Reorganize luarocks.core requires and type checking tables

* For each `luarocks.core.x` module, make `luarocks.x` module
  load the core module explicitly as `core`, and expose its
  relevant methods explicitly as well (instead of using
  `setmetatable`).
* Move all type checking out of the core, adjusting the manifest
  modules accordingly.
* Create separate modules for the rockspec and manifest
  schemas in the `luarocks.type` namespace.

14 files changed, 426 insertions, 381 deletions

diff --git a/src/luarocks/cmd/new_version.lua b/src/luarocks/cmd/new_version.lua
index b13dbb97..5149f924 100644
--- a/src/luarocks/cmd/new_version.lua
+++ b/src/luarocks/cmd/new_version.lua
@@ -8,7 +8,7 @@ local download = require("luarocks.download")
 local fetch = require("luarocks.fetch")
 local persist = require("luarocks.persist")
 local fs = require("luarocks.fs")
-local type_check = require("luarocks.type_check")
+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>] [<package>|<rockspec>] [<new_version>] [<new_url>]"
@@ -184,7 +184,7 @@ function new_version.command(flags, input, version, url)
    
    local out_filename = out_name.."-"..new_rockver.."-"..new_rev..".rockspec"
    
-   persist.save_from_table(out_filename, out_rs, type_check.rockspec_order)
+   persist.save_from_table(out_filename, out_rs, type_rockspec.order)
    
    util.printout("Wrote "..out_filename)
 
diff --git a/src/luarocks/cmd/write_rockspec.lua b/src/luarocks/cmd/write_rockspec.lua
index 73010f08..06d50c69 100644
--- a/src/luarocks/cmd/write_rockspec.lua
+++ b/src/luarocks/cmd/write_rockspec.lua
@@ -7,7 +7,7 @@ local fetch = require("luarocks.fetch")
 local fs = require("luarocks.fs")
 local path = require("luarocks.path")
 local persist = require("luarocks.persist")
-local type_check = require("luarocks.type_check")
+local type_rockspec = require("luarocks.type.rockspec")
 local util = require("luarocks.util")
 local vers = require("luarocks.vers")
 
@@ -364,7 +364,7 @@ function write_rockspec.command(flags, name, version, url_or_dir)
       
    rockspec_cleanup(rockspec)
    
-   persist.save_from_table(filename, rockspec, type_check.rockspec_order)
+   persist.save_from_table(filename, rockspec, type_rockspec.order)
 
    util.printout()   
    util.printout("Wrote template at "..filename.." -- you should now edit and finish it.")
diff --git a/src/luarocks/core/manif.lua b/src/luarocks/core/manif.lua
index 549cfb4c..cd8d7a06 100644
--- a/src/luarocks/core/manif.lua
+++ b/src/luarocks/core/manif.lua
@@ -3,7 +3,6 @@
 local manif = {}
 
 local persist = require("luarocks.core.persist")
-local type_check = require("luarocks.core.type_check")
 local cfg = require("luarocks.core.cfg")
 local dir = require("luarocks.core.dir")
 local require = nil
@@ -37,24 +36,15 @@ end
 -- @param file string: The local filename of the manifest file.
 -- @param repo_url string: The repository identifier.
 -- @param lua_version string: Lua version in "5.x" format, defaults to installed version.
--- @param quick boolean: If given, skips type checking.
 -- @return table or (nil, string, string): the manifest or nil,
--- error message and error code ("open", "load", "run" or "type").
-function manif.manifest_loader(file, repo_url, lua_version, quick)
+-- error message and error code ("open", "load", "run").
+function manif.manifest_loader(file, repo_url, lua_version)
    local manifest, err, errcode = persist.load_into_table(file)
    if not manifest then
       return nil, "Failed loading manifest for "..repo_url..": "..err, errcode
    end
-   local globals = err
-   if not quick then
-      local ok, err = type_check.type_check_manifest(manifest, globals)
-      if not ok then
-         return nil, "Error checking manifest: "..err, "type"
-      end
-   end
-
    manif.cache_manifest(repo_url, lua_version, manifest)
-   return manifest
+   return manifest, err, errcode
 end
 
 --- Load a local manifest describing a repository.
diff --git a/src/luarocks/core/type_check.lua b/src/luarocks/core/type_check.lua
deleted file mode 100644
index 8b103a58..00000000
--- a/src/luarocks/core/type_check.lua
+++ /dev/null
@@ -1,231 +0,0 @@
-
-local type_check = {}
-
-local cfg = require("luarocks.core.cfg")
-local vers = require("luarocks.core.vers")
-local require = nil
---------------------------------------------------------------------------------
-
-type_check.string_1 = { _type = "string" }
-type_check.number_1 = { _type = "number" }
-type_check.mandatory_string_1 = { _type = "string", _mandatory = true }
-
-local number_1 = type_check.number_1
-local string_1 = type_check.string_1
-local mandatory_string_1 = type_check.mandatory_string_1
-
-local manifest_types = {
-   repository = {
-      _mandatory = true,
-      -- packages
-      _any = {
-         -- versions
-         _any = {
-            -- items
-            _any = {
-               arch = mandatory_string_1,
-               modules = { _any = string_1 },
-               commands = { _any = string_1 },
-               dependencies = { _any = string_1 },
-               -- TODO: to be extended with more metadata.
-            }
-         }
-      }
-   },
-   modules = {
-      _mandatory = true,
-      -- modules
-      _any = {
-         -- providers
-         _any = string_1
-      }
-   },
-   commands = {
-      _mandatory = true,
-      -- modules
-      _any = {
-         -- commands
-         _any = string_1
-      }
-   },
-   dependencies = {
-      -- each module
-      _any = {
-         -- each version
-         _any = {
-            -- each dependency
-            _any = {
-               name = string_1,
-               constraints = {
-                  _any = {
-                     no_upgrade = { _type = "boolean" },
-                     op = string_1,
-                     version = {
-                        string = string_1,
-                        _any = number_1,
-                     }
-                  }
-               }
-            }
-         }
-      }
-   }
-}
-
-local function check_version(version, typetbl, context)
-   local typetbl_version = typetbl._version or "1.0"
-   if vers.compare_versions(typetbl_version, version) then
-      if context == "" then
-         return nil, "Invalid rockspec_format version number in rockspec? Please fix rockspec accordingly."
-      else
-         return nil, context.." is not supported in rockspec format "..version.." (requires version "..typetbl_version.."), please fix the rockspec_format field accordingly."
-      end
-   end
-   return true
-end
-
---- Type check an object.
--- The object is compared against an archetypical value
--- matching the expected type -- the actual values don't matter,
--- only their types. Tables are type checked recursively.
--- @param version string: The version of the item.
--- @param item any: The object being checked.
--- @param typetbl any: The type-checking table for the object.
--- @param context string: A string indicating the "context" where the
--- error occurred (the full table path), for error messages.
--- @return boolean or (nil, string): true if type checking
--- succeeded, or nil and an error message if it failed.
--- @see type_check_table
-local function type_check_item(version, item, typetbl, context)
-   assert(type(version) == "string")
-
-   if typetbl._version and typetbl._version ~= "1.0" then
-      local ok, err = check_version(version, typetbl, context)
-      if not ok then
-         return nil, err
-      end
-   end
-   
-   local item_type = type(item) or "nil"
-   local expected_type = typetbl._type or "table"
-   
-   if expected_type == "number" then
-      if not tonumber(item) then
-         return nil, "Type mismatch on field "..context..": expected a number"
-      end
-   elseif expected_type == "string" then
-      if item_type ~= "string" then
-         return nil, "Type mismatch on field "..context..": expected a string, got "..item_type
-      end
-      if typetbl._pattern then
-         if not item:match("^"..typetbl._pattern.."$") then
-            return nil, "Type mismatch on field "..context..": invalid value "..item.." does not match '"..typetbl._pattern.."'"
-         end
-      end
-   elseif expected_type == "table" then
-      if item_type ~= expected_type then
-         return nil, "Type mismatch on field "..context..": expected a table"
-      else
-         return type_check.type_check_table(version, item, typetbl, context)
-      end
-   elseif item_type ~= expected_type then
-      return nil, "Type mismatch on field "..context..": expected "..expected_type
-   end
-   return true
-end
-
-local function mkfield(context, field)
-   if context == "" then
-      return tostring(field)
-   elseif type(field) == "string" then
-      return context.."."..field
-   else
-      return context.."["..tostring(field).."]"
-   end
-end
-
---- Type check the contents of a table.
--- The table's contents are compared against a reference table,
--- which contains the recognized fields, with archetypical values
--- matching the expected types -- the actual values of items in the
--- reference table don't matter, only their types (ie, for field x
--- in tbl that is correctly typed, type(tbl.x) == type(types.x)).
--- If the reference table contains a field called MORE, then
--- unknown fields in the checked table are accepted.
--- If it contains a field called ANY, then its type will be 
--- used to check any unknown fields. If a field is prefixed
--- with MUST_, it is mandatory; its absence from the table is
--- a type error.
--- Tables are type checked recursively.
--- @param version string: The version of tbl.
--- @param tbl table: The table to be type checked.
--- @param typetbl table: The type-checking table, containing
--- values for recognized fields in the checked table.
--- @param context string: A string indicating the "context" where the
--- error occurred (such as the name of the table the item is a part of),
--- to be used by error messages.
--- @return boolean or (nil, string): true if type checking
--- succeeded, or nil and an error message if it failed.
-function type_check.type_check_table(version, tbl, typetbl, context)
-   assert(type(version) == "string")
-   assert(type(tbl) == "table")
-   assert(type(typetbl) == "table")
-   
-   local ok, err = check_version(version, typetbl, context)
-   if not ok then
-      return nil, err
-   end
-   
-   for k, v in pairs(tbl) do
-      local t = typetbl[k] or typetbl._any
-      if t then 
-         local ok, err = type_check_item(version, v, t, mkfield(context, k))
-         if not ok then return nil, err end
-      elseif typetbl._more then
-         -- Accept unknown field
-      else
-         if not cfg.accept_unknown_fields then
-            return nil, "Unknown field "..k
-         end
-      end
-   end
-   for k, v in pairs(typetbl) do
-      if k:sub(1,1) ~= "_" and v._mandatory then
-         if not tbl[k] then
-            return nil, "Mandatory field "..mkfield(context, k).." is missing."
-         end
-      end
-   end
-   return true
-end
-
-function type_check.check_undeclared_globals(globals, typetbl)
-   local undeclared = {}
-   for glob, _ in pairs(globals) do
-      if not (typetbl[glob] or typetbl["MUST_"..glob]) then
-         table.insert(undeclared, glob)
-      end
-   end
-   if #undeclared == 1 then
-      return nil, "Unknown variable: "..undeclared[1]
-   elseif #undeclared > 1 then
-      return nil, "Unknown variables: "..table.concat(undeclared, ", ")
-   end
-   return true
-end
-
---- Type check a manifest table.
--- Verify the correctness of elements from a 
--- manifest table, reporting on unknown fields and type
--- mismatches.
--- @return boolean or (nil, string): true if type checking
--- succeeded, or nil and an error message if it failed.
-function type_check.type_check_manifest(manifest, globals)
-   assert(type(manifest) == "table")
-   local ok, err = type_check.check_undeclared_globals(globals, manifest_types)
-   if not ok then return nil, err end
-   return type_check.type_check_table("1.0", manifest, manifest_types, "")
-end
-
-return type_check
-
diff --git a/src/luarocks/dir.lua b/src/luarocks/dir.lua
index 71477804..72395e47 100644
--- a/src/luarocks/dir.lua
+++ b/src/luarocks/dir.lua
@@ -1,7 +1,11 @@
 
 --- Generic utilities for handling pathnames.
 local dir = {}
-setmetatable(dir, { __index = require("luarocks.core.dir") })
+
+local core = require("luarocks.core.dir")
+
+dir.path = core.path
+dir.split_url = core.split_url
 
 --- Strip the path off a path+filename.
 -- @param pathname string: A path+name, such as "/a/b/c"
diff --git a/src/luarocks/fetch.lua b/src/luarocks/fetch.lua
index dc467d19..de4a3dee 100644
--- a/src/luarocks/fetch.lua
+++ b/src/luarocks/fetch.lua
@@ -4,7 +4,7 @@ local fetch = {}
 
 local fs = require("luarocks.fs")
 local dir = require("luarocks.dir")
-local type_check = require("luarocks.type_check")
+local type_rockspec = require("luarocks.type.rockspec")
 local path = require("luarocks.path")
 local vers = require("luarocks.vers")
 local persist = require("luarocks.persist")
@@ -199,13 +199,13 @@ function fetch.load_local_rockspec(filename, quick)
    local globals = err
 
    if rockspec.rockspec_format then
-      if vers.compare_versions(rockspec.rockspec_format, type_check.rockspec_format) then
+      if vers.compare_versions(rockspec.rockspec_format, type_rockspec.rockspec_format) then
          return nil, "Rockspec format "..rockspec.rockspec_format.." is not supported, please upgrade LuaRocks."
       end
    end
 
    if not quick then
-      local ok, err = type_check.type_check_rockspec(rockspec, globals)
+      local ok, err = type_rockspec.check(rockspec, globals)
       if not ok then
          return nil, filename..": "..err
       end
diff --git a/src/luarocks/manif.lua b/src/luarocks/manif.lua
index 7f3085db..df9f22ae 100644
--- a/src/luarocks/manif.lua
+++ b/src/luarocks/manif.lua
@@ -3,8 +3,8 @@
 -- They are loaded into manifest tables, which are then used for
 -- performing searches, matching dependencies, etc.
 local manif = {}
-setmetatable(manif, { __index = require("luarocks.core.manif") })
 
+local core = require("luarocks.core.manif")
 local persist = require("luarocks.persist")
 local fetch = require("luarocks.fetch")
 local dir = require("luarocks.dir")
@@ -12,9 +12,32 @@ local fs = require("luarocks.fs")
 local cfg = require("luarocks.core.cfg")
 local path = require("luarocks.path")
 local util = require("luarocks.util")
+local type_manifest = require("luarocks.type.manifest")
+
+manif.cache_manifest = core.cache_manifest
 
 manif.rock_manifest_cache = {}
 
+local function check_manifest(repo_url, manifest, globals)
+   local ok, err = type_manifest.check(manifest, globals)
+   if not ok then
+      core.cache_manifest(repo_url, cfg.lua_version, nil)
+      return nil, "Error checking manifest: "..err, "type"
+   end
+   return manifest
+end
+
+function manif.load_local_manifest(repo_url)
+   local manifest, err, errcode = core.load_local_manifest(repo_url)
+   if not manifest then
+      return nil, err, errcode
+   end
+   if err then
+      return check_manifest(repo_url, manifest, err)
+   end
+   return manifest
+end
+
 function manif.load_rock_manifest(name, version, root)
    assert(type(name) == "string")
    assert(type(version) == "string")
@@ -60,7 +83,7 @@ function manif.load_manifest(repo_url, lua_version)
    assert(type(lua_version) == "string" or not lua_version)
    lua_version = lua_version or cfg.lua_version
 
-   local cached_manifest = manif.get_cached_manifest(repo_url, lua_version)
+   local cached_manifest = core.get_cached_manifest(repo_url, lua_version)
    if cached_manifest then
       return cached_manifest
    end
@@ -94,8 +117,8 @@ function manif.load_manifest(repo_url, lua_version)
    end
    if pathname:match(".*%.zip$") then
       pathname = fs.absolute_name(pathname)
-      local dir = dir.dir_name(pathname)
-      fs.change_dir(dir)
+      local dirname = dir.dir_name(pathname)
+      fs.change_dir(dirname)
       local nozip = pathname:match("(.*)%.zip$")
       fs.delete(nozip)
       local ok = fs.unzip(pathname)
@@ -107,7 +130,11 @@ function manif.load_manifest(repo_url, lua_version)
       end
       pathname = nozip
    end
-   return manif.manifest_loader(pathname, repo_url, lua_version)
+   local manifest, err, errcode = core.manifest_loader(pathname, repo_url, lua_version)
+   if not manifest then
+      return nil, err, errcode
+   end
+   return check_manifest(repo_url, manifest, err)
 end
 
 --- Get type and name of an item (a module or a command) provided by a file.
diff --git a/src/luarocks/path.lua b/src/luarocks/path.lua
index d740331b..8a56233f 100644
--- a/src/luarocks/path.lua
+++ b/src/luarocks/path.lua
@@ -3,12 +3,18 @@
 -- All paths are configured in this module, making it a single
 -- point where the layout of the local installation is defined in LuaRocks.
 local path = {}
-setmetatable(path, { __index = require("luarocks.core.path") })
 
+local core = require("luarocks.core.path")
 local dir = require("luarocks.dir")
 local cfg = require("luarocks.core.cfg")
 local util = require("luarocks.util")
 
+path.rocks_dir = core.rocks_dir
+path.versioned_name = core.versioned_name
+path.path_to_module = core.path_to_module
+path.deploy_lua_dir = core.deploy_lua_dir
+path.deploy_lib_dir = core.deploy_lib_dir
+
 --- Infer rockspec filename from a rock filename.
 -- @param rock_name string: Pathname of a rock file.
 -- @return string: Filename of the rockspec, without path.
diff --git a/src/luarocks/persist.lua b/src/luarocks/persist.lua
index 6d5e917b..1460bd15 100644
--- a/src/luarocks/persist.lua
+++ b/src/luarocks/persist.lua
@@ -4,10 +4,12 @@
 -- Implemented separately to avoid interdependencies,
 -- as it is used in the bootstrapping stage of the cfg module.
 local persist = {}
-setmetatable(persist, { __index = require("luarocks.core.persist") })
 
+local core = require("luarocks.core.persist")
 local util = require("luarocks.util")
 
+persist.load_into_table = core.load_into_table
+
 local write_table
 
 --- Write a value as Lua code.
diff --git a/src/luarocks/type/manifest.lua b/src/luarocks/type/manifest.lua
new file mode 100644
index 00000000..f58ff984
--- /dev/null
+++ b/src/luarocks/type/manifest.lua
@@ -0,0 +1,81 @@
+local type_manifest = {}
+
+local type_check = require("luarocks.type_check")
+
+local number_1 = type_check.number_1
+local string_1 = type_check.string_1
+local mandatory_string_1 = type_check.mandatory_string_1
+
+local manifest_types = {
+   repository = {
+      _mandatory = true,
+      -- packages
+      _any = {
+         -- versions
+         _any = {
+            -- items
+            _any = {
+               arch = mandatory_string_1,
+               modules = { _any = string_1 },
+               commands = { _any = string_1 },
+               dependencies = { _any = string_1 },
+               -- TODO: to be extended with more metadata.
+            }
+         }
+      }
+   },
+   modules = {
+      _mandatory = true,
+      -- modules
+      _any = {
+         -- providers
+         _any = string_1
+      }
+   },
+   commands = {
+      _mandatory = true,
+      -- modules
+      _any = {
+         -- commands
+         _any = string_1
+      }
+   },
+   dependencies = {
+      -- each module
+      _any = {
+         -- each version
+         _any = {
+            -- each dependency
+            _any = {
+               name = string_1,
+               constraints = {
+                  _any = {
+                     no_upgrade = { _type = "boolean" },
+                     op = string_1,
+                     version = {
+                        string = string_1,
+                        _any = number_1,
+                     }
+                  }
+               }
+            }
+         }
+      }
+   }
+}
+
+
+--- Type check a manifest table.
+-- Verify the correctness of elements from a 
+-- manifest table, reporting on unknown fields and type
+-- mismatches.
+-- @return boolean or (nil, string): true if type checking
+-- succeeded, or nil and an error message if it failed.
+function type_manifest.check(manifest, globals)
+   assert(type(manifest) == "table")
+   local ok, err = type_check.check_undeclared_globals(globals, manifest_types)
+   if not ok then return nil, err end
+   return type_check.type_check_table("1.0", manifest, manifest_types, "")
+end
+
+return type_manifest
diff --git a/src/luarocks/type/rockspec.lua b/src/luarocks/type/rockspec.lua
new file mode 100644
index 00000000..5ff48177
--- /dev/null
+++ b/src/luarocks/type/rockspec.lua
@@ -0,0 +1,130 @@
+local type_rockspec = {}
+
+local type_check = require("luarocks.type_check")
+
+type_rockspec.rockspec_format = "3.0"
+
+local string_1 = type_check.string_1
+local mandatory_string_1 = type_check.mandatory_string_1
+
+local string_3 = { _type = "string", _version = "3.0" }
+local list_of_strings_3 = { _any = string_3, _version = "3.0" }
+
+-- Syntax for type-checking tables:
+--
+-- A type-checking table describes typing data for a value.
+-- Any key starting with an underscore has a special meaning:
+-- _type (string) is the Lua type of the value. Default is "table".
+-- _version (string) is the minimum rockspec_version that supports this value. Default is "1.0".
+-- _mandatory (boolean) indicates if the value is a mandatory key in its container table. Default is false.
+-- For "string" types only:
+--    _pattern (string) is the string-matching pattern, valid for string types only. Default is ".*".
+-- For "table" types only:
+--    _any (table) is the type-checking table for unspecified keys, recursively checked.
+--    _more (boolean) indicates that the table accepts unspecified keys and does not type-check them.
+--    Any other string keys that don't start with an underscore represent known keys and are type-checking tables, recursively checked.
+
+local rockspec_types = {
+   rockspec_format = string_1,
+   package = mandatory_string_1,
+   version = { _type = "string", _pattern = "[%w.]+-[%d]+", _mandatory = true },
+   description = {
+      summary = string_1,
+      detailed = string_1,
+      homepage = string_1,
+      license = string_1,
+      maintainer = string_1,
+      labels = list_of_strings_3,
+      issues_url = string_3,
+   },
+   dependencies = {
+      platforms = {}, -- recursively defined below
+      _any = string_1,
+   },
+   supported_platforms = {
+      _any = string_1,
+   },
+   external_dependencies = {
+      platforms = {}, -- recursively defined below
+      _any = {
+         program = string_1,
+         header = string_1,
+         library = string_1,
+      }
+   },
+   source = {
+      _mandatory = true,
+      platforms = {}, -- recursively defined below
+      url = mandatory_string_1,
+      md5 = string_1,
+      file = string_1,
+      dir = string_1,
+      tag = string_1,
+      branch = string_1,
+      module = string_1,
+      cvs_tag = string_1,
+      cvs_module = string_1,
+   },
+   build = {
+      platforms = {}, -- recursively defined below
+      type = string_1,
+      install = {
+         lua = {
+            _more = true
+         },
+         lib = {
+            _more = true
+         },
+         conf = {
+            _more = true
+         },
+         bin = {
+            _more = true
+         }
+      },
+      copy_directories = {
+         _any = string_1,
+      },
+      _more = true,
+      _mandatory = true
+   },
+   hooks = {
+      platforms = {}, -- recursively defined below
+      post_install = string_1,
+   },
+   deploy = {
+      _version = "1.1",
+      wrap_bin_scripts = { _type = "boolean", _version = "1.1" },
+   }
+}
+
+type_rockspec.order = {"rockspec_format", "package", "version", 
+   { "source", { "url", "tag", "branch", "md5" } },
+   { "description", {"summary", "detailed", "homepage", "license" } },
+   "supported_platforms", "dependencies", "external_dependencies",
+   { "build", {"type", "modules", "copy_directories", "platforms"} },
+   "hooks"}
+
+rockspec_types.build.platforms._any = rockspec_types.build
+rockspec_types.dependencies.platforms._any = rockspec_types.dependencies
+rockspec_types.external_dependencies.platforms._any = rockspec_types.external_dependencies
+rockspec_types.source.platforms._any = rockspec_types.source
+rockspec_types.hooks.platforms._any = rockspec_types.hooks
+
+--- Type check a rockspec table.
+-- Verify the correctness of elements from a 
+-- rockspec table, reporting on unknown fields and type
+-- mismatches.
+-- @return boolean or (nil, string): true if type checking
+-- succeeded, or nil and an error message if it failed.
+function type_rockspec.check(rockspec, globals)
+   assert(type(rockspec) == "table")
+   if not rockspec.rockspec_format then
+      rockspec.rockspec_format = "1.0"
+   end
+   local ok, err = type_check.check_undeclared_globals(globals, rockspec_types)
+   if not ok then return nil, err end
+   return type_check.type_check_table(rockspec.rockspec_format, rockspec, rockspec_types, "")
+end
+
+return type_rockspec
diff --git a/src/luarocks/type_check.lua b/src/luarocks/type_check.lua
index 4b7e68d7..250c6258 100644
--- a/src/luarocks/type_check.lua
+++ b/src/luarocks/type_check.lua
@@ -1,132 +1,155 @@
---- Type-checking functions.
--- Functions and definitions for doing a basic lint check on files
--- loaded by LuaRocks.
-local type_check = {}
-setmetatable(type_check, { __index = require("luarocks.core.type_check") })
 
-type_check.rockspec_format = "3.0"
+local type_check = {}
 
-local string_1 = type_check.string_1
-local mandatory_string_1 = type_check.mandatory_string_1
+local cfg = require("luarocks.core.cfg")
+local vers = require("luarocks.core.vers")
+local require = nil
+--------------------------------------------------------------------------------
 
-local string_3 = { _type = "string", _version = "3.0" }
-local list_of_strings_3 = { _any = string_3, _version = "3.0" }
+type_check.string_1 = { _type = "string" }
+type_check.number_1 = { _type = "number" }
+type_check.mandatory_string_1 = { _type = "string", _mandatory = true }
 
--- Syntax for type-checking tables:
---
--- A type-checking table describes typing data for a value.
--- Any key starting with an underscore has a special meaning:
--- _type (string) is the Lua type of the value. Default is "table".
--- _version (string) is the minimum rockspec_version that supports this value. Default is "1.0".
--- _mandatory (boolean) indicates if the value is a mandatory key in its container table. Default is false.
--- For "string" types only:
---    _pattern (string) is the string-matching pattern, valid for string types only. Default is ".*".
--- For "table" types only:
---    _any (table) is the type-checking table for unspecified keys, recursively checked.
---    _more (boolean) indicates that the table accepts unspecified keys and does not type-check them.
---    Any other string keys that don't start with an underscore represent known keys and are type-checking tables, recursively checked.
+local function check_version(version, typetbl, context)
+   local typetbl_version = typetbl._version or "1.0"
+   if vers.compare_versions(typetbl_version, version) then
+      if context == "" then
+         return nil, "Invalid rockspec_format version number in rockspec? Please fix rockspec accordingly."
+      else
+         return nil, context.." is not supported in rockspec format "..version.." (requires version "..typetbl_version.."), please fix the rockspec_format field accordingly."
+      end
+   end
+   return true
+end
 
-local rockspec_types = {
-   rockspec_format = string_1,
-   package = mandatory_string_1,
-   version = { _type = "string", _pattern = "[%w.]+-[%d]+", _mandatory = true },
-   description = {
-      summary = string_1,
-      detailed = string_1,
-      homepage = string_1,
-      license = string_1,
-      maintainer = string_1,
-      labels = list_of_strings_3,
-      issues_url = string_3,
-   },
-   dependencies = {
-      platforms = {}, -- recursively defined below
-      _any = string_1,
-   },
-   supported_platforms = {
-      _any = string_1,
-   },
-   external_dependencies = {
-      platforms = {}, -- recursively defined below
-      _any = {
-         program = string_1,
-         header = string_1,
-         library = string_1,
-      }
-   },
-   source = {
-      _mandatory = true,
-      platforms = {}, -- recursively defined below
-      url = mandatory_string_1,
-      md5 = string_1,
-      file = string_1,
-      dir = string_1,
-      tag = string_1,
-      branch = string_1,
-      module = string_1,
-      cvs_tag = string_1,
-      cvs_module = string_1,
-   },
-   build = {
-      platforms = {}, -- recursively defined below
-      type = string_1,
-      install = {
-         lua = {
-            _more = true
-         },
-         lib = {
-            _more = true
-         },
-         conf = {
-            _more = true
-         },
-         bin = {
-            _more = true
-         }
-      },
-      copy_directories = {
-         _any = string_1,
-      },
-      _more = true,
-      _mandatory = true
-   },
-   hooks = {
-      platforms = {}, -- recursively defined below
-      post_install = string_1,
-   },
-   deploy = {
-      _version = "1.1",
-      wrap_bin_scripts = { _type = "boolean", _version = "1.1" },
-   }
-}
+--- Type check an object.
+-- The object is compared against an archetypical value
+-- matching the expected type -- the actual values don't matter,
+-- only their types. Tables are type checked recursively.
+-- @param version string: The version of the item.
+-- @param item any: The object being checked.
+-- @param typetbl any: The type-checking table for the object.
+-- @param context string: A string indicating the "context" where the
+-- error occurred (the full table path), for error messages.
+-- @return boolean or (nil, string): true if type checking
+-- succeeded, or nil and an error message if it failed.
+-- @see type_check_table
+local function type_check_item(version, item, typetbl, context)
+   assert(type(version) == "string")
 
-type_check.rockspec_order = {"rockspec_format", "package", "version", 
-   { "source", { "url", "tag", "branch", "md5" } },
-   { "description", {"summary", "detailed", "homepage", "license" } },
-   "supported_platforms", "dependencies", "external_dependencies",
-   { "build", {"type", "modules", "copy_directories", "platforms"} },
-   "hooks"}
+   if typetbl._version and typetbl._version ~= "1.0" then
+      local ok, err = check_version(version, typetbl, context)
+      if not ok then
+         return nil, err
+      end
+   end
+   
+   local item_type = type(item) or "nil"
+   local expected_type = typetbl._type or "table"
+   
+   if expected_type == "number" then
+      if not tonumber(item) then
+         return nil, "Type mismatch on field "..context..": expected a number"
+      end
+   elseif expected_type == "string" then
+      if item_type ~= "string" then
+         return nil, "Type mismatch on field "..context..": expected a string, got "..item_type
+      end
+      if typetbl._pattern then
+         if not item:match("^"..typetbl._pattern.."$") then
+            return nil, "Type mismatch on field "..context..": invalid value "..item.." does not match '"..typetbl._pattern.."'"
+         end
+      end
+   elseif expected_type == "table" then
+      if item_type ~= expected_type then
+         return nil, "Type mismatch on field "..context..": expected a table"
+      else
+         return type_check.type_check_table(version, item, typetbl, context)
+      end
+   elseif item_type ~= expected_type then
+      return nil, "Type mismatch on field "..context..": expected "..expected_type
+   end
+   return true
+end
 
-rockspec_types.build.platforms._any = rockspec_types.build
-rockspec_types.dependencies.platforms._any = rockspec_types.dependencies
-rockspec_types.external_dependencies.platforms._any = rockspec_types.external_dependencies
-rockspec_types.source.platforms._any = rockspec_types.source
-rockspec_types.hooks.platforms._any = rockspec_types.hooks
+local function mkfield(context, field)
+   if context == "" then
+      return tostring(field)
+   elseif type(field) == "string" then
+      return context.."."..field
+   else
+      return context.."["..tostring(field).."]"
+   end
+end
 
---- Type check a rockspec table.
--- Verify the correctness of elements from a 
--- rockspec table, reporting on unknown fields and type
--- mismatches.
+--- Type check the contents of a table.
+-- The table's contents are compared against a reference table,
+-- which contains the recognized fields, with archetypical values
+-- matching the expected types -- the actual values of items in the
+-- reference table don't matter, only their types (ie, for field x
+-- in tbl that is correctly typed, type(tbl.x) == type(types.x)).
+-- If the reference table contains a field called MORE, then
+-- unknown fields in the checked table are accepted.
+-- If it contains a field called ANY, then its type will be 
+-- used to check any unknown fields. If a field is prefixed
+-- with MUST_, it is mandatory; its absence from the table is
+-- a type error.
+-- Tables are type checked recursively.
+-- @param version string: The version of tbl.
+-- @param tbl table: The table to be type checked.
+-- @param typetbl table: The type-checking table, containing
+-- values for recognized fields in the checked table.
+-- @param context string: A string indicating the "context" where the
+-- error occurred (such as the name of the table the item is a part of),
+-- to be used by error messages.
 -- @return boolean or (nil, string): true if type checking
 -- succeeded, or nil and an error message if it failed.
-function type_check.type_check_rockspec(rockspec, globals)
-   assert(type(rockspec) == "table")
-   if not rockspec.rockspec_format then
-      rockspec.rockspec_format = "1.0"
+function type_check.type_check_table(version, tbl, typetbl, context)
+   assert(type(version) == "string")
+   assert(type(tbl) == "table")
+   assert(type(typetbl) == "table")
+   
+   local ok, err = check_version(version, typetbl, context)
+   if not ok then
+      return nil, err
+   end
+   
+   for k, v in pairs(tbl) do
+      local t = typetbl[k] or typetbl._any
+      if t then 
+         local ok, err = type_check_item(version, v, t, mkfield(context, k))
+         if not ok then return nil, err end
+      elseif typetbl._more then
+         -- Accept unknown field
+      else
+         if not cfg.accept_unknown_fields then
+            return nil, "Unknown field "..k
+         end
+      end
+   end
+   for k, v in pairs(typetbl) do
+      if k:sub(1,1) ~= "_" and v._mandatory then
+         if not tbl[k] then
+            return nil, "Mandatory field "..mkfield(context, k).." is missing."
+         end
+      end
+   end
+   return true
+end
+
+function type_check.check_undeclared_globals(globals, typetbl)
+   local undeclared = {}
+   for glob, _ in pairs(globals) do
+      if not (typetbl[glob] or typetbl["MUST_"..glob]) then
+         table.insert(undeclared, glob)
+      end
+   end
+   if #undeclared == 1 then
+      return nil, "Unknown variable: "..undeclared[1]
+   elseif #undeclared > 1 then
+      return nil, "Unknown variables: "..table.concat(undeclared, ", ")
    end
-   local ok, err = type_check.check_undeclared_globals(globals, rockspec_types)
-   if not ok then return nil, err end
-   return type_check.type_check_table(rockspec.rockspec_format, rockspec, rockspec_types, "")
+   return true
 end
 
 return type_check
diff --git a/src/luarocks/util.lua b/src/luarocks/util.lua
index 59173449..0af23df6 100644
--- a/src/luarocks/util.lua
+++ b/src/luarocks/util.lua
@@ -5,7 +5,15 @@
 -- as this is used in the bootstrapping stage of luarocks.core.cfg.
 
 local util = {}
-setmetatable(util, { __index = require("luarocks.core.util") })
+
+local core = require("luarocks.core.util")
+
+util.popen_read = core.popen_read
+util.cleanup_path = core.cleanup_path
+util.split_string = core.split_string
+util.keys = core.keys
+util.printerr = core.printerr
+util.sortedpairs = core.sortedpairs
 
 local unpack = unpack or table.unpack
 
@@ -223,7 +231,7 @@ function util.platform_overrides(tbl)
       for _, platform in ipairs(cfg.platforms) do
          local platform_tbl = tbl.platforms[platform]
          if platform_tbl then
-            util.deep_merge(tbl, platform_tbl)
+            core.deep_merge(tbl, platform_tbl)
          end
       end
    end
@@ -243,7 +251,7 @@ local var_format_pattern = "%$%((%a[%a%d_]+)%)"
 -- needed variables.
 -- @param msg string: the warning message to display.
 function util.warn_if_not_used(var_defs, needed_set, msg)
-   needed_set = util.make_shallow_copy(needed_set)
+   needed_set = core.make_shallow_copy(needed_set)
    for _, val in pairs(var_defs) do
       for used in val:gmatch(var_format_pattern) do
          needed_set[used] = nil
diff --git a/src/luarocks/vers.lua b/src/luarocks/vers.lua
index d37690a8..c1dfbd39 100644
--- a/src/luarocks/vers.lua
+++ b/src/luarocks/vers.lua
@@ -10,7 +10,12 @@
 -- "common sense" heuristics. The precise specification of the
 -- comparison criteria is the source code of this module.
 local vers = {}
-setmetatable(vers, { __index = require("luarocks.core.vers") })
+
+local core = require("luarocks.core.vers")
+
+vers.parse_version = core.parse_version
+vers.compare_versions = core.compare_versions
+vers.match_constraints = core.match_constraints
 
 --- Check if rockspec format version satisfies version requirement.
 -- @param rockspec table: The rockspec table.