_name = wrong_name:sub(1, i - 1) .. wrong_name:sub(i + 1)
+
+      if context[possible_name] then
+         possible_names[possible_name] = true
+      elseif context_pool[possible_name] then
+         for _, name in ipairs(context_pool[possible_name]) do
+            possible_names[name] = true
+         end
+      end
+   end
+
+   local first = next(possible_names)
+
+   if first then
+      if next(possible_names, first) then
+         local possible_names_arr = {}
+
+         for name in pairs(possible_names) do
+            table.insert(possible_names_arr, "'" .. name .. "'")
+         end
+
+         table.sort(possible_names_arr)
+         return "\nDid you mean one of these: " .. table.concat(possible_names_arr, " ") .. "?"
+      else
+         return "\nDid you mean '" .. first .. "'?"
+      end
+   else
+      return ""
+   end
+end
+
+local ElementState = class({
+   invocations = 0
+})
+
+function ElementState:__call(state, element)
+   self.state = state
+   self.result = state.result
+   self.element = element
+   self.target = element._target or element:_get_default_target()
+   self.action, self.result[self.target] = element:_get_action()
+   return self
+end
+
+function ElementState:error(fmt, ...)
+   self.state:error(fmt, ...)
+end
+
+function ElementState:convert(argument, index)
+   local converter = self.element._convert
+
+   if converter then
+      local ok, err
+
+      if type(converter) == "function" then
+         ok, err = converter(argument)
+      elseif type(converter[index]) == "function" then
+         ok, err = converter[index](argument)
+      else
+         ok = converter[argument]
+      end
+
+      if ok == nil then
+         self:error(err and "%s" or "malformed argument '%s'", err or argument)
+      end
+
+      argument = ok
+   end
+
+   return argument
+end
+
+function ElementState:default(mode)
+   return self.element._defmode:find(mode) and self.element._default
+end
+
+local function bound(noun, min, max, is_max)
+   local res = ""
+
+   if min ~= max then
+      res = "at " .. (is_max and "most" or "least") .. " "
+   end
+
+   local number = is_max and max or min
+   return res .. tostring(number) .. " " .. noun ..  (number == 1 and "" or "s")
+end
+
+function ElementState:set_name(alias)
+   self.name = ("%s '%s'"):format(alias and "option" or "argument", alias or self.element._name)
+end
+
+function ElementState:invoke()
+   self.open = true
+   self.overwrite = false
+
+   if self.invocations >= self.element._maxcount then
+      if self.element._overwrite then
+         self.overwrite = true
+      else
+         local num_times_repr = bound("time", self.element._mincount, self.element._maxcount, true)
+         self:error("%s must be used %s", self.name, num_times_repr)
+      end
+   else
+      self.invocations = self.invocations + 1
+   end
+
+   self.args = {}
+
+   if self.element._maxargs <= 0 then
+      self:close()
+   end
+
+   return self.open
+end
+
+function ElementState:check_choices(argument)
+   if self.element._choices then
+      for _, choice in ipairs(self.element._choices) do
+         if argument == choice then
+            return
+         end
+      end
+      local choices_list = "'" .. table.concat(self.element._choices, "', '") .. "'"
+      local is_option = getmetatable(self.element) == Option
+      self:error("%s%s must be one of %s", is_option and "argument for " or "", self.name, choices_list)
+   end
+end
+
+function ElementState:pass(argument)
+   self:check_choices(argument)
+   argument = self:convert(argument, #self.args + 1)
+   table.insert(self.args, argument)
+
+   if #self.args >= self.element._maxargs then
+      self:close()
+   end
+
+   return self.open
+end
+
+function ElementState:complete_invocation()
+   while #self.args < self.element._minargs do
+      self:pass(self.element._default)
+   end
+end
+
+function ElementState:close()
+   if self.open then
+      self.open = false
+
+      if #self.args < self.element._minargs then
+         if self:default("a") then
+            self:complete_invocation()
+         else
+            if #self.args == 0 then
+               if getmetatable(self.element) == Argument then
+                  self:error("missing %s", self.name)
+               elseif self.element._maxargs == 1 then
+                  self:error("%s requires an argument", self.name)
+               end
+            end
+
+            self:error("%s requires %s", self.name, bound("argument", self.element._minargs, self.element._maxargs))
+         end
+      end
+
+      local args
+
+      if self.element._maxargs == 0 then
+         args = self.args[1]
+      elseif self.element._maxargs == 1 then
+         if self.element._minargs == 0 and self.element._mincount ~= self.element._maxcount then
+            args = self.args
+         else
+            args = self.args[1]
+         end
+      else
+         args = self.args
+      end
+
+      self.action(self.result, self.target, args, self.overwrite)
+   end
+end
+
+local ParseState = class({
+   result = {},
+   options = {},
+   arguments = {},
+   argument_i = 1,
+   element_to_mutexes = {},
+   mutex_to_element_state = {},
+   command_actions = {}
+})
+
+function ParseState:__call(parser, error_handler)
+   self.parser = parser
+   self.error_handler = error_handler
+   self.charset = parser:_update_charset()
+   self:switch(parser)
+   return self
+end
+
+function ParseState:error(fmt, ...)
+   self.error_handler(self.parser, fmt:format(...))
+end
+
+function ParseState:switch(parser)
+   self.parser = parser
+
+   if parser._action then
+      table.insert(self.command_actions, {action = parser._action, name = parser._name})
+   end
+
+   for _, option in ipairs(parser._options) do
+      option = ElementState(self, option)
+      table.insert(self.options, option)
+
+      for _, alias in ipairs(option.element._aliases) do
+         self.options[alias] = option
+      end
+   end
+
+   for _, mutex in ipairs(parser._mutexes) do
+      for _, element in ipairs(mutex) do
+         if not self.element_to_mutexes[element] then
+            self.element_to_mutexes[element] = {}
+         end
+
+         table.insert(self.element_to_mutexes[element], mutex)
+      end
+   end
+
+   for _, argument in ipairs(parser._arguments) do
+      argument = ElementState(self, argument)
+      table.insert(self.arguments, argument)
+      argument:set_name()
+      argument:invoke()
+   end
+
+   self.handle_options = parser._handle_options
+   self.argument = self.arguments[self.argument_i]
+   self.commands = parser._commands
+
+   for _, command in ipairs(self.commands) do
+      for _, alias in ipairs(command._aliases) do
+         self.commands[alias] = command
+      end
+   end
+end
+
+function ParseState:get_option(name)
+   local option = self.options[name]
+
+   if not option then
+      self:error("unknown option '%s'%s", name, get_tip(self.options, name))
+   else
+      return option
+   end
+end
+
+function ParseState:get_command(name)
+   local command = self.commands[name]
+
+   if not command then
+      if #self.commands > 0 then
+         self:error("unknown command '%s'%s", name, get_tip(self.commands, name))
+      else
+         self:error("too many arguments")
+      end
+   else
+      return command
+   end
+end
+
+function ParseState:check_mutexes(element_state)
+   if self.element_to_mutexes[element_state.element] then
+      for _, mutex in ipairs(self.element_to_mutexes[element_state.element]) do
+         local used_element_state = self.mutex_to_element_state[mutex]
+
+         if used_element_state and used_element_state ~= element_state then
+            self:error("%s can not be used together with %s", element_state.name, used_element_state.name)
+         else
+            self.mutex_to_element_state[mutex] = element_state
+         end
+      end
+   end
+end
+
+function ParseState:invoke(option, name)
+   self:close()
+   option:set_name(name)
+   self:check_mutexes(option, name)
+
+   if option:invoke() then
+      self.option = option
+   end
+end
+
+function ParseState:pass(arg)
+   if self.option then
+      if not self.option:pass(arg) then
+         self.option = nil
+      end
+   elseif self.argument then
+      self:check_mutexes(self.argument)
+
+      if not self.argument:pass(arg) then
+         self.argument_i = self.argument_i + 1
+         self.argument = self.arguments[self.argument_i]
+      end
+   else
+      local command = self:get_command(arg)
+      self.result[command._target or command._name] = true
+
+      if self.parser._command_target then
+         self.result[self.parser._command_target] = command._name
+      end
+
+      self:switch(command)
+   end
+end
+
+function ParseState:close()
+   if self.option then
+      self.option:close()
+      self.option = nil
+   end
+end
+
+function ParseState:finalize()
+   self:close()
+
+   for i = self.argument_i, #self.arguments do
+      local argument = self.arguments[i]
+      if #argument.args == 0 and argument:default("u") then
+         argument:complete_invocation()
+      else
+         argument:close()
+      end
+   end
+
+   if self.parser._require_command and #self.commands > 0 then
+      self:error("a command is required")
+   end
+
+   for _, option in ipairs(self.options) do
+      option.name = option.name or ("option '%s'"):format(option.element._name)
+
+      if option.invocations == 0 then
+         if option:default("u") then
+            option:invoke()
+            option:complete_invocation()
+            option:close()
+         end
+      end
+
+      local mincount = option.element._mincount
+
+      if option.invocations < mincount then
+         if option:default("a") then
+            while option.invocations < mincount do
+               option:invoke()
+               option:close()
+            end
+         elseif option.invocations == 0 then
+            self:error("missing %s", option.name)
+         else
+            self:error("%s must be used %s", option.name, bound("time", mincount, option.element._maxcount))
+         end
+      end
+   end
+
+   for i = #self.command_actions, 1, -1 do
+      self.command_actions[i].action(self.result, self.command_actions[i].name)
+   end
+end
+
+function ParseState:parse(args)
+   for _, arg in ipairs(args) do
+      local plain = true
+
+      if self.handle_options then
+         local first = arg:sub(1, 1)
+
+         if self.charset[first] then
+            if #arg > 1 then
+               plain = false
+
+               if arg:sub(2, 2) == first then
+                  if #arg == 2 then
+                     if self.options[arg] then
+                        local option = self:get_option(arg)
+                        self:invoke(option, arg)
+                     else
+                        self:close()
+                     end
+
+                     self.handle_options = false
+                  else
+                     local equals = arg:find "="
+                     if equals then
+                        local name = arg:sub(1, equals - 1)
+                        local option = self:get_option(name)
+
+                        if option.element._maxargs <= 0 then
+                           self:error("option '%s' does not take arguments", name)
+                        end
+
+                        self:invoke(option, name)
+                        self:pass(arg:sub(equals + 1))
+                     else
+                        local option = self:get_option(arg)
+                        self:invoke(option, arg)
+                     end
+                  end
+               else
+                  for i = 2, #arg do
+                     local name = first .. arg:sub(i, i)
+                     local option = self:get_option(name)
+                     self:invoke(option, name)
+
+                     if i ~= #arg and option.element._maxargs > 0 then
+                        self:pass(arg:sub(i + 1))
+                        break
+                     end
+                  end
+               end
+            end
+         end
+      end
+
+      if plain then
+         self:pass(arg)
+      end
+   end
+
+   self:finalize()
+   return self.result
+end
+
+function Parser:error(msg)
+   io.stderr:write(("%s\n\nError: %s\n"):format(self:get_usage(), msg))
+   os.exit(1)
+end
+
+-- Compatibility with strict.lua and other checkers:
+local default_cmdline = rawget(_G, "arg") or {}
+
+function Parser:_parse(args, error_handler)
+   return ParseState(self, error_handler):parse(args or default_cmdline)
+end
+
+function Parser:parse(args)
+   return self:_parse(args, self.error)
+end
+
+local function xpcall_error_handler(err)
+   return tostring(err) .. "\noriginal " .. debug.traceback("", 2):sub(2)
+end
+
+function Parser:pparse(args)
+   local parse_error
+
+   local ok, result = xpcall(function()
+      return self:_parse(args, function(_, err)
+         parse_error = err
+         error(err, 0)
+      end)
+   end, xpcall_error_handler)
+
+   if ok then
+      return true, result
+   elseif not parse_error then
+      error(result, 0)
+   else
+      return false, parse_error
+   end
+end
+
+local argparse = {}
+
+argparse.version = "0.7.0"
+
+setmetatable(argparse, {__call = function(_, ...)
+   return Parser(default_cmdline[0]):add_help(true)(...)
+end})
+
+return argparse
diff --git a/src/luarocks/cmd.lua b/src/luarocks/cmd.lua
index 1ead6c4b..f424f488 100644
--- a/src/luarocks/cmd.lua
+++ b/src/luarocks/cmd.lua
@@ -2,16 +2,14 @@
 --- Functions for command-line scripts.
 local cmd = {}
 
-local unpack = unpack or table.unpack
-
 local loader = require("luarocks.loader")
 local util = require("luarocks.util")
 local path = require("luarocks.path")
-local deps = require("luarocks.deps")
 local cfg = require("luarocks.core.cfg")
 local dir = require("luarocks.dir")
 local fun = require("luarocks.fun")
 local fs = require("luarocks.fs")
+local argparse = require("luarocks.argparse")
 
 local hc_ok, hardcoded = pcall(require, "luarocks.core.hardcoded")
 if not hc_ok then
@@ -41,11 +39,11 @@ local function check_popen()
    end
 end
 
-local process_tree_flags
+local process_tree_args
 do
-   local function replace_tree(flags, root, tree)
+   local function replace_tree(args, root, tree)
       root = dir.normalize(root)
-      flags["tree"] = root
+      args.tree = root
       path.use_tree(tree or root)
    end
 
@@ -61,44 +59,44 @@ do
       cfg.deploy_lib_dir = cfg.deploy_lib_dir:gsub("/+$", "")
    end
 
-   process_tree_flags = function(flags, project_dir)
+   process_tree_args = function(args, project_dir)
    
-      if flags["global"] then
+      if args.global then
          cfg.local_by_default = false
       end
 
-      if flags["tree"] then
+      if args.tree then
          local named = false
          for _, tree in ipairs(cfg.rocks_trees) do
-            if type(tree) == "table" and flags["tree"] == tree.name then
+            if type(tree) == "table" and args.tree == tree.name then
                if not tree.root then
                   return nil, "Configuration error: tree '"..tree.name.."' has no 'root' field."
                end
-               replace_tree(flags, tree.root, tree)
+               replace_tree(args, tree.root, tree)
                named = true
                break
             end
          end
          if not named then
-            local root_dir = fs.absolute_name(flags["tree"])
-            replace_tree(flags, root_dir)
+            local root_dir = fs.absolute_name(args.tree)
+            replace_tree(args, root_dir)
          end
-      elseif flags["local"] then
+      elseif args["local"] then
          if not cfg.home_tree then
             return nil, "The --local flag is meant for operating in a user's home directory.\n"..
                "You are running as a superuser, which is intended for system-wide operation.\n"..
                "To force using the superuser's home, use --tree explicitly."
          else
-            replace_tree(flags, cfg.home_tree)
+            replace_tree(args, cfg.home_tree)
          end
-      elseif flags["project-tree"] then
-         local tree = flags["project-tree"]
+      elseif args.project_tree then
+         local tree = args.project_tree
          table.insert(cfg.rocks_trees, 1, { name = "project", root = tree } )
          loader.load_rocks_trees()
          path.use_tree(tree)
       elseif cfg.local_by_default then
          if cfg.home_tree then
-            replace_tree(flags, cfg.home_tree)
+            replace_tree(args, cfg.home_tree)
          end
       elseif project_dir then
          local project_tree = project_dir .. "/lua_modules"
@@ -119,26 +117,26 @@ do
    end
 end
 
-local function process_server_flags(flags)
-   if flags["server"] then
-      local protocol, pathname = dir.split_url(flags["server"])
+local function process_server_args(args)
+   if args.server then
+      local protocol, pathname = dir.split_url(args.server)
       table.insert(cfg.rocks_servers, 1, protocol.."://"..pathname)
    end
 
-   if flags["dev"] then
+   if args.dev then
       local append_dev = function(s) return dir.path(s, "dev") end
       local dev_servers = fun.traverse(cfg.rocks_servers, append_dev)
       cfg.rocks_servers = fun.concat(dev_servers, cfg.rocks_servers)
    end
 
-   if flags["only-server"] then
-      if flags["dev"] then
+   if args.only_server then
+      if args.dev then
          return nil, "--only-server cannot be used with --dev"
       end
-      if flags["server"] then
+      if args.server then
          return nil, "--only-server cannot be used with --server"
       end
-      cfg.rocks_servers = { flags["only-server"] }
+      cfg.rocks_servers = { args.only_server }
    end
 
    return true
@@ -174,7 +172,7 @@ end
 
 local init_config
 do
-   local detect_config_via_flags
+   local detect_config_via_args
    do
       local function find_project_dir(project_tree)
          if project_tree then
@@ -193,7 +191,7 @@ do
          return nil
       end
    
-      local function find_default_lua_version(flags, project_dir)
+      local function find_default_lua_version(args, project_dir)
          if hardcoded.FORCE_CONFIG then
             return nil
          end
@@ -212,7 +210,7 @@ do
             if mod then
                local pok, ver = pcall(mod)
                if pok and type(ver) == "string" and ver:match("%d+.%d+") then
-                  if flags["verbose"] then
+                  if args.verbose then
                      util.printout("Defaulting to Lua " .. ver .. " based on " .. f .. " ...")
                   end
                   return ver
@@ -230,13 +228,13 @@ do
          end)
       end
    
-      local function detect_lua_via_flags(flags, project_dir)
-         local lua_version = flags["lua-version"]
-                             or find_default_lua_version(flags, project_dir)
+      local function detect_lua_via_args(args, project_dir)
+         local lua_version = args.lua_version
+                             or find_default_lua_version(args, project_dir)
                              or (project_dir and find_version_from_config(project_dir))
       
-         if flags["lua-dir"] then
-            local detected, err = util.find_lua(flags["lua-dir"], lua_version)
+         if args.lua_dir then
+            local detected, err = util.find_lua(args.lua_dir, lua_version)
             if not detected then
                die(err)
             end
@@ -264,14 +262,14 @@ do
          return {}
       end
       
-      detect_config_via_flags = function(flags)
-         local project_dir, given = find_project_dir(flags["project-tree"])
-         local detected = detect_lua_via_flags(flags, project_dir)
-         if flags["lua-version"] then
-            detected.given_lua_version = flags["lua-version"]
+      detect_config_via_args = function(args)
+         local project_dir, given = find_project_dir(args.project_tree)
+         local detected = detect_lua_via_args(args, project_dir)
+         if args.lua_version then
+            detected.given_lua_version = args.lua_version
          end
-         if flags["lua-dir"] then
-            detected.given_lua_dir = flags["lua-dir"]
+         if args.lua_dir then
+            detected.given_lua_dir = args.lua_dir
          end
          if given then
             detected.given_project_dir = project_dir
@@ -281,8 +279,8 @@ do
       end
    end
    
-   init_config = function(flags)
-      local detected = detect_config_via_flags(flags)
+   init_config = function(args)
+      local detected = detect_config_via_args(args)
    
       -- FIXME A quick hack for the experimental Windows build
       if os.getenv("LUAROCKS_CROSS_COMPILING") then
@@ -306,6 +304,135 @@ do
    end
 end
 
+local variables_help = [[
+Variables:
+   Variables from the "variables" table of the configuration file can be
+   overridden with VAR=VALUE assignments.
+
+]]
+
+local function get_status(status)
+   return status and "ok" or "not found"
+end
+
+local function get_config_text(cfg)
+   local buf = "Configuration:\n   Lua version: "..cfg.lua_version.."\n"
+   if cfg.luajit_version then
+      buf = buf.."   LuaJIT version: "..cfg.luajit_version.."\n"
+   end
+   buf = buf.."\n   Configuration files:\n"
+   local conf = cfg.config_files
+   buf = buf.."      System  : "..fs.absolute_name(conf.system.file).." ("..get_status(conf.system.found)..")\n"
+   if conf.user.file then
+      buf = buf.."      User    : "..fs.absolute_name(conf.user.file).." ("..get_status(conf.user.found)..")\n"
+   else
+      buf = buf.."      User    : disabled in this LuaRocks installation.\n"
+   end
+   if conf.project then
+      buf = buf.."      Project : "..fs.absolute_name(conf.project.file).." ("..get_status(conf.project.found)..")\n"
+   end
+   buf = buf.."\n   Rocks trees in use: \n"
+   for _, tree in ipairs(cfg.rocks_trees) do
+      if type(tree) == "string" then
+         buf = buf.."      "..fs.absolute_name(tree)
+      else
+         local name = tree.name and " (\""..tree.name.."\")" or ""
+         buf = buf.."      "..fs.absolute_name(tree.root)..name
+      end
+   end
+
+   return buf.."\n"
+end
+
+local function get_parser(description, cmd_modules)
+   local basename = dir.base_name(program)
+   local parser = argparse(
+      basename, "LuaRocks "..cfg.program_version..", the Lua package manager\n\n"..
+      program.." - "..description, variables_help.."Run '"..basename..
+      "' without any arguments to see the configuration.")
+      :help_max_width(80)
+      :add_help_command()
+      :add_complete_command({
+         help_max_width = 100,
+         summary = "Output a shell completion script.",
+         description = [[
+Output a shell completion script.
+
+Enabling completions for Bash:
+
+   Add the following line to your ~/.bashrc:
+      source <(]]..basename..[[ completion bash)
+   or save the completion script to the local completion directory:
+      ]]..basename..[[ completion bash > ~/.local/share/bash-completion/completions/]]..basename..[[
+
+
+Enabling completions for Zsh:
+
+   Save the completion script to a file in your $fpath.
+   You can add a new directory to your $fpath by adding e.g.
+      fpath=(~/.zfunc $fpath)
+   to your ~/.zshrc.
+   Then run:
+      ]]..basename..[[ completion zsh > ~/.zfunc/_]]..basename..[[
+
+
+Enabling completion for Fish:
+
+   Add the following line to your ~/.config/fish/config.fish:
+      ]]..basename..[[ completion fish | source
+   or save the completion script to the local completion directory:
+      ]]..basename..[[ completion fish > ~/.config/fish/completions/]]..basename..[[.fish
+]]})
+      :command_target("command")
+      :require_command(false)
+
+   parser:flag("--version", "Show version info and exit.")
+      :action(function()
+         util.printout(program.." "..cfg.program_version)
+         util.printout(description)
+         util.printout()
+         os.exit(cmd.errorcodes.OK)
+      end)
+   parser:flag("--dev", "Enable the sub-repositories in rocks servers for "..
+      "rockspecs of in-development versions.")
+   parser:option("--server", "Fetch rocks/rockspecs from this server "..
+      "(takes priority over config file).")
+   parser:option("--only-server", "Fetch rocks/rockspecs from this server only "..
+      "(overrides any entries in the config file).")
+      :argname("<server>")
+   parser:option("--only-sources", "Restrict downloads to paths matching the given URL.")
+      :argname("<url>")
+   parser:option("--namespace", "Specify the rocks server namespace to use.")
+   parser:option("--lua-dir", "Which Lua installation to use.")
+      :argname("<prefix>")
+   parser:option("--lua-version", "Which Lua version to use.")
+      :argname("<ver>")
+   parser:option("--tree", "Which tree to operate on.")
+   parser:flag("--local", "Use the tree in the user's home directory.\n"..
+      "To enable it, see '"..program.." help path'.")
+   parser:flag("--global", "Use the system tree when `local_by_default` is `true`.")
+   parser:flag("--verbose", "Display verbose output of commands executed.")
+   parser:option("--timeout", "Timeout on network operations, in seconds.\n"..
+      "0 means no timeout (wait forever). Default is "..
+      tostring(cfg.connection_timeout)..".")
+      :argname("<seconds>")
+      :convert(tonumber)
+
+   -- Used internally to force the use of a particular project tree
+   parser:option("--project-tree"):hidden(true)
+   -- Compatibility for old names of some options
+   parser:option("--to"):target("tree"):hidden(true)
+   parser:option("--from"):target("server"):hidden(true)
+   parser:option("--only-from"):target("only_server"):hidden(true)
+   parser:option("--only-sources-from"):target("only_sources"):hidden(true)
+
+   for _, module in util.sortedpairs(cmd_modules) do
+      module.add_to_parser(parser)
+   end
+
+   return parser
+end
+
 --- Main command-line processor.
 -- Parses input arguments and calls the appropriate driver function
 -- to execute the action requested on the command-line, forwarding
@@ -318,7 +445,20 @@ function cmd.run_command(description, commands, external_namespace, ...)
 
    check_popen()
 
-   local function process_arguments(...)
+   fs.init()
+
+   for _, module_name in ipairs(fs.modules(external_namespace)) do
+      if not commands[module_name] then
+         commands[module_name] = external_namespace.."."..module_name
+      end
+   end
+
+   local cmd_modules = {}
+   for name, module in pairs(commands) do
+      cmd_modules[name] = require(module)
+   end
+
+   local function process_cmdline_vars(...)
       local args = {...}
       local cmdline_vars = {}
       local last = #args
@@ -340,69 +480,38 @@ function cmd.run_command(description, commands, external_namespace, ...)
             end
          end
       end
-      local nonflags = { util.parse_flags(unpack(args)) }
-      local flags = table.remove(nonflags, 1)
-      if flags.ERROR then
-         die(flags.ERROR.." See --help.")
-      end
 
-      -- Compatibility for old names of some flags
-      if flags["to"] then flags["tree"] = flags["to"] end
-      if flags["from"] then flags["server"] = flags["from"] end
-      if flags["nodeps"] then flags["deps-mode"] = "none" end
-      if flags["only-from"] then flags["only-server"] = flags["only-from"] end
-      if flags["only-sources-from"] then flags["only-sources"] = flags["only-sources-from"] end
-
-      return flags, nonflags, cmdline_vars
+      return args, cmdline_vars
    end
 
-   local flags, nonflags, cmdline_vars = process_arguments(...)
+   local args, cmdline_vars = process_cmdline_vars(...)
+   local parser = get_parser(description, cmd_modules)
+   args = parser:parse(args)
 
-   if flags["timeout"] then   -- setting it in the config file will kick-in earlier in the process
-      local timeout = tonumber(flags["timeout"])
-      if timeout then
-         cfg.connection_timeout = timeout
-      else
-         die "Argument error: --timeout expects a numeric argument."
-      end
+   -- Compatibility for old flag
+   if args.nodeps then
+      args.deps_mode = "none"
    end
 
-   local command
-   if flags["help"] or #nonflags == 0 then
-      command = "help"
-   else
-      command = table.remove(nonflags, 1)
+   if args.timeout then -- setting it in the config file will kick-in earlier in the process
+      cfg.connection_timeout = args.timeout
    end
-   command = command:gsub("-", "_")
 
-   if command == "config" then
-      if nonflags[1] == "lua_version" and nonflags[2] then
-         flags["lua-version"] = nonflags[2]
-      elseif nonflags[1] == "lua_dir" and nonflags[2] then
-         flags["lua-dir"] = nonflags[2]
+   if args.command == "config" then
+      if args.key == "lua_version" and args.value then
+         args.lua_version = args.value
+      elseif args.key == "lua_dir" and args.value then
+         args.lua_dir = args.value
       end
    end
 
-   if flags["deps-mode"] and not deps.check_deps_mode_flag(flags["deps-mode"]) then
-      die("Invalid entry for --deps-mode.")
-   end
-   
    -----------------------------------------------------------------------------
-   local lua_found, err = init_config(flags)
+   local lua_found, err = init_config(args)
    if err then
       die(err)
    end
    -----------------------------------------------------------------------------
 
-   if flags["version"] then
-      util.printout(program.." "..cfg.program_version)
-      util.printout(description)
-      util.printout()
-      os.exit(cmd.errorcodes.OK)
-   end
-
-   fs.init()
-
    -- if the Lua interpreter wasn't explicitly found before cfg.init,
    -- try again now.
    if not lua_found then
@@ -414,7 +523,7 @@ function cmd.run_command(description, commands, external_namespace, ...)
    if not lua_found then
       util.warning("Could not find a Lua " .. cfg.lua_version .. " interpreter in your PATH. " ..
                    "Modules may not install with the correct configurations. " ..
-                   "You may want to specify to the path prefix to your build " ..
+                   "You may want to specify the path prefix to your build " ..
                    "of Lua " .. cfg.lua_version .. " using --lua-dir")
    end
    cfg.lua_found = lua_found
@@ -423,13 +532,7 @@ function cmd.run_command(description, commands, external_namespace, ...)
       cfg.project_dir = fs.absolute_name(cfg.project_dir)
    end
 
-   for _, module_name in ipairs(fs.modules(external_namespace)) do
-      if not commands[module_name] then
-         commands[module_name] = external_namespace.."."..module_name
-      end
-   end
-
-   if flags["verbose"] then
+   if args.verbose then
       cfg.verbose = true
       fs.verbose()
    end
@@ -438,24 +541,22 @@ function cmd.run_command(description, commands, external_namespace, ...)
       die("Current directory does not exist. Please run LuaRocks from an existing directory.")
    end
 
-   ok, err = process_tree_flags(flags, cfg.project_dir)
+   local ok, err = process_tree_args(args, cfg.project_dir)
    if not ok then
       die(err)
    end
 
-   ok, err = process_server_flags(flags)
+   ok, err = process_server_args(args)
    if not ok then
       die(err)
    end
 
-   if flags["only-sources"] then
-      cfg.only_sources_from = flags["only-sources"]
+   if args.only_sources then
+      cfg.only_sources_from = args.only_sources
    end
 
-   if command ~= "help" then
-      for k, v in pairs(cmdline_vars) do
-         cfg.variables[k] = v
-      end
+   for k, v in pairs(cmdline_vars) do
+      cfg.variables[k] = v
    end
 
    -- if running as superuser, use system cache dir
@@ -463,22 +564,23 @@ function cmd.run_command(description, commands, external_namespace, ...)
       cfg.local_cache = dir.path(fs.system_cache_dir(), "luarocks")
    end
 
-   if commands[command] then
-      local cmd_mod = require(commands[command])
-      local call_ok, ok, err, exitcode = xpcall(function()
-         if command == "help" then
-            return cmd_mod.command(description, commands, unpack(nonflags))
-         else
-            return cmd_mod.command(flags, unpack(nonflags))
-         end
-      end, error_handler)
-      if not call_ok then
-         die(ok, cmd.errorcodes.CRASH)
-      elseif not ok then
-         die(err, exitcode)
-      end
-   else
-      die("Unknown command: "..command)
+   if not args.command then
+      parser:epilog(variables_help..get_config_text(cfg))
+      util.printout()
+      util.printout(parser:get_help())
+      util.printout()
+      os.exit(cmd.errorcodes.OK)
+   end
+
+   local cmd_mod = cmd_modules[args.command]
+   local call_ok, ok, err, exitcode = xpcall(function()
+      return cmd_mod.command(args)
+   end, error_handler)
+
+   if not call_ok then
+      die(ok, cmd.errorcodes.CRASH)
+   elseif not ok then
+      die(err, exitcode)
    end
    util.run_scheduled_functions()
 end
diff --git a/src/luarocks/cmd/build.lua b/src/luarocks/cmd/build.lua
index 23a94fa7..0654b4eb 100644
--- a/src/luarocks/cmd/build.lua
+++ b/src/luarocks/cmd/build.lua
@@ -18,40 +18,20 @@ local search = require("luarocks.search")
 local make = require("luarocks.cmd.make")
 local cmd = require("luarocks.cmd")
 
-cmd_build.help_summary = "build/compile a rock."
-cmd_build.help_arguments = "[<flags...>] {<rockspec>|<rock>|<name> [<version>]}"
-cmd_build.help = [[
-Build and install a rock, compiling its C parts if any.
-Argument may be a rockspec file, a source rock file
-or the name of a rock to be fetched from a repository.
-
---pack-binary-rock  Do not install rock. Instead, produce a .rock file
-                    with the contents of compilation in the current
-                    directory.
-
---keep              Do not remove previously installed versions of the
-                    rock after building a new one. This behavior can
-                    be made permanent by setting keep_other_versions=true
-                    in the configuration file.
-
---branch=<name>     Override the `source.branch` field in the loaded
-                    rockspec. Allows to specify a different branch to 
-                    fetch. Particularly for "dev" rocks.
-
---only-deps         Installs only the dependencies of the rock.
-
---verify            Verify signature of the rockspec or src.rock being
-                    built. If the rockspec or src.rock is being downloaded,
-                    LuaRocks will attempt to download the signature as well.
-                    Otherwise, the signature file should be already
-                    available locally in the same directory.
-                    You need the signer’s public key in your local
-                    keyring for this option to work properly.
-
---sign              To be used with --pack-binary-rock. Also produce
-                    a signature file for the generated .rock file.
-
-]]..util.deps_mode_help()
+function cmd_build.add_to_parser(parser)
+   local cmd = parser:command("build", "Build and install a rock, compiling its C parts if any.\n"..
+      "If no arguments are given, behaves as luarocks make.", util.see_also())
+      :summary("Build/compile a rock.")
+
+   cmd:argument("rock", "A rockspec file, a source rock file, or the name of "..
+      "a rock to be fetched from a repository.")
+      :args("?")
+   cmd:argument("version", "Rock version.")
+      :args("?")
+
+   cmd:flag("--only-deps", "Installs only the dependencies of the rock.")
+   make.cmd_options(cmd)
+end
 
 --- Build and install a rock.
 -- @param rock_filename string: local or remote filename of a rock.
@@ -132,58 +112,54 @@ local function remove_doc_dir(name, version)
 end
 
 --- Driver function for "build" command.
--- @param name string: A local or remote rockspec or rock file.
 -- If a package name is given, forwards the request to "search" and,
 -- if returned a result, installs the matching rock.
--- @param version string: When passing a package name, a version number may
--- also be given.
+-- When passing a package name, a version number may also be given.
 -- @return boolean or (nil, string, exitcode): True if build was successful; nil and an
 -- error message otherwise. exitcode is optionally returned.
-function cmd_build.command(flags, name, version)
-   assert(type(name) == "string" or not name)
-   assert(type(version) == "string" or not version)
-   
-   if not name then
-      return make.command(flags)
+function cmd_build.command(args)
+   if not args.rock then
+      return make.command(args)
    end
 
-   name = util.adjust_name_and_namespace(name, flags)
+   local name = util.adjust_name_and_namespace(args.rock, args)
 
    local opts = build.opts({
       need_to_fetch = true,
       minimal_mode = false,
-      deps_mode = deps.get_deps_mode(flags),
-      build_only_deps = not not flags["only-deps"],
-      namespace = flags["namespace"],
-      branch = not not flags["branch"],
-      verify = not not flags["verify"],
+      deps_mode = deps.get_deps_mode(args),
+      build_only_deps = not not args.only_deps,
+      namespace = args.namespace,
+      branch = not not args.branch,
+      verify = not not args.verify,
    })
 
-   if flags["sign"] and not flags["pack-binary-rock"] then
+   if args.sign and not args.pack_binary_rock then
       return nil, "In the build command, --sign is meant to be used only with --pack-binary-rock"
    end
 
-   if flags["pack-binary-rock"] then
-      return pack.pack_binary_rock(name, version, flags["sign"], function()
+   if args.pack_binary_rock then
+      return pack.pack_binary_rock(name, args.version, args.sign, function()
          opts.build_only_deps = false
-         local status, err, errcode = do_build(name, version, opts)
-         if status and flags["no-doc"] then
-            remove_doc_dir(name, version)
+         local status, err, errcode = do_build(name, args.version, opts)
+         if status and args.no_doc then
+            remove_doc_dir(name, args.version)
          end
          return status, err, errcode
       end)
    end
    
-   local ok, err = fs.check_command_permissions(flags)
+   local ok, err = fs.check_command_permissions(args)
    if not ok then
       return nil, err, cmd.errorcodes.PERMISSIONDENIED
    end
 
-   ok, err = do_build(name, version, opts)
+   ok, err = do_build(name, args.version, opts)
    if not ok then return nil, err end
+   local version
    name, version = ok, err
 
-   if flags["no-doc"] then
+   if args.no_doc then
       remove_doc_dir(name, version)
    end
 
@@ -191,15 +167,15 @@ function cmd_build.command(flags, name, version)
       util.printout("Stopping after installing dependencies for " ..name.." "..version)
       util.printout()
    else
-      if (not flags["keep"]) and not cfg.keep_other_versions then
-         local ok, err = remove.remove_other_versions(name, version, flags["force"], flags["force-fast"])
+      if (not args.keep) and not cfg.keep_other_versions then
+         local ok, err = remove.remove_other_versions(name, version, args.force, args.force_fast)
          if not ok then
             util.printerr(err)
          end
       end
    end
 
-   writer.check_dependencies(nil, deps.get_deps_mode(flags))
+   writer.check_dependencies(nil, deps.get_deps_mode(args))
    return name, version
 end
 
diff --git a/src/luarocks/cmd/config.lua b/src/luarocks/cmd/config.lua
index b3cb5e07..59dafdb5 100644
--- a/src/luarocks/cmd/config.lua
+++ b/src/luarocks/cmd/config.lua
@@ -9,21 +9,22 @@ local deps = require("luarocks.deps")
 local dir = require("luarocks.dir")
 local fs = require("luarocks.fs")
 
-config_cmd.help_summary = "Query information about the LuaRocks configuration."
-config_cmd.help_arguments = "(<key> | <key> <value> --scope=<scope> | <key> --unset --scope=<scope> | )"
-config_cmd.help = [[
-* When given a configuration key, it prints the value of that key
-  according to the currently active configuration (taking into account
-  all config files and any command-line flags passed)
+function config_cmd.add_to_parser(parser)
+   local cmd = parser:command("config", [[
+Query information about the LuaRocks configuration.
+
+* When given a configuration key, it prints the value of that key according to
+  the currently active configuration (taking into account all config files and
+  any command-line flags passed)
 
   Examples:
      luarocks config lua_interpreter
      luarocks config variables.LUA_INCDIR
      luarocks config lua_version
 
-* When given a configuration key and a value,
-  it overwrites the config file (see the --scope option below to determine which)
-  and replaces the value of the given key with the given value.
+* When given a configuration key and a value, it overwrites the config file (see
+  the --scope option below to determine which) and replaces the value of the
+  given key with the given value.
 
   * `lua_dir` is a special key as it checks for a valid Lua installation
     (equivalent to --lua-dir) and sets several keys at once.
@@ -35,33 +36,42 @@ config_cmd.help = [[
      luarocks config lua_dir /usr/local
      luarocks config lua_version 5.3
 
-* When given a configuration key and --unset,
-  it overwrites the config file (see the --scope option below to determine which)
-  and deletes that key from the file.
+* When given a configuration key and --unset, it overwrites the config file (see
+  the --scope option below to determine which) and deletes that key from the
+  file.
 
   Example: luarocks config variables.OPENSSL_DIR --unset
 
-* When given no arguments, it prints the entire currently active
-  configuration, resulting from reading the config files from
-  all scopes.
-
-  Example: luarocks config
-
-OPTIONS
---scope=<scope>   The scope indicates which config file should be rewritten.
-                  Accepted values are "system", "user" or "project".
-                  * Using a wrapper created with `luarocks init`,
-                    the default is "project".
-                  * Using --local (or when `local_by_default` is `true`),
-                    the default is "user".
-                  * Otherwise, the default is "system".
-
---json           Output as JSON
-]]
-config_cmd.help_see_also = [[
-        https://github.com/luarocks/luarocks/wiki/Config-file-format
-        for detailed information on the LuaRocks config file format.
-]]
+* When given no arguments, it prints the entire currently active configuration,
+  resulting from reading the config files from all scopes.
+
+  Example: luarocks config]], util.see_also([[
+   https://github.com/luarocks/luarocks/wiki/Config-file-format
+   for detailed information on the LuaRocks config file format.
+]]))
+      :summary("Query information about the LuaRocks configuration.")
+
+   cmd:argument("key", "The configuration key.")
+      :args("?")
+   cmd:argument("value", "The configuration value.")
+      :args("?")
+
+   cmd:option("--scope", "The scope indicates which config file should be rewritten.\n"..
+      '* Using a wrapper created with `luarocks init`, the default is "project".\n'..
+      '* Using --local (or when `local_by_default` is `true`), the default is "user".\n'..
+      '* Otherwise, the default is "system".')
+      :choices({"system", "user", "project"})
+   cmd:flag("--unset", "Delete the key from the configuration file.")
+   cmd:flag("--json", "Output as JSON.")
+
+   -- Deprecated flags
+   cmd:flag("--lua-incdir"):hidden(true)
+   cmd:flag("--lua-libdir"):hidden(true)
+   cmd:flag("--lua-ver"):hidden(true)
+   cmd:flag("--system-config"):hidden(true)
+   cmd:flag("--user-config"):hidden(true)
+   cmd:flag("--rock-trees"):hidden(true)
+end
 
 local function config_file(conf)
    print(dir.normalize(conf.file))
@@ -218,45 +228,40 @@ local function write_entries(keys, scope, do_unset)
    end
 end
 
-local function check_scope(flags)
-   local scope = flags["scope"]
-                 or (flags["local"] and "user")
-                 or (flags["project-tree"] and "project")
-                 or (cfg.local_by_default and "user")
-                 or "system"
-   if scope ~= "system" and scope ~= "user" and scope ~= "project" then
-      return nil, "Valid values for scope are: system, user, project"
-   end
-
-   return scope
+local function get_scope(args)
+   return args.scope
+          or (args["local"] and "user")
+          or (args.project_tree and "project")
+          or (cfg.local_by_default and "user")
+          or "system"
 end
 
 --- Driver function for "config" command.
 -- @return boolean: True if succeeded, nil on errors.
-function config_cmd.command(flags, var, val)
+function config_cmd.command(args)
    deps.check_lua_incdir(cfg.variables)
    deps.check_lua_libdir(cfg.variables)
    
    -- deprecated flags
-   if flags["lua-incdir"] then
+   if args.lua_incdir then
       print(cfg.variables.LUA_INCDIR)
       return true
    end
-   if flags["lua-libdir"] then
+   if args.lua_libdir then
       print(cfg.variables.LUA_LIBDIR)
       return true
    end
-   if flags["lua-ver"] then
+   if args.lua_ver then
       print(cfg.lua_version)
       return true
    end
-   if flags["system-config"] then
+   if args.system_config then
       return config_file(cfg.config_files.system)
    end
-   if flags["user-config"] then
+   if args.user_config then
       return config_file(cfg.config_files.user)
    end
-   if flags["rock-trees"] then
+   if args.rock_trees then
       for _, tree in ipairs(cfg.rocks_trees) do
         if type(tree) == "string" then
            util.printout(dir.normalize(tree))
@@ -268,29 +273,22 @@ function config_cmd.command(flags, var, val)
       return true
    end
 
-   if var == "lua_version" and val then
-      local scope, err = check_scope(flags)
-      if not scope then
-         return nil, err
-      end
-
+   if args.key == "lua_version" and args.value then
+      local scope = get_scope(args)
       if scope == "project" and not cfg.config_files.project then
          return nil, "Current directory is not part of a project. You may want to run `luarocks init`."
       end
 
       local prefix = dir.dir_name(cfg.config_files[scope].file)
-      local ok, err = persist.save_default_lua_version(prefix, val)
+      local ok, err = persist.save_default_lua_version(prefix, args.value)
       if not ok then
          return nil, "could not set default Lua version: " .. err
       end
-      print("Lua version will default to " .. val .. " in " .. prefix)
+      print("Lua version will default to " .. args.value .. " in " .. prefix)
    end
    
-   if var == "lua_dir" and val then
-      local scope, err = check_scope(flags)
-      if not scope then
-         return nil, err
-      end
+   if args.key == "lua_dir" and args.value then
+      local scope = get_scope(args)
       local keys = {
          ["variables.LUA_DIR"] = cfg.variables.LUA_DIR,
          ["variables.LUA_BINDIR"] = cfg.variables.LUA_BINDIR,
@@ -298,25 +296,21 @@ function config_cmd.command(flags, var, val)
          ["variables.LUA_LIBDIR"] = cfg.variables.LUA_LIBDIR,
          ["lua_interpreter"] = cfg.lua_interpreter,
       }
-      return write_entries(keys, scope, flags["unset"])
+      return write_entries(keys, scope, args.unset)
    end
 
-   if var then
-      if val or flags["unset"] then
-         local scope, err = check_scope(flags)
-         if not scope then
-            return nil, err
-         end
-   
-         return write_entries({ [var] = val }, scope, flags["unset"])
+   if args.key then
+      if args.value or args.unset then
+         local scope = get_scope(args)
+         return write_entries({ [args.key] = args.value }, scope, args.unset)
       else
-         return print_entry(var, cfg, flags["json"])
+         return print_entry(args.key, cfg, args.json)
       end
    end
 
    local cleancfg = cleanup(cfg)
 
-   if flags["json"] then
+   if args.json then
       return print_json(cleancfg)
    else
       print(persist.save_from_table_to_string(cleancfg))
diff --git a/src/luarocks/cmd/doc.lua b/src/luarocks/cmd/doc.lua
index a2472be4..4b3335d8 100644
--- a/src/luarocks/cmd/doc.lua
+++ b/src/luarocks/cmd/doc.lua
@@ -12,19 +12,22 @@ local fetch = require("luarocks.fetch")
 local fs = require("luarocks.fs")
 local download = require("luarocks.download")
 
-doc.help_summary = "Show documentation for an installed rock."
-
-doc.help = [[
-<argument> is an existing package name.
-Without any flags, tries to load the documentation
-using a series of heuristics.
-With these flags, return only the desired information:
-
---home      Open the home page of project.
---list      List documentation files only.
-
-For more information about a rock, see the 'show' command.
-]]
+function doc.add_to_parser(parser)
+   local cmd = parser:command("doc", "Show documentation for an installed rock.\n\n"..
+      "Without any flags, tries to load the documentation using a series of heuristics.\n"..
+      "With flags, return only the desired information.", util.see_also([[
+   For more information about a rock, see the 'show' command.
+]]))
+      :summary("Show documentation for an installed rock.")
+
+   cmd:argument("rock", "Name of the rock.")
+   cmd:argument("version", "Version of the rock.")
+      :args("?")
+
+   cmd:flag("--home", "Open the home page of project.")
+   cmd:flag("--list", "List documentation files only.")
+   cmd:flag("--porcelain", "Produce machine-friendly output.")
+end
 
 local function show_homepage(homepage, name, version)
    if not homepage then
@@ -54,17 +57,12 @@ local function try_to_open_homepage(name, version)
 end
 
 --- Driver function for "doc" command.
--- @param name or nil: an existing package name.
--- @param version string or nil: a version may also be passed.
 -- @return boolean: True if succeeded, nil on errors.
-function doc.command(flags, name, version)
-   if not name then
-      return nil, "Argument missing. "..util.see_help("doc")
-   end
-
-   name = util.adjust_name_and_namespace(name, flags)
+function doc.command(args)
+   local name = util.adjust_name_and_namespace(args.rock, args)
+   local version = args.version
    local query = queries.new(name, version)
-   local iname, iversion, repo = search.pick_installed_rock(query, flags["tree"])
+   local iname, iversion, repo = search.pick_installed_rock(query, args.tree)
    if not iname then
       util.printout(name..(version and " "..version or "").." is not installed. Looking for it in the rocks servers...")
       return try_to_open_homepage(name, version)
@@ -75,7 +73,7 @@ function doc.command(flags, name, version)
    if not rockspec then return nil,err end
    local descript = rockspec.description or {}
 
-   if flags["home"] then
+   if args.home then
       return show_homepage(descript.homepage, name, version)
    end
 
@@ -91,7 +89,7 @@ function doc.command(flags, name, version)
       end
    end
    if not docdir then
-      if descript.homepage and not flags["list"] then
+      if descript.homepage and not args.list then
          util.printout("Local documentation directory not found -- opening "..descript.homepage.." ...")
          fs.browser(descript.homepage)
          return true
@@ -105,7 +103,7 @@ function doc.command(flags, name, version)
    local extensions = { htmlpatt, "%.md$", "%.txt$",  "%.textile$", "" }
    local basenames = { "index", "readme", "manual" }
    
-   local porcelain = flags["porcelain"]
+   local porcelain = args.porcelain
    if #files > 0 then
       util.title("Documentation files for "..name.." "..version, porcelain)
       if porcelain then
@@ -120,7 +118,7 @@ function doc.command(flags, name, version)
       end
    end
    
-   if flags["list"] then
+   if args.list then
       return true
    end
    
diff --git a/src/luarocks/cmd/download.lua b/src/luarocks/cmd/download.lua
index 50c10c0c..5032d580 100644
--- a/src/luarocks/cmd/download.lua
+++ b/src/luarocks/cmd/download.lua
@@ -6,42 +6,44 @@ local cmd_download = {}
 local util = require("luarocks.util")
 local download = require("luarocks.download")
 
-cmd_download.help_summary = "Download a specific rock file from a rocks server."
-cmd_download.help_arguments = "[--all] [--arch=<arch> | --source | --rockspec] [<name> [<version>]]"
-cmd_download.help = [[
---all          Download all files if there are multiple matches.
---source       Download .src.rock if available.
---rockspec     Download .rockspec if available.
---arch=<arch>  Download rock for a specific architecture.
-]]
+function cmd_download.add_to_parser(parser)
+   local cmd = parser:command("download", "Download a specific rock file from a rocks server.", util.see_also())
+
+   cmd:argument("name", "Name of the rock.")
+      :args("?")
+   cmd:argument("version", "Version of the rock.")
+      :args("?")
+
+   cmd:flag("--all", "Download all files if there are multiple matches.")
+   cmd:mutex(
+      cmd:flag("--source", "Download .src.rock if available."),
+      cmd:flag("--rockspec", "Download .rockspec if available."),
+      cmd:option("--arch", "Download rock for a specific architecture."))
+end
 
 --- Driver function for the "download" command.
--- @param name string: a rock name.
--- @param version string or nil: if the name of a package is given, a
--- version may also be passed.
 -- @return boolean or (nil, string): true if successful or nil followed
 -- by an error message.
-function cmd_download.command(flags, name, version)
-   assert(type(version) == "string" or not version)
-   if type(name) ~= "string" and not flags["all"] then
+function cmd_download.command(args)
+   if not args.name and not args.all then
       return nil, "Argument missing. "..util.see_help("download")
    end
 
-   name = util.adjust_name_and_namespace(name, flags)
+   local name = util.adjust_name_and_namespace(args.name, args)
 
-   if not name then name, version = "", "" end
+   if not name then name, args.version = "", "" end
 
    local arch
 
-   if flags["source"] then
+   if args.source then
       arch = "src"
-   elseif flags["rockspec"] then
+   elseif args.rockspec then
       arch = "rockspec"
-   elseif flags["arch"] then
-      arch = flags["arch"]
+   elseif args.arch then
+      arch = args.arch
    end
    
-   local dl, err = download.download(arch, name:lower(), version, flags["all"])
+   local dl, err = download.download(arch, name:lower(), args.version, args.all)
    return dl and true, err
 end
 
diff --git a/src/luarocks/cmd/help.lua b/src/luarocks/cmd/help.lua
deleted file mode 100644
index b3d937e1..00000000
--- a/src/luarocks/cmd/help.lua
+++ /dev/null
@@ -1,139 +0,0 @@
-
---- Module implementing the LuaRocks "help" command.
--- This is a generic help display module, which
--- uses a global table called "commands" to find commands
--- to show help for; each command should be represented by a
--- table containing "help" and "help_summary" fields.
-local help = {}
-
-local util = require("luarocks.util")
-local cfg = require("luarocks.core.cfg")
-local dir = require("luarocks.dir")
-local fs = require("luarocks.fs")
-
-local program = util.this_program("luarocks")
-
-help.help_summary = "Help on commands. Type '"..program.." help <command>' for more."
-
-help.help_arguments = "[<command>]"
-help.help = [[
-<command> is the command to show help for.
-]]
-
-local function print_banner()
-   util.printout("\nLuaRocks "..cfg.program_version..", the Lua package manager")
-end
-
-local function print_section(section)
-   util.printout("\n"..section)
-end
-
-local function get_status(status)
-   if status then
-      return "ok"
-   else
-      return "not found"
-   end
-end
-
---- Driver function for the "help" command.
--- @param command string or nil: command to show help for; if not
--- given, help summaries for all commands are shown.
--- @return boolean or (nil, string): true if there were no errors
--- or nil and an error message if an invalid command was requested.
-function help.command(description, commands, command)
-   assert(type(description) == "string")
-   assert(type(commands) == "table")
-
-   if not command then
-      print_banner()
-      print_section("NAME")
-      util.printout("\t"..program..[[ - ]]..description)
-      print_section("SYNOPSIS")
-      util.printout("\t"..program..[[ [<flags...>] [VAR=VALUE]... <command> [<argument>] ]])
-      print_section("GENERAL OPTIONS")
-      util.printout([[
-        These apply to all commands, as appropriate:
-
-        --dev                  Enable the sub-repositories in rocks servers
-                               for rockspecs of in-development versions
-        --server=<server>      Fetch rocks/rockspecs from this server
-                               (takes priority over config file)
-        --only-server=<server> Fetch rocks/rockspecs from this server only
-                               (overrides any entries in the config file)
-        --only-sources=<url>   Restrict downloads to paths matching the
-                               given URL.
-        --lua-dir=<prefix>     Which Lua installation to use.
-        --lua-version=<ver>    Which Lua version to use.
-        --tree=<tree>          Which tree to operate on.
-        --local                Use the tree in the user's home directory.
-                               To enable it, see ']]..program..[[ help path'.
-        --global               Use the system tree when `local_by_default` is `true`.
-        --verbose              Display verbose output of commands executed.
-        --timeout=<seconds>    Timeout on network operations, in seconds.
-                               0 means no timeout (wait forever).
-                               Default is ]]..tostring(cfg.connection_timeout)..[[.]])
-      print_section("VARIABLES")
-      util.printout([[
-        Variables from the "variables" table of the configuration file
-        can be overridden with VAR=VALUE assignments.]])
-      print_section("COMMANDS")
-      for name, modname in util.sortedpairs(commands) do
-         local cmd = require(modname)
-         util.printout("", name)
-         util.printout("\t", cmd.help_summary)
-      end
-      print_section("CONFIGURATION")
-      util.printout("\tLua version: " .. cfg.lua_version)
-      local ljv = util.get_luajit_version()
-      if ljv then
-         util.printout("\tLuaJIT version: " .. ljv)
-      end
-      util.printout()
-      util.printout("\tConfiguration files:")
-      local conf = cfg.config_files
-      util.printout("\t\tSystem  : ".. fs.absolute_name(conf.system.file) .. " (" .. get_status(conf.system.found) ..")")
-      if conf.user.file then
-         util.printout("\t\tUser    : ".. fs.absolute_name(conf.user.file) .. " (" .. get_status(conf.user.found) ..")")
-      else
-         util.printout("\t\tUser    : disabled in this LuaRocks installation.")
-      end
-      if conf.project then
-         util.printout("\t\tProject : ".. fs.absolute_name(conf.project.file) .. " (" .. get_status(conf.project.found) ..")")
-      end
-      util.printout()
-      util.printout("\tRocks trees in use: ")
-      for _, tree in ipairs(cfg.rocks_trees) do
-         if type(tree) == "string" then
-            util.printout("\t\t"..fs.absolute_name(tree))
-         else
-            local name = tree.name and " (\""..tree.name.."\")" or ""
-            util.printout("\t\t"..fs.absolute_name(tree.root)..name)
-         end
-      end
-      util.printout()
-   else
-      command = command:gsub("-", "_")
-      local cmd = commands[command] and require(commands[command])
-      if cmd then
-         local arguments = cmd.help_arguments or "<argument>"
-         print_banner()
-         print_section("NAME")
-         util.printout("\t"..program.." "..command.." - "..cmd.help_summary)
-         print_section("SYNOPSIS")
-         util.printout("\t"..program.." "..command.." "..arguments)
-         print_section("DESCRIPTION")
-         util.printout("",(cmd.help:gsub("\n","\n\t"):gsub("\n\t$","")))
-         print_section("SEE ALSO")
-         if cmd.help_see_also then
-            util.printout(cmd.help_see_also)
-         end
-         util.printout("","'"..program.." help' for general options and configuration.\n")
-      else
-         return nil, "Unknown command: "..command
-      end
-   end
-   return true
-end
-
-return help
diff --git a/src/luarocks/cmd/init.lua b/src/luarocks/cmd/init.lua
index 60aa4f82..5f269e22 100644
--- a/src/luarocks/cmd/init.lua
+++ b/src/luarocks/cmd/init.lua
@@ -10,27 +10,17 @@ local util = require("luarocks.util")
 local persist = require("luarocks.persist")
 local write_rockspec = require("luarocks.cmd.write_rockspec")
 
-init.help_summary = "Initialize a directory for a Lua project using LuaRocks."
-init.help_arguments = "[<name> [<version>]]"
-init.help = [[
-<name> is the project name.
-<version> is an optional project version.
-
---reset                  Delete .luarocks/config-5.x.lua and ./lua
-                         and generate new ones.
-
-Options for specifying rockspec data:
-
---license="<string>"     A license string, such as "MIT/X11" or "GNU GPL v3".
---summary="<txt>"        A short one-line description summary.
---detailed="<txt>"       A longer description string.
---homepage=<url>         Project homepage.
---lua-versions=<ver>     Supported Lua versions. Accepted values are "5.1", "5.2",
-                         "5.3", "5.1,5.2", "5.2,5.3", or "5.1,5.2,5.3".
---rockspec-format=<ver>  Rockspec format version, such as "1.0" or "1.1".
---lib=<lib>[,<lib>]      A comma-separated list of libraries that C files need to
-                         link to.
-]]
+function init.add_to_parser(parser)
+   local cmd = parser:command("init", "Initialize a directory for a Lua project using LuaRocks.", util.see_also())
+
+   cmd:argument("name", "The project name.")
+      :args("?")
+   cmd:argument("version", "An optional project version.")
+      :args("?")
+   cmd:flag("--reset", "Delete .luarocks/config-5.x.lua and ./lua and generate new ones.")
+
+   cmd:group("Options for specifying rockspec data", write_rockspec.cmd_options(cmd))
+end
 
 local function write_gitignore(entries)
    local gitignore = ""
@@ -53,18 +43,18 @@ end
 
 --- Driver function for "init" command.
 -- @return boolean: True if succeeded, nil on errors.
-function init.command(flags, name, version)
+function init.command(args)
 
    local pwd = fs.current_dir()
 
-   if not name then
-      name = dir.base_name(pwd)
-      if name == "/" then
+   if not args.name then
+      args.name = dir.base_name(pwd)
+      if args.name == "/" then
          return nil, "When running from the root directory, please specify the <name> argument"
       end
    end
 
-   util.title("Initializing project '" .. name .. "' for Lua " .. cfg.lua_version .. " ...")
+   util.title("Initializing project '" .. args.name .. "' for Lua " .. cfg.lua_version .. " ...")
 
    util.printout("Checking your Lua installation ...")
    if not cfg.lua_found then
@@ -84,7 +74,9 @@ function init.command(flags, name, version)
    end
 
    if not has_rockspec then
-      local ok, err = write_rockspec.command(flags, name, version or "dev", pwd)
+      args.version = args.version or "dev"
+      args.location = pwd
+      local ok, err = write_rockspec.command(args)
       if not ok then
          util.printerr(err)
       end
@@ -101,7 +93,7 @@ function init.command(flags, name, version)
    fs.make_dir(".luarocks")
    local config_file = ".luarocks/config-" .. cfg.lua_version .. ".lua"
 
-   if flags["reset"] then
+   if args.reset then
       fs.delete(lua_wrapper)
       fs.delete(config_file)
    end
diff --git a/src/luarocks/cmd/install.lua b/src/luarocks/cmd/install.lua
index d1d7bf6c..4020918e 100644
--- a/src/luarocks/cmd/install.lua
+++ b/src/luarocks/cmd/install.lua
@@ -16,32 +16,35 @@ local cfg = require("luarocks.core.cfg")
 local cmd = require("luarocks.cmd")
 local dir = require("luarocks.dir")
 
-install.help_summary = "Install a rock."
-
-install.help_arguments = "{<rock>|<name> [<version>]}"
-
-install.help = [[
-Argument may be the name of a rock to be fetched from a repository
-or a filename of a locally available rock.
-
---keep              Do not remove previously installed versions of the
-                    rock after installing a new one. This behavior can
-                    be made permanent by setting keep_other_versions=true
-                    in the configuration file.
-
---only-deps         Installs only the dependencies of the rock.
-
---no-doc            Installs the rock without its documentation.
-
---verify            Verify signature of the rock being installed.
-                    If rock is being downloaded, LuaRocks will attempt
-                    to download the signature as well. If the rock is
-                    local, the signature file should be in the same
-                    directory.
-                    You need the signer’s public key in your local
-                    keyring for this option to work properly.
-
-]]..util.deps_mode_help()
+function install.add_to_parser(parser)
+   local cmd = parser:command("install", "Install a rock.", util.see_also())
+
+   cmd:argument("rock", "The name of a rock to be fetched from a repository "..
+      "or a filename of a locally available rock.")
+   cmd:argument("version", "Version of the rock.")
+      :args("?")
+
+   cmd:flag("--keep", "Do not remove previously installed versions of the "..
+      "rock after building a new one. This behavior can be made permanent by "..
+      "setting keep_other_versions=true in the configuration file.")
+   cmd:flag("--force", "If --keep is not specified, force removal of "..
+      "previously installed versions if it would break dependencies.")
+   cmd:flag("--force-fast", "Like --force, but performs a forced removal "..
+      "without reporting dependency issues.")
+   cmd:flag("--only-deps", "Installs only the dependencies of the rock.")
+   cmd:flag("--no-doc", "Installs the rock without its documentation.")
+   cmd:flag("--verify", "Verify signature of the rockspec or src.rock being "..
+      "built. If the rockspec or src.rock is being downloaded, LuaRocks will "..
+      "attempt to download the signature as well. Otherwise, the signature "..
+      "file should be already available locally in the same directory.\n"..
+      "You need the signer’s public key in your local keyring for this "..
+      "option to work properly.")
+   util.deps_mode_option(cmd)
+   -- luarocks build options
+   parser:flag("--pack-binary-rock"):hidden(true)
+   parser:flag("--branch"):hidden(true)
+   parser:flag("--sign"):hidden(true)
+end
 
 install.opts = util.opts_table("install.opts", {
    namespace = "string?",
@@ -208,51 +211,46 @@ local function install_rock_file(filename, opts)
 end
 
 --- Driver function for the "install" command.
--- @param name string: name of a binary rock. If an URL or pathname
--- to a binary rock is given, fetches and installs it. If a rockspec or a
--- source rock is given, forwards the request to the "build" command.
+-- If an URL or pathname to a binary rock is given, fetches and installs it.
+-- If a rockspec or a source rock is given, forwards the request to the "build"
+-- command.
 -- If a package name is given, forwards the request to "search" and,
 -- if returned a result, installs the matching rock.
--- @param version string: When passing a package name, a version number
--- may also be given.
 -- @return boolean or (nil, string, exitcode): True if installation was
 -- successful, nil and an error message otherwise. exitcode is optionally returned.
-function install.command(flags, name, version)
-   if type(name) ~= "string" then
-      return nil, "Argument missing. "..util.see_help("install")
-   end
-
-   name = util.adjust_name_and_namespace(name, flags)
+function install.command(args)
+   args.rock = util.adjust_name_and_namespace(args.rock, args)
 
-   local ok, err = fs.check_command_permissions(flags)
+   local ok, err = fs.check_command_permissions(args)
    if not ok then return nil, err, cmd.errorcodes.PERMISSIONDENIED end
 
-   if name:match("%.rockspec$") or name:match("%.src%.rock$") then
+   if args.rock:match("%.rockspec$") or args.rock:match("%.src%.rock$") then
       local build = require("luarocks.cmd.build")
-      return build.command(flags, name)
-   elseif name:match("%.rock$") then
-      local deps_mode = deps.get_deps_mode(flags)
+      return build.command(args)
+   elseif args.rock:match("%.rock$") then
+      local deps_mode = deps.get_deps_mode(args)
       local opts = install.opts({
-         namespace = flags["namespace"],
-         keep = not not flags["keep"],
-         force = not not flags["force"],
-         force_fast = not not flags["force-fast"],
-         no_doc = not not flags["no-doc"],
+         namespace = args.namespace,
+         keep = not not args.keep,
+         force = not not args.force,
+         force_fast = not not args.force_fast,
+         no_doc = not not args.no_doc,
          deps_mode = deps_mode,
-         verify = not not flags["verify"],
+         verify = not not args.verify,
       })
-      if flags["only-deps"] then
-         return install_rock_file_deps(name, opts)
+      if args.only_deps then
+         return install_rock_file_deps(args.rock, opts)
       else
-         return install_rock_file(name, opts)
+         return install_rock_file(args.rock, opts)
       end
    else
-      local url, err = search.find_suitable_rock(queries.new(name:lower(), version), true)
+      local url, err = search.find_suitable_rock(queries.new(args.rock:lower(), args.version), true)
       if not url then
          return nil, err
       end
       util.printout("Installing "..url)
-      return install.command(flags, url)
+      args.rock = url
+      return install.command(args)
    end
 end
 
diff --git a/src/luarocks/cmd/lint.lua b/src/luarocks/cmd/lint.lua
index c9ea45ea..20c842ff 100644
--- a/src/luarocks/cmd/lint.lua
+++ b/src/luarocks/cmd/lint.lua
@@ -7,24 +7,21 @@ local util = require("luarocks.util")
 local download = require("luarocks.download")
 local fetch = require("luarocks.fetch")
 
-lint.help_summary = "Check syntax of a rockspec."
-lint.help_arguments = "<rockspec>"
-lint.help = [[
-This is a utility function that checks the syntax of a rockspec.
-
-It returns success or failure if the text of a rockspec is
-syntactically correct.
-]]
-
-function lint.command(flags, input)
-   if not input then
-      return nil, "Argument missing. "..util.see_help("lint")
-   end
-   
-   local filename = input
-   if not input:match(".rockspec$") then
+function lint.add_to_parser(parser)
+   local cmd = parser:command("lint", "Check syntax of a rockspec.\n\n"..
+      "Returns success if the text of the rockspec is syntactically correct, else failure.",
+      util.see_also())
+      :summary("Check syntax of a rockspec.")
+
+   cmd:argument("rockspec", "The rockspec to check.")
+end
+
+function lint.command(args)
+
+   local filename = args.rockspec
+   if not filename:match(".rockspec$") then
       local err
-      filename, err = download.download("rockspec", input:lower())
+      filename, err = download.download("rockspec", filename:lower())
       if not filename then
          return nil, err
       end
diff --git a/src/luarocks/cmd/list.lua b/src/luarocks/cmd/list.lua
index 5e5cfac8..cac5cd8a 100644
--- a/src/luarocks/cmd/list.lua
+++ b/src/luarocks/cmd/list.lua
@@ -10,16 +10,18 @@ local cfg = require("luarocks.core.cfg")
 local util = require("luarocks.util")
 local path = require("luarocks.path")
 
-list.help_summary = "List currently installed rocks."
-list.help_arguments = "[--porcelain] <filter>"
-list.help = [[
-<filter> is a substring of a rock name to filter by.
+function list.add_to_parser(parser)
+   local cmd = parser:command("list", "List currently installed rocks.", util.see_also())
 
---outdated    List only rocks for which there is a
-              higher version available in the rocks server.
+   cmd:argument("filter", "A substring of a rock name to filter by.")
+      :args("?")
+   cmd:argument("version", "Rock version to filter by.")
+      :args("?")
 
---porcelain   Produce machine-friendly output.
-]]
+   cmd:flag("--outdated", "List only rocks for which there is a higher "..
+      "version available in the rocks server.")
+   cmd:flag("--porcelain", "Produce machine-friendly output.")
+end
 
 local function check_outdated(trees, query)
    local results_installed = {}
@@ -65,20 +67,18 @@ local function list_outdated(trees, query, porcelain)
 end
 
 --- Driver function for "list" command.
--- @param filter string or nil: A substring of a rock name to filter by.
--- @param version string or nil: a version may also be passed.
 -- @return boolean: True if succeeded, nil on errors.
-function list.command(flags, filter, version)
-   local query = queries.new(filter and filter:lower() or "", version, true)
+function list.command(args)
+   local query = queries.new(args.filter and args.filter:lower() or "", args.version, true)
    local trees = cfg.rocks_trees
    local title = "Rocks installed for Lua "..cfg.lua_version
-   if flags["tree"] then
-      trees = { flags["tree"] }
-      title = title .. " in " .. flags["tree"]
+   if args.tree then
+      trees = { args.tree }
+      title = title .. " in " .. args.tree
    end
    
-   if flags["outdated"] then
-      return list_outdated(trees, query, flags["porcelain"])
+   if args.outdated then
+      return list_outdated(trees, query, args.porcelain)
    end
    
    local results = {}
@@ -88,8 +88,8 @@ function list.command(flags, filter, version)
          util.warning(err)
       end
    end
-   util.title(title, flags["porcelain"])
-   search.print_result_tree(results, flags["porcelain"])
+   util.title(title, args.porcelain)
+   search.print_result_tree(results, args.porcelain)
    return true
 end
 
diff --git a/src/luarocks/cmd/make.lua b/src/luarocks/cmd/make.lua
index 4d813864..480ec48d 100644
--- a/src/luarocks/cmd/make.lua
+++ b/src/luarocks/cmd/make.lua
@@ -16,58 +16,61 @@ local deps = require("luarocks.deps")
 local writer = require("luarocks.manif.writer")
 local cmd = require("luarocks.cmd")
 
-make.help_summary = "Compile package in current directory using a rockspec."
-make.help_arguments = "[--pack-binary-rock] [<rockspec>]"
-make.help = [[
-Builds sources in the current directory, but unlike "build",
-it does not fetch sources, etc., assuming everything is 
-available in the current directory. If no argument is given,
-it looks for a rockspec in the current directory and in "rockspec/"
-and "rockspecs/" subdirectories, picking the rockspec with newest version
-or without version name. If rockspecs for different rocks are found
-or there are several rockspecs without version, you must specify which to use,
+function make.cmd_options(parser)
+   parser:flag("--pack-binary-rock", "Do not install rock. Instead, produce a "..
+      ".rock file with the contents of compilation in the current directory.")
+   parser:flag("--keep", "Do not remove previously installed versions of the "..
+      "rock after building a new one. This behavior can be made permanent by "..
+      "setting keep_other_versions=true in the configuration file.")
+   parser:flag("--force", "If --keep is not specified, force removal of "..
+      "previously installed versions if it would break dependencies.")
+   parser:flag("--force-fast", "Like --force, but performs a forced removal "..
+      "without reporting dependency issues.")
+   parser:option("--branch", "Override the `source.branch` field in the loaded "..
+      "rockspec. Allows to specify a different branch to fetch. Particularly "..
+      'for "dev" rocks.')
+      :argname("<name>")
+   parser:flag("--verify", "Verify signature of the rockspec or src.rock being "..
+      "built. If the rockspec or src.rock is being downloaded, LuaRocks will "..
+      "attempt to download the signature as well. Otherwise, the signature "..
+      "file should be already available locally in the same directory.\n"..
+      "You need the signer’s public key in your local keyring for this "..
+      "option to work properly.")
+   parser:flag("--sign", "To be used with --pack-binary-rock. Also produce a "..
+      "signature file for the generated .rock file.")
+   util.deps_mode_option(parser)
+end
+
+function make.add_to_parser(parser)
+   local cmd = parser:command("make", [[
+Builds sources in the current directory, but unlike "build", it does not fetch
+sources, etc., assuming everything is available in the current directory. If no
+argument is given, it looks for a rockspec in the current directory and in
+"rockspec/" and "rockspecs/" subdirectories, picking the rockspec with newest
+version or without version name. If rockspecs for different rocks are found or
+there are several rockspecs without version, you must specify which to use,
 through the command-line.
 
 This command is useful as a tool for debugging rockspecs. 
-To install rocks, you'll normally want to use the "install" and
-"build" commands. See the help on those for details.
+To install rocks, you'll normally want to use the "install" and "build"
+commands. See the help on those for details.
 
 NB: Use `luarocks install` with the `--only-deps` flag if you want to install
 only dependencies of the rockspec (see `luarocks help install`).
+]], util.see_also())
+      :summary("Compile package in current directory using a rockspec.")
 
---pack-binary-rock  Do not install rock. Instead, produce a .rock file
-                    with the contents of compilation in the current
-                    directory.
-
---keep              Do not remove previously installed versions of the
-                    rock after installing a new one. This behavior can
-                    be made permanent by setting keep_other_versions=true
-                    in the configuration file.
-
---branch=<name>     Override the `source.branch` field in the loaded
-                    rockspec. Allows to specify a different branch to 
-                    fetch. Particularly for "dev" rocks.
+   cmd:argument("rockspec", "Rockspec for the rock to build.")
+      :args("?")
 
---verify            Verify signature of the rockspec or src.rock being
-                    built. If the rockspec or src.rock is being downloaded,
-                    LuaRocks will attempt to download the signature as well.
-                    Otherwise, the signature file should be already
-                    available locally in the same directory.
-                    You need the signer’s public key in your local
-                    keyring for this option to work properly.
-
---sign              To be used with --pack-binary-rock. Also produce
-                    a signature file for the generated .rock file.
-
-]]
+   make.cmd_options(cmd)
+end
 
 --- Driver function for "make" command.
--- @param name string: A local rockspec.
 -- @return boolean or (nil, string, exitcode): True if build was successful; nil and an
 -- error message otherwise. exitcode is optionally returned.
-function make.command(flags, rockspec_filename)
-   assert(type(rockspec_filename) == "string" or not rockspec_filename)
-   
+function make.command(args)
+   local rockspec_filename = args.rockspec
    if not rockspec_filename then
       local err
       rockspec_filename, err = util.get_default_rockspec()
@@ -84,39 +87,39 @@ function make.command(flags, rockspec_filename)
       return nil, err
    end
 
-   local name = util.adjust_name_and_namespace(rockspec.name, flags)
+   local name = util.adjust_name_and_namespace(rockspec.name, args)
 
    local opts = build.opts({
       need_to_fetch = false,
       minimal_mode = true,
-      deps_mode = deps.get_deps_mode(flags),
+      deps_mode = deps.get_deps_mode(args),
       build_only_deps = false,
-      namespace = flags["namespace"],
-      branch = not not flags["branch"],
-      verify = not not flags["verify"],
+      namespace = args.namespace,
+      branch = not not args.branch,
+      verify = not not args.verify,
    })
 
-   if flags["sign"] and not flags["pack-binary-rock"] then
+   if args.sign and not args.pack_binary_rock then
       return nil, "In the make command, --sign is meant to be used only with --pack-binary-rock"
    end
 
-   if flags["pack-binary-rock"] then
-      return pack.pack_binary_rock(name, rockspec.version, flags["sign"], function()
+   if args.pack_binary_rock then
+      return pack.pack_binary_rock(name, rockspec.version, args.sign, function()
          return build.build_rockspec(rockspec, opts)
       end)
    else
-      local ok, err = fs.check_command_permissions(flags)
+      local ok, err = fs.check_command_permissions(args)
       if not ok then return nil, err, cmd.errorcodes.PERMISSIONDENIED end
       ok, err = build.build_rockspec(rockspec, opts)
       if not ok then return nil, err end
       local name, version = ok, err
 
-      if (not flags["keep"]) and not cfg.keep_other_versions then
-         local ok, err = remove.remove_other_versions(name, version, flags["force"], flags["force-fast"])
+      if (not args.keep) and not cfg.keep_other_versions then
+         local ok, err = remove.remove_other_versions(name, version, args.force, args.force_fast)
          if not ok then util.printerr(err) end
       end
 
-      writer.check_dependencies(nil, deps.get_deps_mode(flags))
+      writer.check_dependencies(nil, deps.get_deps_mode(args))
       return name, version
    end
 end
diff --git a/src/luarocks/cmd/new_version.lua b/src/luarocks/cmd/new_version.lua
index 19b5fa1e..62fb08f6 100644
--- a/src/luarocks/cmd/new_version.lua
+++ b/src/luarocks/cmd/new_version.lua
@@ -11,35 +11,46 @@ local fs = require("luarocks.fs")
 local dir = require("luarocks.dir")
 local type_rockspec = require("luarocks.type.rockspec")
 
-new_version.help_summary = "Auto-write a rockspec for a new version of a rock."
-new_version.help_arguments = "[--tag=<tag>] [--dir=<path>] [<package>|<rockspec>] [<new_version>] [<new_url>]"
-new_version.help = [[
-This is a utility function that writes a new rockspec, updating data
-from a previous one.
-
-If a package name is given, it downloads the latest rockspec from the
-default server. If a rockspec is given, it uses it instead. If no argument
-is given, it looks for a rockspec same way 'luarocks make' does.
-
-If the version number is not given and tag is passed using --tag,
-it is used as the version, with 'v' removed from beginning.
-Otherwise, it only increments the revision number of the given
-(or downloaded) rockspec.
-
-If a URL is given, it replaces the one from the old rockspec with the
-given URL. If a URL is not given and a new version is given, it tries
-to guess the new URL by replacing occurrences of the version number
-in the URL or tag. It also tries to download the new URL to determine
-the new MD5 checksum.
-
-If a tag is given, it replaces the one from the old rockspec. If there is
-an old tag but no new one passed, it is guessed in the same way URL is.
+function new_version.add_to_parser(parser)
+   local cmd = parser:command("new_version", [[
+This is a utility function that writes a new rockspec, updating data from a
+previous one.
+
+If a package name is given, it downloads the latest rockspec from the default
+server. If a rockspec is given, it uses it instead. If no argument is given, it
+looks for a rockspec same way 'luarocks make' does.
+
+If the version number is not given and tag is passed using --tag, it is used as
+the version, with 'v' removed from beginning.  Otherwise, it only increments the
+revision number of the given (or downloaded) rockspec.
+
+If a URL is given, it replaces the one from the old rockspec with the given URL.
+If a URL is not given and a new version is given, it tries to guess the new URL
+by replacing occurrences of the version number in the URL or tag. It also tries
+to download the new URL to determine the new MD5 checksum.
+
+If a tag is given, it replaces the one from the old rockspec. If there is an old
+tag but no new one passed, it is guessed in the same way URL is.
 
 If a directory is not given, it defaults to the current directory.
 
-WARNING: it writes the new rockspec to the given directory,
-overwriting the file if it already exists.
-]]
+WARNING: it writes the new rockspec to the given directory, overwriting the file
+if it already exists.]], util.see_also())
+      :summary("Auto-write a rockspec for a new version of a rock.")
+
+   parser:command("new-version"):hidden(true):action(function(args) args.command = "new_version" end)
+
+   cmd:argument("rock", "Package name or rockspec.")
+      :args("?")
+   cmd:argument("new_version", "New version of the rock.")
+      :args("?")
+   cmd:argument("new_url", "New URL of the rock.")
+      :args("?")
+
+   cmd:option("--dir", "Output directory for the new rockspec.")
+   cmd:option("--tag", "New SCM tag.")
+end
+
 
 local function try_replace(tbl, field, old, new)
    if not tbl[field] then
@@ -126,24 +137,23 @@ local function update_source_section(out_rs, url, tag, old_ver, new_ver)
    return true
 end
  
-function new_version.command(flags, input, version, url)
-   if not input then
+function new_version.command(args)
+   if not args.rock then
       local err
-      input, err = util.get_default_rockspec()
-      if not input then
+      args.rock, err = util.get_default_rockspec()
+      if not args.rock then
          return nil, err
       end
    end
-   assert(type(input) == "string")
    
    local filename, err
-   if input:match("rockspec$") then
-      filename, err = fetch.fetch_url(input)
+   if args.rock:match("rockspec$") then
+      filename, err = fetch.fetch_url(args.rock)
       if not filename then
          return nil, err
       end
    else
-      filename, err = download.download("rockspec", input:lower())
+      filename, err = download.download("rockspec", args.rock:lower())
       if not filename then
          return nil, err
       end
@@ -157,20 +167,20 @@ function new_version.command(flags, input, version, url)
    local old_ver, old_rev = valid_rs.version:match("(.*)%-(%d+)$")
    local new_ver, new_rev
 
-   if flags.tag and not version then
-      version = flags.tag:gsub("^v", "")
+   if args.tag and not args.new_version then
+      args.new_version = args.tag:gsub("^v", "")
    end
    
    local out_dir
-   if flags.dir then
-      out_dir = dir.normalize(flags.dir)
+   if args.dir then
+      out_dir = dir.normalize(args.dir)
    end
 
-   if version then
-      new_ver, new_rev = version:match("(.*)%-(%d+)$")
+   if args.new_version then
+      new_ver, new_rev = args.new_version:match("(.*)%-(%d+)$")
       new_rev = tonumber(new_rev)
       if not new_rev then
-         new_ver = version
+         new_ver = args.new_version
          new_rev = 1
       end
    else
@@ -183,7 +193,7 @@ function new_version.command(flags, input, version, url)
    local out_name = out_rs.package:lower()
    out_rs.version = new_rockver.."-"..new_rev
 
-   local ok, err = update_source_section(out_rs, url, flags.tag, old_ver, new_ver)
+   local ok, err = update_source_section(out_rs, args.new_url, args.tag, old_ver, new_ver)
    if not ok then return nil, err end
 
    if out_rs.build and out_rs.build.type == "module" then
diff --git a/src/luarocks/cmd/pack.lua b/src/luarocks/cmd/pack.lua
index 7781a3bd..fde8f875 100644
--- a/src/luarocks/cmd/pack.lua
+++ b/src/luarocks/cmd/pack.lua
@@ -8,39 +8,30 @@ local pack = require("luarocks.pack")
 local signing = require("luarocks.signing")
 local queries = require("luarocks.queries")
 
-cmd_pack.help_summary = "Create a rock, packing sources or binaries."
-cmd_pack.help_arguments = "{<rockspec>|<name> [<version>]}"
-cmd_pack.help = [[
---sign     Produce a signature file as well.
+function cmd_pack.add_to_parser(parser)
+   local cmd = parser:command("pack", "Create a rock, packing sources or binaries.", util.see_also())
 
-Argument may be a rockspec file, for creating a source rock,
-or the name of an installed package, for creating a binary rock.
-In the latter case, the app version may be given as a second
-argument.
-]]
+   cmd:argument("rock", "A rockspec file, for creating a source rock, or the "..
+      "name of an installed package, for creating a binary rock.")
+   cmd:argument("version", "A version may be given if the first argument is a rock name.")
+      :args("?")
+
+   cmd:flag("--sign", "Produce a signature file as well.")
+end
 
 --- Driver function for the "pack" command.
--- @param arg string:  may be a rockspec file, for creating a source rock,
--- or the name of an installed package, for creating a binary rock.
--- @param version string or nil: if the name of a package is given, a
--- version may also be passed.
 -- @return boolean or (nil, string): true if successful or nil followed
 -- by an error message.
-function cmd_pack.command(flags, arg, version)
-   assert(type(version) == "string" or not version)
-   if type(arg) ~= "string" then
-      return nil, "Argument missing. "..util.see_help("pack")
-   end
-
+function cmd_pack.command(args)
    local file, err
-   if arg:match(".*%.rockspec") then
-      file, err = pack.pack_source_rock(arg)
+   if args.rock:match(".*%.rockspec") then
+      file, err = pack.pack_source_rock(args.rock)
    else
-      local name = util.adjust_name_and_namespace(arg, flags)
-      local query = queries.new(name, version)
-      file, err = pack.pack_installed_rock(query, flags["tree"])
+      local name = util.adjust_name_and_namespace(args.rock, args)
+      local query = queries.new(name, args.version)
+      file, err = pack.pack_installed_rock(query, args.tree)
    end
-   return pack.report_and_sign_local_file(file, err, flags["sign"])
+   return pack.report_and_sign_local_file(file, err, args.sign)
 end
 
 return cmd_pack
diff --git a/src/luarocks/cmd/path.lua b/src/luarocks/cmd/path.lua
index bb383ad9..b1da4c0b 100644
--- a/src/luarocks/cmd/path.lua
+++ b/src/luarocks/cmd/path.lua
@@ -7,48 +7,45 @@ local util = require("luarocks.util")
 local cfg = require("luarocks.core.cfg")
 local fs = require("luarocks.fs")
 
-path_cmd.help_summary = "Return the currently configured package path."
-path_cmd.help_arguments = ""
-path_cmd.help = [[
+function path_cmd.add_to_parser(parser)
+   local cmd = parser:command("path", [[
 Returns the package path currently configured for this installation
 of LuaRocks, formatted as shell commands to update LUA_PATH and LUA_CPATH. 
 
---no-bin       Do not export the PATH variable
-
---append       Appends the paths to the existing paths. Default is to prefix
-               the LR paths to the existing paths.
-
---lr-path      Exports the Lua path (not formatted as shell command)
-
---lr-cpath     Exports the Lua cpath (not formatted as shell command)
-
---lr-bin       Exports the system path (not formatted as shell command)
-
-
 On Unix systems, you may run: 
   eval `luarocks path`
 And on Windows: 
-  luarocks path > "%temp%\_lrp.bat" && call "%temp%\_lrp.bat" && del "%temp%\_lrp.bat"
-]]
+  luarocks path > "%temp%\_lrp.bat" && call "%temp%\_lrp.bat" && del "%temp%\_lrp.bat"]],
+  util.see_also())
+      :summary("Return the currently configured package path.")
+
+   cmd:flag("--no-bin", "Do not export the PATH variable.")
+   cmd:flag("--append", "Appends the paths to the existing paths. Default is "..
+      "to prefix the LR paths to the existing paths.")
+   cmd:flag("--lr-path", "Exports the Lua path (not formatted as shell command).")
+   cmd:flag("--lr-cpath", "Exports the Lua cpath (not formatted as shell command).")
+   cmd:flag("--lr-bin", "Exports the system path (not formatted as shell command).")
+   cmd:flag("--bin"):hidden(true)
+end
 
 --- Driver function for "path" command.
 -- @return boolean This function always succeeds.
-function path_cmd.command(flags)
-   local lr_path, lr_cpath, lr_bin = cfg.package_paths(flags["tree"])
+function path_cmd.command(args)
+   local lr_path, lr_cpath, lr_bin = cfg.package_paths(args.tree)
    local path_sep = cfg.export_path_separator
 
-   if flags["lr-path"] then
+   if args.lr_path then
       util.printout(util.cleanup_path(lr_path, ';', cfg.lua_version))
       return true
-   elseif flags["lr-cpath"] then
+   elseif args.lr_cpath then
       util.printout(util.cleanup_path(lr_cpath, ';', cfg.lua_version))
       return true
-   elseif flags["lr-bin"] then
+   elseif args.lr_bin then
       util.printout(util.cleanup_path(lr_bin, path_sep))
       return true
    end
    
-   if flags["append"] then
+   if args.append then
       lr_path = package.path .. ";" .. lr_path
       lr_cpath = package.cpath .. ";" .. lr_cpath
       lr_bin = os.getenv("PATH") .. path_sep .. lr_bin
@@ -60,10 +57,10 @@ function path_cmd.command(flags)
    
    local lpath_var, lcpath_var = util.lua_path_variables()
 
-   util.printout(fs.export_cmd(lpath_var, util.cleanup_path(lr_path, ';', cfg.lua_version, flags["append"])))
-   util.printout(fs.export_cmd(lcpath_var, util.cleanup_path(lr_cpath, ';', cfg.lua_version, flags["append"])))
-   if not flags["no-bin"] then
-      util.printout(fs.export_cmd("PATH", util.cleanup_path(lr_bin, path_sep, nil, flags["append"])))
+   util.printout(fs.export_cmd(lpath_var, util.cleanup_path(lr_path, ';', cfg.lua_version)))
+   util.printout(fs.export_cmd(lcpath_var, util.cleanup_path(lr_cpath, ';', cfg.lua_version)))
+   if not args.no_bin then
+      util.printout(fs.export_cmd("PATH", util.cleanup_path(lr_bin, path_sep)))
    end
    return true
 end
diff --git a/src/luarocks/cmd/purge.lua b/src/luarocks/cmd/purge.lua
index 98b76a0f..b71baa7c 100644
--- a/src/luarocks/cmd/purge.lua
+++ b/src/luarocks/cmd/purge.lua
@@ -15,24 +15,27 @@ local remove = require("luarocks.remove")
 local queries = require("luarocks.queries")
 local cmd = require("luarocks.cmd")
 
-purge.help_summary = "Remove all installed rocks from a tree."
-purge.help_arguments = "--tree=<tree> [--old-versions]"
-purge.help = [[
+function purge.add_to_parser(parser)
+   local cmd = parser:command("purge", [[
 This command removes rocks en masse from a given tree.
 By default, it removes all rocks from a tree.
 
-The --tree argument is mandatory: luarocks purge does not
-assume a default tree.
+The --tree option is mandatory: luarocks purge does not assume a default tree.]],
+   util.see_also())
+      :summary("Remove all installed rocks from a tree.")
 
---old-versions  Keep the highest-numbered version of each
-                rock and remove the other ones. By default
-                it only removes old versions if they are
-                not needed as dependencies. This can be
-                overridden with the flag --force.
-]]
+   cmd:flag("--old-versions", "Keep the highest-numbered version of each "..
+      "rock and remove the other ones. By default it only removes old "..
+      "versions if they are not needed as dependencies. This can be "..
+      "overridden with the flag --force.")
+   cmd:flag("--force", "If --old-versions is specified, force removal of "..
+      "previously installed versions if it would break dependencies.")
+   cmd:flag("--force-fast", "Like --force, but performs a forced removal "..
+      "without reporting dependency issues.")
+end
 
-function purge.command(flags)
-   local tree = flags["tree"]
+function purge.command(args)
+   local tree = args.tree
 
    if type(tree) ~= "string" then
       return nil, "The --tree argument is mandatory. "..util.see_help("purge")
@@ -43,21 +46,21 @@ function purge.command(flags)
       return nil, "Directory not found: "..tree
    end
 
-   local ok, err = fs.check_command_permissions(flags)
+   local ok, err = fs.check_command_permissions(args)
    if not ok then return nil, err, cmd.errorcodes.PERMISSIONDENIED end
 
    search.local_manifest_search(results, path.rocks_dir(tree), queries.all())
 
    local sort = function(a,b) return vers.compare_versions(b,a) end
-   if flags["old-versions"] then
+   if args.old_versions then
       sort = vers.compare_versions
    end
 
    for package, versions in util.sortedpairs(results) do
       for version, _ in util.sortedpairs(versions, sort) do
-         if flags["old-versions"] then
+         if args.old_versions then
             util.printout("Keeping "..package.." "..version.."...")
-            local ok, err = remove.remove_other_versions(package, version, flags["force"], flags["force-fast"])
+            local ok, err = remove.remove_other_versions(package, version, args.force, args.force_fast)
             if not ok then
                util.printerr(err)
             end
diff --git a/src/luarocks/cmd/remove.lua b/src/luarocks/cmd/remove.lua
index 5ddf7477..f29b0b7d 100644
--- a/src/luarocks/cmd/remove.lua
+++ b/src/luarocks/cmd/remove.lua
@@ -14,38 +14,38 @@ local writer = require("luarocks.manif.writer")
 local queries = require("luarocks.queries")
 local cmd = require("luarocks.cmd")
 
-cmd_remove.help_summary = "Uninstall a rock."
-cmd_remove.help_arguments = "[--force|--force-fast] <name> [<version>]"
-cmd_remove.help = [[
-Argument is the name of a rock to be uninstalled.
+function cmd_remove.add_to_parser(parser)
+   local cmd = parser:command("remove", [[
+Uninstall a rock.
+
 If a version is not given, try to remove all versions at once.
 Will only perform the removal if it does not break dependencies.
-To override this check and force the removal, use --force.
-To perform a forced removal without reporting dependency issues,
-use --force-fast.
+To override this check and force the removal, use --force or --force-fast.]],
+   util.see_also())
+      :summary("Uninstall a rock.")
+
+   cmd:argument("rock", "Name of the rock to be uninstalled.")
+   cmd:argument("version", "Version of the rock to uninstall.")
+      :args("?")
 
-]]..util.deps_mode_help()
+   cmd:flag("--force", "Force removal if it would break dependencies.")
+   cmd:flag("--force-fast", "Perform a forced removal without reporting dependency issues.")
+   util.deps_mode_option(cmd)
+end
 
 --- Driver function for the "remove" command.
--- @param name string: name of a rock. If a version is given, refer to
--- a specific version; otherwise, try to remove all versions.
--- @param version string: When passing a package name, a version number
--- may also be given.
 -- @return boolean or (nil, string, exitcode): True if removal was
 -- successful, nil and an error message otherwise. exitcode is optionally returned.
-function cmd_remove.command(flags, name, version)
-   if type(name) ~= "string" then
-      return nil, "Argument missing. "..util.see_help("remove")
-   end
-
-   name = util.adjust_name_and_namespace(name, flags)
+function cmd_remove.command(args)
+   local name = util.adjust_name_and_namespace(args.rock, args)
    
-   local deps_mode = flags["deps-mode"] or cfg.deps_mode
+   local deps_mode = args.deps_mode or cfg.deps_mode
    
-   local ok, err = fs.check_command_permissions(flags)
+   local ok, err = fs.check_command_permissions(args)
    if not ok then return nil, err, cmd.errorcodes.PERMISSIONDENIED end
    
    local rock_type = name:match("%.(rock)$") or name:match("%.(rockspec)$")
+   local version = args.version
    local filename = name
    if rock_type then
       name, version = path.parse_name(filename)
@@ -59,12 +59,12 @@ function cmd_remove.command(flags, name, version)
       return nil, "Could not find rock '"..name..(version and " "..version or "").."' in "..path.rocks_tree_to_string(cfg.root_dir)
    end
 
-   local ok, err = remove.remove_search_results(results, name, deps_mode, flags["force"], flags["force-fast"])
+   local ok, err = remove.remove_search_results(results, name, deps_mode, args.force, args.force_fast)
    if not ok then
       return nil, err
    end
 
-   writer.check_dependencies(nil, deps.get_deps_mode(flags))
+   writer.check_dependencies(nil, deps.get_deps_mode(args))
    return true
 end
 
diff --git a/src/luarocks/cmd/search.lua b/src/luarocks/cmd/search.lua
index 8f4d014e..f34cf7b9 100644
--- a/src/luarocks/cmd/search.lua
+++ b/src/luarocks/cmd/search.lua
@@ -9,17 +9,22 @@ local search = require("luarocks.search")
 local queries = require("luarocks.queries")
 local results = require("luarocks.results")
 
-cmd_search.help_summary = "Query the LuaRocks servers."
-cmd_search.help_arguments = "[--source] [--binary] { <name> [<version>] | --all }"
-cmd_search.help = [[
---source     Return only rockspecs and source rocks,
-             to be used with the "build" command.
---binary     Return only pure Lua and binary rocks (rocks that can be used
-             with the "install" command without requiring a C toolchain).
---all        List all contents of the server that are suitable to
-             this platform, do not filter by name.
---porcelain  Return a machine readable format.
-]]
+function cmd_search.add_to_parser(parser)
+   local cmd = parser:command("search", "Query the LuaRocks servers.", util.see_also())
+
+   cmd:argument("name", "Name of the rock to search for.")
+      :args("?")
+   cmd:argument("version", "Rock version to search for.")
+      :args("?")
+
+   cmd:flag("--source", "Return only rockspecs and source rocks, to be used "..
+      'with the "build" command.')
+   cmd:flag("--binary", "Return only pure Lua and binary rocks (rocks that "..
+      'can be used with the "install" command without requiring a C toolchain).')
+   cmd:flag("--all", "List all contents of the server that are suitable to "..
+      "this platform, do not filter by name.")
+   cmd:flag("--porcelain", "Return a machine readable format.")
+end
 
 --- Splits a list of search results into two lists, one for "source" results
 -- to be used with the "build" command, and one for "binary" results to be
@@ -45,33 +50,31 @@ local function split_source_and_binary_results(result_tree)
 end
 
 --- Driver function for "search" command.
--- @param name string: A substring of a rock name to search.
--- @param version string or nil: a version may also be passed.
 -- @return boolean or (nil, string): True if build was successful; nil and an
 -- error message otherwise.
-function cmd_search.command(flags, name, version)
+function cmd_search.command(args)
 
-   name = util.adjust_name_and_namespace(name, flags)
+   local name = util.adjust_name_and_namespace(args.name, args)
 
-   if flags["all"] then
-      name, version = "", nil
+   if args.all then
+      name, args.version = "", nil
    end
 
-   if type(name) ~= "string" and not flags["all"] then
+   if not args.name and not args.all then
       return nil, "Enter name and version or use --all. "..util.see_help("search")
    end
    
-   local query = queries.new(name:lower(), version, true)
+   local query = queries.new(name:lower(), args.version, true)
    local result_tree, err = search.search_repos(query)
-   local porcelain = flags["porcelain"]
-   local full_name = name .. (version and " " .. version or "")
+   local porcelain = args.porcelain
+   local full_name = name .. (args.version and " " .. args.version or "")
    util.title(full_name .. " - Search results for Lua "..cfg.lua_version..":", porcelain, "=")
    local sources, binaries = split_source_and_binary_results(result_tree)
-   if next(sources) and not flags["binary"] then
+   if next(sources) and not args.binary then
       util.title("Rockspecs and source rocks:", porcelain)
       search.print_result_tree(sources, porcelain)
    end
-   if next(binaries) and not flags["source"] then    
+   if next(binaries) and not args.source then
       util.title("Binary and pure-Lua rocks:", porcelain)
       search.print_result_tree(binaries, porcelain)
    end
diff --git a/src/luarocks/cmd/show.lua b/src/luarocks/cmd/show.lua
index 37c2c55e..db7aed54 100644
--- a/src/luarocks/cmd/show.lua
+++ b/src/luarocks/cmd/show.lua
@@ -13,24 +13,33 @@ local fetch = require("luarocks.fetch")
 local manif = require("luarocks.manif")
 local repos = require("luarocks.repos")
 
-show.help_summary = "Show information about an installed rock."
+function show.add_to_parser(parser)
+   local cmd = parser:command("show", [[
+Show information about an installed rock.
 
-show.help = [[
-<argument> is an existing package name.
 Without any flags, show all module information.
-With these flags, return only the desired information:
+With flags, return only the desired information.]], util.see_also())
+      :summary("Show information about an installed rock.")
 
---home       home page of project
---modules    all modules provided by this package as used by require()
---deps       packages this package depends on
---build-deps build-only dependencies for this package
---test-deps  dependencies for testing this package
---rockspec   the full path of the rockspec file
---mversion   the package version
---rock-tree  local tree where rock is installed
---rock-dir   data directory of the installed rock
-]]
+   cmd:argument("rock", "Name of an installed rock.")
+   cmd:argument("version", "Rock version.")
+      :args("?")
 
+   cmd:flag("--home", "Show home page of project.")
+   cmd:flag("--modules", "Show all modules provided by the package as used by require().")
+   cmd:flag("--deps", "Show packages the package depends on.")
+   cmd:flag("--build-deps", "Show build-only dependencies for the package.")
+   cmd:flag("--test-deps", "Show dependencies for testing the package.")
+   cmd:flag("--rockspec", "Show the full path of the rockspec file.")
+   cmd:flag("--mversion", "Show the package version.")
+   cmd:flag("--rock-tree", "Show local tree where rock is installed.")
+   cmd:flag("--rock-namespace", "Show rock namespace.")
+   cmd:flag("--rock-dir", "Show data directory of the installed rock.")
+   cmd:flag("--rock-license", "Show rock license.")
+   cmd:flag("--issues", "Show URL for project's issue tracker.")
+   cmd:flag("--labels", "List the labels of the rock.")
+   cmd:flag("--porcelain", "Produce machine-friendly output.")
+end
 
 local friendly_template = [[
           :
@@ -249,19 +258,14 @@ local function show_rock(template, namespace, name, version, rockspec, repo, min
 end
 
 --- Driver function for "show" command.
--- @param name or nil: an existing package name.
--- @param version string or nil: a version may also be passed.
 -- @return boolean: True if succeeded, nil on errors.
-function show.command(flags, name, version)
-   if not name then
-      return nil, "Argument missing. "..util.see_help("show")
-   end
-
-   name = util.adjust_name_and_namespace(name, flags)
+function show.command(args)
+   local name = util.adjust_name_and_namespace(args.rock, args)
+   local version = args.version
    local query = queries.new(name, version)
    
    local repo, repo_url
-   name, version, repo, repo_url = search.pick_installed_rock(query, flags["tree"])
+   name, version, repo, repo_url = search.pick_installed_rock(query, args.tree)
    if not name then
       return nil, version
    end
@@ -277,32 +281,32 @@ function show.command(flags, name, version)
    if not manifest then return nil,err end
    local minfo = manifest.repository[name][version][1]
 
-   if flags["rock-tree"] then util.printout(tree)
-   elseif flags["rock-namespace"] then util.printout(namespace)
-   elseif flags["rock-dir"] then util.printout(directory)
-   elseif flags["home"] then util.printout(descript.homepage)
-   elseif flags["rock-license"] then util.printout(descript.license)
-   elseif flags["issues"] then util.printout(descript.issues_url)
-   elseif flags["labels"] then util.printout(descript.labels and table.concat(descript.labels, "\n"))
-   elseif flags["modules"] then util.printout(keys_as_string(minfo.modules, "\n"))
-   elseif flags["deps"] then
+   if args.rock_tree then util.printout(tree)
+   elseif args.rock_namespace then util.printout(namespace)
+   elseif args.rock_dir then util.printout(directory)
+   elseif args.home then util.printout(descript.homepage)
+   elseif args.rock_license then util.printout(descript.license)
+   elseif args.issues then util.printout(descript.issues_url)
+   elseif args.labels then util.printout(descript.labels and table.concat(descript.labels, "\n"))
+   elseif args.modules then util.printout(keys_as_string(minfo.modules, "\n"))
+   elseif args.deps then
       for _, dep in ipairs(rockspec.dependencies) do
          util.printout(tostring(dep))
       end
-   elseif flags["build-deps"] then
+   elseif args.build_deps then
       for _, dep in ipairs(rockspec.build_dependencies) do
          util.printout(tostring(dep))
       end
-   elseif flags["test-deps"] then
+   elseif args.test_deps then
       for _, dep in ipairs(rockspec.test_dependencies) do
          util.printout(tostring(dep))
       end
-   elseif flags["rockspec"] then util.printout(rockspec_file)
-   elseif flags["mversion"] then util.printout(version)
-   elseif flags["porcelain"] then
-      show_rock(porcelain_template, namespace, name, version, rockspec, repo, minfo, flags["tree"])
+   elseif args.rockspec then util.printout(rockspec_file)
+   elseif args.mversion then util.printout(version)
+   elseif args.porcelain then
+      show_rock(porcelain_template, namespace, name, version, rockspec, repo, minfo, args.tree)
    else
-      show_rock(friendly_template, namespace, name, version, rockspec, repo, minfo, flags["tree"])
+      show_rock(friendly_template, namespace, name, version, rockspec, repo, minfo, args.tree)
    end
    return true
 end
diff --git a/src/luarocks/cmd/test.lua b/src/luarocks/cmd/test.lua
index 413a029c..7a1ffda2 100644
--- a/src/luarocks/cmd/test.lua
+++ b/src/luarocks/cmd/test.lua
@@ -6,42 +6,42 @@ local cmd_test = {}
 local util = require("luarocks.util")
 local test = require("luarocks.test")
 
-cmd_test.help_summary = "Run the test suite in the current directory."
-cmd_test.help_arguments = "[--test-type=<type>] [<rockspec>] [-- <args>]"
-cmd_test.help = [[
+function cmd_test.add_to_parser(parser)
+   local cmd = parser:command("test", [[
 Run the test suite for the Lua project in the current directory.
-If the first argument is a rockspec, it will use it to determine
-the parameters for running tests; otherwise, it will attempt to
-detect the rockspec.
 
-Any additional arguments are forwarded to the test suite. 
-To make sure that any flags passed in <args> are not interpreted
-as LuaRocks flags, use -- to separate LuaRocks arguments from
-test suite arguments.
+If the first argument is a rockspec, it will use it to determine the parameters
+for running tests; otherwise, it will attempt to detect the rockspec.
 
---test-type=<type>  Specify the test suite type manually if it was not
-                    specified in the rockspec and it could not be
-                    auto-detected.
+Any additional arguments are forwarded to the test suite.
+To make sure that test suite flags are not interpreted as LuaRocks flags, use --
+to separate LuaRocks arguments from test suite arguments.]],
+      util.see_also())
+      :summary("Run the test suite in the current directory.")
 
-]]..util.deps_mode_help()
+   cmd:argument("rockspec", "Project rockspec.")
+      :args("?")
+   cmd:argument("args", "Test suite arguments.")
+      :args("*")
 
-function cmd_test.command(flags, argument, ...)
-   assert(type(argument) == "string" or not argument)
-
-   local arguments = { ... }
+   cmd:option("--test-type", "Specify the test suite type manually if it was "..
+      "not specified in the rockspec and it could not be auto-detected.")
+      :argname("<type>")
+end
 
-   if argument and argument:match("rockspec$") then
-      return test.run_test_suite(argument, flags["test-type"], arguments)
+function cmd_test.command(args)
+   if args.rockspec and args.rockspec:match("rockspec$") then
+      return test.run_test_suite(args.rockspec, args.test_type, args.args)
    end
    
-   table.insert(arguments, 1, argument)
+   table.insert(args.args, 1, args.rockspec)
    
    local rockspec, err = util.get_default_rockspec()
    if not rockspec then
       return nil, err
    end
 
-   return test.run_test_suite(rockspec, flags["test-type"], arguments)
+   return test.run_test_suite(rockspec, args.test_type, args.args)
 end
 
 return cmd_test
diff --git a/src/luarocks/cmd/unpack.lua b/src/luarocks/cmd/unpack.lua
index 99263f49..fe0535e4 100644
--- a/src/luarocks/cmd/unpack.lua
+++ b/src/luarocks/cmd/unpack.lua
@@ -10,15 +10,20 @@ local build = require("luarocks.build")
 local dir = require("luarocks.dir")
 local search = require("luarocks.search")
 
-unpack.help_summary = "Unpack the contents of a rock."
-unpack.help_arguments = "[--force] {<rock>|<name> [<version>]}"
-unpack.help = [[
+function unpack.add_to_parser(parser)
+   local cmd = parser:command("unpack", [[
 Unpacks the contents of a rock in a newly created directory.
 Argument may be a rock file, or the name of a rock in a rocks server.
-In the latter case, the app version may be given as a second argument.
+In the latter case, the rock version may be given as a second argument.]],
+      util.see_also())
+      :summary("Unpack the contents of a rock.")
 
---force   Unpack files even if the output directory already exists.
-]]
+   cmd:argument("rock", "A rock file or the name of a rock.")
+   cmd:argument("version", "Rock version.")
+      :args("?")
+
+   cmd:flag("--force", "Unpack files even if the output directory already exists.")
+end
 
 --- Load a rockspec file to the given directory, fetches the source
 -- files specified in the rockspec, and unpack them inside the directory.
@@ -141,31 +146,22 @@ local function run_unpacker(file, force)
 end
 
 --- Driver function for the "unpack" command.
--- @param ns_name string: may be a rock filename, for unpacking a 
--- rock file or the name of a rock to be fetched and unpacked.
--- @param version string or nil: if the name of a package is given, a
--- version may also be passed.
 -- @return boolean or (nil, string): true if successful or nil followed
 -- by an error message.
-function unpack.command(flags, ns_name, version)
-   assert(type(version) == "string" or not version)
-   if type(ns_name) ~= "string" then
-      return nil, "Argument missing. "..util.see_help("unpack")
-   end
-
-   ns_name = util.adjust_name_and_namespace(ns_name, flags)
+function unpack.command(args)
+   local ns_name = util.adjust_name_and_namespace(args.rock, args)
 
    local url, err
    if ns_name:match(".*%.rock") or ns_name:match(".*%.rockspec") then
       url = ns_name
    else
-      url, err = search.find_src_or_rockspec(ns_name, version, true)
+      url, err = search.find_src_or_rockspec(ns_name, args.version, true)
       if not url then
          return nil, err
       end
    end
 
-   return run_unpacker(url, flags["force"])
+   return run_unpacker(url, args.force)
 end
 
 return unpack
diff --git a/src/luarocks/cmd/upload.lua b/src/luarocks/cmd/upload.lua
index b052500e..6e3877ba 100644
--- a/src/luarocks/cmd/upload.lua
+++ b/src/luarocks/cmd/upload.lua
@@ -8,37 +8,33 @@ local pack = require("luarocks.pack")
 local cfg = require("luarocks.core.cfg")
 local Api = require("luarocks.upload.api")
 
-upload.help_summary = "Upload a rockspec to the public rocks repository."
-upload.help_arguments = "[--skip-pack] [--api-key=<key>] [--force] <rockspec>"
-upload.help = [[
-<rockspec>       Pack a source rock file (.src.rock extension),
-                 upload rockspec and source rock to server.
-
---skip-pack      Do not pack and send source rock.
-
---api-key=<key>  Give it an API key. It will be stored for subsequent uses.
-
---temp-key=<key> Use the given a temporary API key in this invocation only.
-                 It will not be stored.
-
---force          Replace existing rockspec if the same revision of
-                 a module already exists. This should be used only 
-                 in case of upload mistakes: when updating a rockspec,
-                 increment the revision number instead.
-
---sign           Upload a signature file alongside each file as well.
-]]
+function upload.add_to_parser(parser)
+   local cmd = parser:command("upload", "Pack a source rock file (.src.rock extension) "..
+      "and upload it and the rockspec to the public rocks repository.", util.see_also())
+      :summary("Upload a rockspec to the public rocks repository.")
+
+   cmd:argument("rockspec", "Rockspec for the rock to upload.")
+
+   cmd:flag("--skip-pack", "Do not pack and send source rock.")
+   cmd:option("--api-key", "Pass an API key. It will be stored for subsequent uses.")
+      :argname("<key>")
+   cmd:option("--temp-key", "Use the given a temporary API key in this "..
+      "invocation only. It will not be stored.")
+      :argname("<key>")
+   cmd:flag("--force", "Replace existing rockspec if the same revision of a "..
+      "module already exists. This should be used only in case of upload "..
+      "mistakes: when updating a rockspec, increment the revision number "..
+      "instead.")
+   cmd:flag("--sign", "Upload a signature file alongside each file as well.")
+   cmd:flag("--debug"):hidden(true)
+end
 
 local function is_dev_version(version)
    return version:match("^dev") or version:match("^scm")
 end
 
-function upload.command(flags, fname)
-   if not fname then
-      return nil, "Missing rockspec. "..util.see_help("upload")
-   end
-
-   local api, err = Api.new(flags)
+function upload.command(args)
+   local api, err = Api.new(args)
    if not api then
       return nil, err
    end
@@ -46,12 +42,12 @@ function upload.command(flags, fname)
       api.debug = true
    end
 
-   local rockspec, err, errcode = fetch.load_rockspec(fname)
+   local rockspec, err, errcode = fetch.load_rockspec(args.rockspec)
    if err then
       return nil, err, errcode
    end
 
-   util.printout("Sending " .. tostring(fname) .. " ...")
+   util.printout("Sending " .. tostring(args.rockspec) .. " ...")
    local res, err = api:method("check_rockspec", {
       package = rockspec.package,
       version = rockspec.version
@@ -61,15 +57,15 @@ function upload.command(flags, fname)
    if not res.module then
       util.printout("Will create new module (" .. tostring(rockspec.package) .. ")")
    end
-   if res.version and not flags["force"] then
+   if res.version and not args.force then
       return nil, "Revision "..rockspec.version.." already exists on the server. "..util.see_help("upload")
    end
 
    local sigfname
    local rock_sigfname
 
-   if flags["sign"] then
-      sigfname, err = signing.sign_file(fname)
+   if args.sign then
+      sigfname, err = signing.sign_file(args.rockspec)
       if err then
          return nil, "Failed signing rockspec: " .. err
       end
@@ -77,13 +73,13 @@ function upload.command(flags, fname)
    end
 
    local rock_fname
-   if not flags["skip-pack"] and not is_dev_version(rockspec.version) then
+   if not args.skip_pack and not is_dev_version(rockspec.version) then
       util.printout("Packing " .. tostring(rockspec.package))
-      rock_fname, err = pack.pack_source_rock(fname)
+      rock_fname, err = pack.pack_source_rock(args.rockspec)
       if not rock_fname then
          return nil, err
       end
-      if flags["sign"] then
+      if args.sign then
          rock_sigfname, err = signing.sign_file(rock_fname)
          if err then
             return nil, "Failed signing rock: " .. err
@@ -95,7 +91,7 @@ function upload.command(flags, fname)
    local multipart = require("luarocks.upload.multipart")
 
    res, err = api:method("upload", nil, {
-     rockspec_file = multipart.new_file(fname),
+     rockspec_file = multipart.new_file(args.rockspec),
      rockspec_sig = sigfname and multipart.new_file(sigfname),
    })
    if not res then return nil, err end
diff --git a/src/luarocks/cmd/which.lua b/src/luarocks/cmd/which.lua
index 56db5254..9a363e85 100644
--- a/src/luarocks/cmd/which.lua
+++ b/src/luarocks/cmd/which.lua
@@ -8,20 +8,20 @@ local cfg = require("luarocks.core.cfg")
 local util = require("luarocks.util")
 local fs = require("luarocks.fs")
 
-which_cmd.help_summary = "Tell which file corresponds to a given module name."
-which_cmd.help_arguments = "<modname>"
-which_cmd.help = [[
-Given a module name like "foo.bar", output which file would be loaded to resolve
-that module by luarocks.loader, like "/usr/local/lua/]]..cfg.lua_version..[[/foo/bar.lua".
-]]
-
---- Driver function for "lua" command.
+function which_cmd.add_to_parser(parser)
+   local cmd = parser:command("which", 'Given a module name like "foo.bar", '..
+      "output which file would be loaded to resolve that module by "..
+      'luarocks.loader, like "/usr/local/lua/'..cfg.lua_version..'/foo/bar.lua".',
+      util.see_also())
+      :summary("Tell which file corresponds to a given module name.")
+
+   cmd:argument("modname", "Module name.")
+end
+
+--- Driver function for "which" command.
 -- @return boolean This function terminates the interpreter.
-function which_cmd.command(_, modname)
-   if modname == nil then
-      return nil, "Missing module name. " .. util.see_help("which")
-   end
-   local pathname, rock_name, rock_version = loader.which(modname)
+function which_cmd.command(args)
+   local pathname, rock_name, rock_version = loader.which(args.modname)
 
    if pathname then
       util.printout(pathname)
@@ -29,7 +29,7 @@ function which_cmd.command(_, modname)
       return true
    end
 
-   local modpath = modname:gsub("%.", "/")
+   local modpath = args.modname:gsub("%.", "/")
    for _, v in ipairs({"path", "cpath"}) do
       for p in package[v]:gmatch("([^;]+)") do
          local pathname = p:gsub("%?", modpath)
@@ -41,7 +41,7 @@ function which_cmd.command(_, modname)
       end
    end
 
-   return nil, "Module '" .. modname .. "' not found."
+   return nil, "Module '" .. args.modname .. "' not found."
 end
 
 return which_cmd
diff --git a/src/luarocks/cmd/write_rockspec.lua b/src/luarocks/cmd/write_rockspec.lua
index aad91910..ee825ce4 100644
--- a/src/luarocks/cmd/write_rockspec.lua
+++ b/src/luarocks/cmd/write_rockspec.lua
@@ -11,36 +11,69 @@ local rockspecs = require("luarocks.rockspecs")
 local type_rockspec = require("luarocks.type.rockspec")
 local util = require("luarocks.util")
 
-write_rockspec.help_summary = "Write a template for a rockspec file."
-write_rockspec.help_arguments = "[--output=<file> ...] [<name>] [<version>] [<url>|<path>]"
-write_rockspec.help = [[
+local lua_versions = {
+   "5.1",
+   "5.2",
+   "5.3",
+   "5.4",
+   "5.1,5.2",
+   "5.2,5.3",
+   "5.3,5.4",
+   "5.1,5.2,5.3",
+   "5.2,5.3,5.4",
+   "5.1,5.2,5.3,5.4"
+}
+
+function write_rockspec.cmd_options(parser)
+   return parser:option("--output", "Write the rockspec with the given filename.\n"..
+         "If not given, a file is written in the current directory with a "..
+         "filename based on given name and version.")
+         :argname("<file>"),
+      parser:option("--license", 'A license string, such as "MIT/X11" or "GNU GPL v3".')
+         :argname("<string>"),
+      parser:option("--summary", "A short one-line description summary.")
+         :argname("<txt>"),
+      parser:option("--detailed", "A longer description string.")
+         :argname("<txt>"),
+      parser:option("--homepage", "Project homepage.")
+         :argname("<txt>"),
+      parser:option("--lua-versions", 'Supported Lua versions. Accepted values are: "'..
+         table.concat(lua_versions, '", "')..'".')
+         :argname("<ver>")
+         :choices(lua_versions),
+      parser:option("--rockspec-format", 'Rockspec format version, such as "1.0" or "1.1".')
+         :argname("<ver>"),
+      parser:option("--tag", "Tag to use. Will attempt to extract version number from it."),
+      parser:option("--lib", "A comma-separated list of libraries that C files need to link to.")
+         :argname("<libs>")
+end
+
+function write_rockspec.add_to_parser(parser)
+   local cmd = parser:command("write_rockspec", [[
 This command writes an initial version of a rockspec file,
 based on a name, a version, and a location (an URL or a local path).
 If only two arguments are given, the first one is considered the name and the
 second one is the location.
 If only one argument is given, it must be the location.
-If no arguments are given, current directory is used as location.
+If no arguments are given, current directory is used as the location.
 LuaRocks will attempt to infer name and version if not given,
 using 'dev' as a fallback default version.
 
 Note that the generated file is a _starting point_ for writing a
-rockspec, and is not guaranteed to be complete or correct.
-
---output=<file>          Write the rockspec with the given filename.
-                         If not given, a file is written in the current
-                         directory with a filename based on given name and version.
---license="<string>"     A license string, such as "MIT/X11" or "GNU GPL v3".
---summary="<txt>"        A short one-line description summary.
---detailed="<txt>"       A longer description string.
---homepage=<url>         Project homepage.
---lua-versions=<ver>     Supported Lua versions.  Accepted values are: "5.1", "5.2",
-                         "5.3", "5.4", "5.1,5.2", "5.2,5.3", "5.3,5.4", "5.1,5.2,5.3",
-                         "5.2,5.3,5.4", or "5.1,5.2,5.3,5.4"
---rockspec-format=<ver>  Rockspec format version, such as "1.0" or "1.1".
---tag=<tag>              Tag to use. Will attempt to extract version number from it.
---lib=<lib>[,<lib>]      A comma-separated list of libraries that C files need to
-                         link to.
-]]
+rockspec, and is not guaranteed to be complete or correct. ]], util.see_also())
+      :summary("Write a template for a rockspec file.")
+
+   parser:command("write-rockspec"):hidden(true):action(function(args) args.command = "write_rockspec" end)
+
+   cmd:argument("name", "Name of the rock.")
+      :args("?")
+   cmd:argument("version", "Rock version.")
+      :args("?")
+   cmd:argument("location", "URL or path to the rock sources.")
+      :args("?")
+
+   write_rockspec.cmd_options(cmd)
+end
 
 local function open_file(name)
    return io.open(dir.path(fs.current_dir(), name), "r")
@@ -229,40 +262,42 @@ local function rockspec_cleanup(rockspec)
    end
 end
 
-function write_rockspec.command(flags, name, version, url_or_dir)
+function write_rockspec.command(args)
 
-   name = util.adjust_name_and_namespace(name, flags)
+   local name = util.adjust_name_and_namespace(args.name, args)
+   local version = args.version
+   local location = args.location
 
    if not name then
-      url_or_dir = "."
+      location = "."
    elseif not version then
-      url_or_dir = name
+      location = name
       name = nil
-   elseif not url_or_dir then
-      url_or_dir = version
+   elseif not location then
+      location = version
       version = nil
    end
 
-   if flags["tag"] then
+   if args.tag then
       if not version then
-         version = flags["tag"]:gsub("^v", "")
+         version = args.tag:gsub("^v", "")
       end
    end
 
-   local protocol, pathname = dir.split_url(url_or_dir)
+   local protocol, pathname = dir.split_url(location)
    if protocol == "file" then
       if pathname == "." then
          name = name or dir.base_name(fs.current_dir())
       end
    elseif dir.is_basic_protocol(protocol) then
-      local filename = dir.base_name(url_or_dir)
+      local filename = dir.base_name(location)
       local newname, newversion = filename:match("(.*)-([^-]+)")
       if newname then
          name = name or newname
          version = version or newversion:gsub("%.[a-z]+$", ""):gsub("%.tar$", "")
       end
    else
-      name = name or dir.base_name(url_or_dir):gsub("%.[^.]+$", "")
+      name = name or dir.base_name(location):gsub("%.[^.]+$", "")
    end
 
    if not name then
@@ -270,27 +305,27 @@ function write_rockspec.command(flags, name, version, url_or_dir)
    end
    version = version or "dev"
 
-   local filename = flags["output"] or dir.path(fs.current_dir(), name:lower().."-"..version.."-1.rockspec")
+   local filename = args.output or dir.path(fs.current_dir(), name:lower().."-"..version.."-1.rockspec")
    
-   local url = detect_url(url_or_dir)
-   local homepage = detect_homepage(url, flags["homepage"])
+   local url = detect_url(location)
+   local homepage = detect_homepage(url, args.homepage)
    
    local rockspec, err = rockspecs.from_persisted_table(filename, {
-      rockspec_format = flags["rockspec-format"],
+      rockspec_format = args.rockspec_format,
       package = name,
       version = version.."-1",
       source = {
          url = url,
-         tag = flags["tag"],
+         tag = args.tag,
       },
       description = {
-         summary = flags["summary"] or "*** please specify description summary ***",
-         detailed = flags["detailed"] or "*** please enter a detailed description ***",
+         summary = args.summary or "*** please specify description summary ***",
+         detailed = args.detailed or "*** please enter a detailed description ***",
          homepage = homepage,
-         license = flags["license"] or "*** please specify a license ***",
+         license = args.license or "*** please specify a license ***",
       },
       dependencies = {
-         lua_version_dep[flags["lua-versions"]],
+         lua_version_dep[args.lua_versions],
       },
       build = {},
    })
@@ -301,19 +336,19 @@ function write_rockspec.command(flags, name, version, url_or_dir)
       util.warning("Please specify supported Lua versions with --lua-versions=<ver>. "..util.see_help("write_rockspec"))
    end
    
-   local local_dir = url_or_dir
+   local local_dir = location
 
-   if url_or_dir:match("://") then
-      rockspec.source.file = dir.base_name(url_or_dir)
+   if location:match("://") then
+      rockspec.source.file = dir.base_name(location)
       if not dir.is_basic_protocol(rockspec.source.protocol) then
          if version ~= "dev" then
-            rockspec.source.tag = flags["tag"] or "v" .. version
+            rockspec.source.tag = args.tag or "v" .. version
          end
       end
       rockspec.source.dir = nil
       local ok, base_dir, temp_dir = fetch_url(rockspec)
       if ok then
-         if base_dir ~= dir.base_name(url_or_dir) then
+         if base_dir ~= dir.base_name(location) then
             rockspec.source.dir = base_dir
          end
       end
@@ -329,10 +364,10 @@ function write_rockspec.command(flags, name, version, url_or_dir)
    end
    
    local libs = nil
-   if flags["lib"] then
+   if args.lib then
       libs = {}
       rockspec.external_dependencies = {}
-      for lib in flags["lib"]:gmatch("([^,]+)") do
+      for lib in args.lib:gmatch("([^,]+)") do
          table.insert(libs, lib)
          rockspec.external_dependencies[lib:upper()] = {
             library = lib
@@ -343,13 +378,13 @@ function write_rockspec.command(flags, name, version, url_or_dir)
    local ok, err = fs.change_dir(local_dir)
    if not ok then return nil, "Failed reaching files from project - error entering directory "..local_dir end
 
-   if not (flags["summary"] and flags["detailed"]) then
+   if not (args.summary and args.detailed) then
       local summary, detailed = detect_description()
-      rockspec.description.summary = flags["summary"] or summary
-      rockspec.description.detailed = flags["detailed"] or detailed
+      rockspec.description.summary = args.summary or summary
+      rockspec.description.detailed = args.detailed or detailed
    end
 
-   if not flags["license"] then
+   if not args.license then
       local license, fulltext = check_license()
       if license then
          rockspec.description.license = license
diff --git a/src/luarocks/deps.lua b/src/luarocks/deps.lua
index 9ee21772..cb85764e 100644
--- a/src/luarocks/deps.lua
+++ b/src/luarocks/deps.lua
@@ -170,12 +170,13 @@ function deps.fulfill_dependency(dep, deps_mode, name, version, rocks_provided,
       return nil, "Could not satisfy dependency "..tostring(dep)..": "..search_err
    end
    util.printout("Installing "..url)
-   local install_flags = {
+   local install_args = {
+      rock = url,
       deps_mode = deps_mode,
       namespace = dep.namespace,
       verify = verify,
    }
-   local ok, install_err, errcode = install.command(install_flags, url)
+   local ok, install_err, errcode = install.command(install_args)
    if not ok then
       return nil, "Failed installing dependency: "..url.." - "..install_err, errcode
    end
@@ -569,23 +570,8 @@ function deps.check_lua_libdir(vars)
    return nil, "Failed finding Lua library. You may need to configure LUA_LIBDIR.", "dependency"
 end
 
-local valid_deps_modes = {
-   one = true,
-   order = true,
-   all = true,
-   none = true,
-}
-
-function deps.check_deps_mode_flag(flag)
-   return valid_deps_modes[flag]
-end
-
-function deps.get_deps_mode(flags)
-   if flags["deps-mode"] then
-      return flags["deps-mode"]
-   else
-      return cfg.deps_mode
-   end
+function deps.get_deps_mode(args)
+   return args.deps_mode or cfg.deps_mode
 end
 
 return deps
diff --git a/src/luarocks/fs/lua.lua b/src/luarocks/fs/lua.lua
index 56583676..6028a925 100644
--- a/src/luarocks/fs/lua.lua
+++ b/src/luarocks/fs/lua.lua
@@ -1092,10 +1092,10 @@ end
 
 --- Check if user has write permissions for the command.
 -- Assumes the configuration variables under cfg have been previously set up.
--- @param flags table: the flags table passed to run() drivers.
+-- @param args table: the args table passed to run() drivers.
 -- @return boolean or (boolean, string): true on success, false on failure,
 -- plus an error message.
-function fs_lua.check_command_permissions(flags)
+function fs_lua.check_command_permissions(args)
    local ok = true
    local err = ""
    for _, directory in ipairs { cfg.rocks_dir, cfg.deploy_lua_dir, cfg.deploy_bin_dir, cfg.deploy_lua_dir } do
@@ -1124,7 +1124,7 @@ function fs_lua.check_command_permissions(flags)
    if ok then
       return true
    else
-      if flags["local"] or cfg.local_by_default then
+      if args["local"] or cfg.local_by_default then
          err = err .. " \n-- please check your permissions."
       else
          err = err .. " \n-- you may want to run as a privileged user or use your local tree with --local."
diff --git a/src/luarocks/manif/writer.lua b/src/luarocks/manif/writer.lua
index 23ba2532..d6b70a5f 100644
--- a/src/luarocks/manif/writer.lua
+++ b/src/luarocks/manif/writer.lua
@@ -279,7 +279,7 @@ function writer.make_rock_manifest(name, version)
 end
 
 -- Writes a 'rock_namespace' file in a locally installed rock directory.
--- @param name string: the rock name (may be in user/rock format)
+-- @param name string: the rock name, without a namespace
 -- @param version string: the rock version
 -- @param namespace string?: the namespace
 -- @return true if successful (or unnecessary, if there is no namespace),
@@ -288,8 +288,6 @@ function writer.make_namespace_file(name, version, namespace)
    assert(type(name) == "string" and not name:match("/"))
    assert(type(version) == "string")
    assert(type(namespace) == "string" or not namespace)
-   name = util.adjust_name_and_namespace(name, { namespace = namespace })
-   name, namespace = util.split_namespace(name)
    if not namespace then
       return true
    end
diff --git a/src/luarocks/upload/api.lua b/src/luarocks/upload/api.lua
index 0e71432f..a28b517a 100644
--- a/src/luarocks/upload/api.lua
+++ b/src/luarocks/upload/api.lua
@@ -245,20 +245,20 @@ end
 
 end
 
-function api.new(flags)
+function api.new(args)
    local self = {}
    setmetatable(self, { __index = Api })
    self.config = self:load_config() or {}
-   self.config.server = flags["server"] or self.config.server or cfg.upload.server
+   self.config.server = args.server or self.config.server or cfg.upload.server
    self.config.version = self.config.version or cfg.upload.version
-   self.config.key = flags["temp-key"] or flags["api-key"] or self.config.key
-   self.debug = flags["debug"]
+   self.config.key = args.temp_key or args.api_key or self.config.key
+   self.debug = args.debug
    if not self.config.key then
       return nil, "You need an API key to upload rocks.\n" ..
                   "Navigate to "..self.config.server.."/settings to get a key\n" ..
                   "and then pass it through the --api-key=<key> flag."
    end
-   if flags["api-key"] then
+   if args.api_key then
       self:save_config()
    end
    return self
diff --git a/src/luarocks/util.lua b/src/luarocks/util.lua
index 8b84df4d..d4461c92 100644
--- a/src/luarocks/util.lua
+++ b/src/luarocks/util.lua
@@ -77,162 +77,6 @@ function util.matchquote(s)
    return (s:gsub("[?%-+*%[%].%%()$^]","%%%1"))
 end
 
---- List of supported arguments.
--- Arguments that take no parameters are marked with the boolean true.
--- Arguments that take a parameter are marked with a descriptive string.
--- Arguments that may take an empty string are described in quotes,
--- (as in the value for --detailed="<text>").
--- For all other string values, it means the parameter is mandatory.
-local supported_flags = {
-   ["all"] = true,
-   ["api-key"] = "<key>",
-   ["append"] = true,
-   ["arch"] = "<arch>",
-   ["bin"] = true,
-   ["binary"] = true,
-   ["branch"] = "<branch-name>",
-   ["build-deps"] = true,
-   ["debug"] = true,
-   ["deps"] = true,
-   ["deps-mode"] = "<mode>",
-   ["detailed"] = "\"<text>\"",
-   ["dev"] = true,
-   ["dir"] = "<path>",
-   ["force"] = true,
-   ["force-fast"] = true,
-   ["from"] = "<server>",
-   ["global"] = true,
-   ["help"] = true,
-   ["home"] = true,
-   ["homepage"] = "\"<url>\"",
-   ["index"] = true,
-   ["issues"] = true,
-   ["json"] = true,
-   ["keep"] = true,
-   ["labels"] = true,
-   ["lib"] = "<library>",
-   ["license"] = "\"<text>\"",
-   ["list"] = true,
-   ["local"] = true,
-   ["local-tree"] = true,
-   ["lr-bin"] = true,
-   ["lr-cpath"] = true,
-   ["lr-path"] = true,
-   ["lua-dir"] = "<path>",
-   ["lua-version"] = "<vers>",
-   ["lua-versions"] = "<versions>",
-   ["lua-ver"] = true,
-   ["lua-incdir"] = true,
-   ["lua-libdir"] = true,
-   ["modules"] = true,
-   ["mversion"] = true,
-   ["namespace"] = "<namespace>",
-   ["no-bin"] = true,
-   ["no-doc"] = true,
-   ["no-refresh"] = true,
-   ["nodeps"] = true,
-   ["old-versions"] = true,
-   ["only-deps"] = true,
-   ["only-from"] = "<server>",
-   ["only-server"] = "<server>",
-   ["only-sources"] = "<url>",
-   ["only-sources-from"] = "<url>",
-   ["outdated"] = true,
-   ["output"] = "<file>",
-   ["pack-binary-rock"] = true,
-   ["porcelain"] = true,
-   ["project-tree"] = "<tree>",
-   ["quick"] = true,
-   ["reset"] = true,
-   ["rock-dir"] = true,
-   ["rock-license"] = true,
-   ["rock-namespace"] = true,
-   ["rock-tree"] = true,
-   ["rock-trees"] = true,
-   ["rockspec"] = true,
-   ["rockspec-format"] = "<ver>",
-   ["scope"] = "<system|user|project>",
-   ["server"] = "<server>",
-   ["sign"] = true,
-   ["skip-pack"] = true,
-   ["source"] = true,
-   ["summary"] = "\"<text>\"",
-   ["system-config"] = true,
-   ["tag"] = "<tag>",
-   ["test-type"] = "<type>",
-   ["temp-key"] = "<key>",
-   ["timeout"] = "<seconds>",
-   ["to"] = "<path>",
-   ["tree"] = "<path>",
-   ["unset"] = true,
-   ["user-config"] = true,
-   ["verbose"] = true,
-   ["verify"] = true,
-   ["version"] = true,
-}
-
---- Extract flags from an arguments list.
--- Given string arguments, extract flag arguments into a flags set.
--- For example, given "foo", "--tux=beep", "--bla", "bar", "--baz",
--- it would return the following:
--- {["bla"] = true, ["tux"] = "beep", ["baz"] = true}, "foo", "bar".
-function util.parse_flags(...)
-   local args = {...}
-   local flags = {}
-   local i = 1
-   local out = {}
-   local state = "initial"
-   while i <= #args do
-      local flag = args[i]:match("^%-%-(.*)")
-      if state == "initial" and flag == "" then
-         state = "ignore_flags"
-      elseif state == "initial" and flag then
-         local var,val = flag:match("([a-z_%-]*)=(.*)")
-         if val then
-            local vartype = supported_flags[var]
-            if type(vartype) == "string" then
-               if val == "" and vartype:sub(1,1) ~= '"' then
-                  return { ERROR = "Invalid argument: parameter to flag --"..var.."="..vartype.." cannot be empty." }
-               end
-               flags[var] = val
-            else
-               if vartype then
-                  return { ERROR = "Invalid argument: flag --"..var.." does not take an parameter." }
-               else
-                  return { ERROR = "Invalid argument: unknown flag --"..var.."." }
-               end
-            end
-         else
-            local var = flag
-            local vartype = supported_flags[var]
-            if type(vartype) == "string" then
-               i = i + 1
-               local val = args[i]
-               if not val then
-                  return { ERROR = "Invalid argument: flag --"..var.."="..vartype.." expects a parameter." }
-               end
-               if val:match("^%-%-.*") then
-                  return { ERROR = "Invalid argument: flag --"..var.."="..vartype.." expects a parameter (if you really want to pass "..val.." as an argument to --"..var..", use --"..var.."="..val..")." }
-               else
-                  if val == "" and vartype:sub(1,1) ~= '"' then
-                     return { ERROR = "Invalid argument: parameter to flag --"..var.."="..vartype.." cannot be empty." }
-                  end
-                  flags[var] = val
-               end
-            elseif vartype == true then
-               flags[var] = true
-            else
-               return { ERROR = "Invalid argument: unknown flag --"..var.."." }
-            end
-         end
-      elseif state == "ignore_flags" or (state == "initial" and not flag) then
-         table.insert(out, args[i])
-      end
-      i = i + 1
-   end
-   return flags, unpack(out)
-end
-
 local var_format_pattern = "%$%((%a[%a%d_]+)%)"
 
 -- Check if a set of needed variables are referenced
@@ -371,29 +215,36 @@ function util.this_program(default)
    return prog
 end
 
-function util.deps_mode_help(program)
+function util.deps_mode_option(parser, program)
    local cfg = require("luarocks.core.cfg")
-   return [[
---deps-mode=<mode>  How to handle dependencies. Four modes are supported:
-                    * all - use all trees from the rocks_trees list
-                      for finding dependencies
-                    * one - use only the current tree (possibly set
-                      with --tree)
-                    * order - use trees based on order (use the current
-                      tree and all trees below it on the rocks_trees list)
-                    * none - ignore dependencies altogether.
-                    The default mode may be set with the deps_mode entry
-                    in the configuration file.
-                    The current default is "]]..cfg.deps_mode..[[".
-                    Type ']]..util.this_program(program or "luarocks")..[[' with no arguments to see
-                    your list of rocks trees.
-]]
+
+   parser:option("--deps-mode", "How to handle dependencies. Four modes are supported:\n"..
+      "* all - use all trees from the rocks_trees list for finding dependencies\n"..
+      "* one - use only the current tree (possibly set with --tree)\n"..
+      "* order - use trees based on order (use the current tree and all "..
+      "trees below it on the rocks_trees list)\n"..
+      "* none - ignore dependencies altogether.\n"..
+      "The default mode may be set with the deps_mode entry in the configuration file.\n"..
+      'The current default is "'..cfg.deps_mode..'".\n'..
+      "Type '"..util.this_program(program or "luarocks").."' with no "..
+      "arguments to see your list of rocks trees.")
+      :argname("<mode>")
+      :choices({"all", "one", "order", "none"})
+   parser:flag("--nodeps"):hidden(true)
 end
 
 function util.see_help(command, program)
    return "See '"..util.this_program(program or "luarocks")..' help'..(command and " "..command or "").."'."
 end
 
+function util.see_also(text)
+   local see_also = "See also:\n"
+   if text then
+      see_also = see_also..text.."\n"
+   end
+   return see_also.."   '"..util.this_program("luarocks").." help' for general options and configuration."
+end
+
 function util.announce_install(rockspec)
    local cfg = require("luarocks.core.cfg")
    local path = require("luarocks.path")
@@ -487,13 +338,13 @@ function util.LQ(s)
    return ("%q"):format(s)
 end
 
---- Normalize the --namespace flag and the user/rock syntax for namespaces.
--- If a namespace is given in user/rock syntax, update the --namespace flag;
--- If a namespace is given in --namespace flag, update the user/rock syntax.
+--- Normalize the --namespace option and the user/rock syntax for namespaces.
+-- If a namespace is given in user/rock syntax, update the --namespace option;
+-- If a namespace is given in --namespace option, update the user/rock syntax.
 -- In case of conflicts, the user/rock syntax takes precedence.
-function util.adjust_name_and_namespace(ns_name, flags)
+function util.adjust_name_and_namespace(ns_name, args)
    assert(type(ns_name) == "string" or not ns_name)
-   assert(type(flags) == "table")
+   assert(type(args) == "table")
 
    if not ns_name then
       return
@@ -503,10 +354,10 @@ function util.adjust_name_and_namespace(ns_name, flags)
 
    local name, namespace = util.split_namespace(ns_name)
    if namespace then
-      flags["namespace"] = namespace
+      args.namespace = namespace
    end
-   if flags["namespace"] then
-      name = flags["namespace"] .. "/" .. name
+   if args.namespace then
+      name = args.namespace .. "/" .. name
    end
    return name:lower()
 end