2 files changed, 317 insertions, 242 deletions

diff --git a/compat53/init.lua b/compat53/init.lua
index 96b6c67..a7f0c80 100644
--- a/compat53/init.lua
+++ b/compat53/init.lua
@@ -1,306 +1,373 @@
-local _G, _VERSION, type, pairs, require =
-      _G, _VERSION, type, pairs, require
-
-local M = require("compat53.module")
 local lua_version = _VERSION:sub(-3)
 
 
--- apply other global effects
-if lua_version == "5.1" then
+if lua_version < "5.3" then
+
+   local _G, pairs, require, select, type =
+         _G, pairs, require, select, type
+   local debug, io = debug, io
+   local unpack = lua_version == "5.1" and unpack or table.unpack
 
-   -- cache globals
-   local error, pcall, rawset, select, setmetatable, tostring, unpack, xpcall =
-         error, pcall, rawset, select, setmetatable, tostring, unpack, xpcall
-   local coroutine, debug, io, package, string =
-         coroutine, debug, io, package, string
-   local coroutine_create = coroutine.create
-   local coroutine_resume = coroutine.resume
-   local coroutine_running = coroutine.running
-   local coroutine_status = coroutine.status
-   local coroutine_yield = coroutine.yield
-   local io_type, io_stdout = io.type, io.stdout
+   local M = require("compat53.module")
 
    -- select the most powerful getmetatable function available
    local gmt = type(debug) == "table" and debug.getmetatable or
                getmetatable or function() return false end
+   -- metatable for file objects from Lua's standard io library
+   local file_meta = gmt(io.stdout)
 
-   -- detect LuaJIT (including LUAJIT_ENABLE_LUA52COMPAT compilation flag)
-   local is_luajit = (string.dump(function() end) or ""):sub(1, 3) == "\027LJ"
-   local is_luajit52 = is_luajit and
-     #setmetatable({}, { __len = function() return 1 end }) == 1
 
+   -- make '*' optional for file:read and file:lines
+   if type(file_meta) == "table" and type(file_meta.__index) == "table" then
 
-   -- make package.searchers available as an alias for package.loaders
-   local p_index = { searchers = package.loaders }
-   setmetatable(package, {
-      __index = p_index,
-      __newindex = function(p, k, v)
-         if k == "searchers" then
-            rawset(p, "loaders", v)
-            p_index.searchers = v
+      local function addasterisk(fmt)
+         if type(fmt) == "string" and fmt:sub(1, 1) ~= "*" then
+            return "*"..fmt
          else
-            rawset(p, k, v)
+            return fmt
          end
       end
-   })
-
 
-   if not is_luajit then
-      local function helper(_, var_1, ...)
-         if var_1 == nil then
-            if (...) ~= nil then
-               error((...), 2)
+      local file_lines = file_meta.__index.lines
+      file_meta.__index.lines = function(self, ...)
+         local n = select('#', ...)
+         for i = 1, n do
+            local a = select(i, ...)
+            local b = addasterisk(a)
+            -- as an optimization we only allocate a table for the
+            -- modified format arguments when we have a '*' somewhere
+            if a ~= b then
+               local args = { ... }
+               args[i] = b
+               for j = i+1, n do
+                  args[j] = addasterisk(args[j])
+               end
+               return file_lines(self, unpack(args, 1, n))
             end
          end
-         return var_1, ...
+         return file_lines(self, ...)
       end
 
-      local function lines_iterator(st)
-         return helper(st, st.f:read(unpack(st, 1, st.n)))
+      local file_read = file_meta.__index.read
+      file_meta.__index.read = function(self, ...)
+         local n = select('#', ...)
+         for i = 1, n do
+            local a = select(i, ...)
+            local b = addasterisk(a)
+            -- as an optimization we only allocate a table for the
+            -- modified format arguments when we have a '*' somewhere
+            if a ~= b then
+               local args = { ... }
+               args[i] = b
+               for j = i+1, n do
+                  args[j] = addasterisk(args[j])
+               end
+               return file_read(self, unpack(args, 1, n))
+            end
+         end
+         return file_read(self, ...)
       end
 
-      local valid_format = { ["*l"] = true, ["*n"] = true, ["*a"] = true }
+   end -- got a valid metatable for file objects
 
-      local file_meta = gmt(io_stdout)
-      if type(file_meta) == "table" and type(file_meta.__index) == "table" then
-         local file_write = file_meta.__index.write
-         file_meta.__index.write = function(self, ...)
-            local res, msg, errno = file_write(self, ...)
-            if res then
-               return self
+
+   -- changes for Lua 5.1 only
+   if lua_version == "5.1" then
+
+      -- cache globals
+      local error, pcall, rawset, setmetatable, tostring, xpcall =
+            error, pcall, rawset, setmetatable, tostring, xpcall
+      local coroutine, package, string = coroutine, package, string
+      local coroutine_resume = coroutine.resume
+      local coroutine_running = coroutine.running
+      local coroutine_status = coroutine.status
+      local coroutine_yield = coroutine.yield
+      local io_type = io.type
+
+
+      -- detect LuaJIT (including LUAJIT_ENABLE_LUA52COMPAT compilation flag)
+      local is_luajit = (string.dump(function() end) or ""):sub(1, 3) == "\027LJ"
+      local is_luajit52 = is_luajit and
+        #setmetatable({}, { __len = function() return 1 end }) == 1
+
+
+      -- make package.searchers available as an alias for package.loaders
+      local p_index = { searchers = package.loaders }
+      setmetatable(package, {
+         __index = p_index,
+         __newindex = function(p, k, v)
+            if k == "searchers" then
+               rawset(p, "loaders", v)
+               p_index.searchers = v
             else
-               return nil, msg, errno
+               rawset(p, k, v)
             end
          end
+      })
 
-         file_meta.__index.lines = function(self, ...)
-            if io_type(self) == "closed file" then
-               error("attempt to use a closed file", 2)
-            end
-            local st = { f=self, n=select('#', ...), ... }
-            for i = 1, st.n do
-               if type(st[i]) ~= "number" and not valid_format[st[i]] then
-                  error("bad argument #"..(i+1).." to 'for iterator' (invalid format)", 2)
-               end
-            end
-            return lines_iterator, st
-         end
-      end
-   end -- not luajit
-
-
-   -- the (x)pcall implementations start a new coroutine internally
-   -- to allow yielding even in Lua 5.1. to allow for accurate
-   -- stack traces we keep track of the nested coroutine activations
-   -- in the weak tables below:
-   local weak_meta = { __mode = "kv" }
-   -- maps the internal pcall coroutines to the user coroutine that
-   -- *should* be running if pcall didn't use coroutines internally
-   local pcall_mainOf = setmetatable({}, weak_meta)
-   -- table that maps each running coroutine started by pcall to
-   -- the coroutine that resumed it (user coroutine *or* pcall
-   -- coroutine!)
-   local pcall_previous = setmetatable({}, weak_meta)
-   -- reverse of `pcall_mainOf`. maps a user coroutine to the
-   -- currently active pcall coroutine started within it
-   local pcall_callOf = setmetatable({}, weak_meta)
-   -- similar to `pcall_mainOf` but is used only while executing
-   -- the error handler of xpcall (thus no nesting is necessary!)
-   local xpcall_running = setmetatable({}, weak_meta)
-
-   -- handle debug functions
-   if type(debug) == "table" then
-      local debug_getinfo = debug.getinfo
-      local debug_traceback = debug.traceback
 
-      if not is_luajit then
-         local function calculate_trace_level(co, level)
-            if level ~= nil then
-               for out = 1, 1/0 do
-                  local info = (co==nil) and debug_getinfo(out, "") or debug_getinfo(co, out, "")
-                  if info == nil then
-                     local max = out-1
-                     if level <= max then
-                        return level
-                     end
-                     return nil, level-max
+      if type(file_meta) == "table" and type(file_meta.__index) == "table" then
+         if not is_luajit then
+            local function helper(_, var_1, ...)
+               if var_1 == nil then
+                  if (...) ~= nil then
+                     error((...), 2)
                   end
                end
+               return var_1, ...
             end
-            return 1
-         end
 
-         local stack_pattern = "\nstack traceback:"
-         local stack_replace = ""
-         function debug.traceback(co, msg, level)
-            local lvl
-            local nilmsg
-            if type(co) ~= "thread" then
-               co, msg, level = coroutine_running(), co, msg
+            local function lines_iterator(st)
+               return helper(st, st.f:read(unpack(st, 1, st.n)))
             end
-            if msg == nil then
-               msg = ""
-               nilmsg = true
-            elseif type(msg) ~= "string" then
-               return msg
+
+            local file_write = file_meta.__index.write
+            file_meta.__index.write = function(self, ...)
+               local res, msg, errno = file_write(self, ...)
+               if res then
+                  return self
+               else
+                  return nil, msg, errno
+               end
             end
-            if co == nil then
-               msg = debug_traceback(msg, level or 1)
-            else
-               local xpco = xpcall_running[co]
-               if xpco ~= nil then
-                  lvl, level = calculate_trace_level(xpco, level)
-                  if lvl then
-                     msg = debug_traceback(xpco, msg, lvl)
-                  else
-                     msg = msg..stack_pattern
+
+            file_meta.__index.lines = function(self, ...)
+               if io_type(self) == "closed file" then
+                  error("attempt to use a closed file", 2)
+               end
+               local st = { f=self, n=select('#', ...), ... }
+               for i = 1, st.n do
+                  local t = type(st[i])
+                  if t == "string" then
+                     local fmt = st[i]:match("^*?([aln])")
+                     if not fmt then
+                        error("bad argument #"..(i+1).." to 'for iterator' (invalid format)", 2)
+                     end
+                     st[i] = "*"..fmt
+                  elseif t ~= "number" then
+                     error("bad argument #"..(i+1).." to 'for iterator' (invalid format)", 2)
                   end
-                  lvl, level = calculate_trace_level(co, level)
-                  if lvl then
-                     local trace = debug_traceback(co, "", lvl)
-                     msg = msg..trace:gsub(stack_pattern, stack_replace)
+               end
+               return lines_iterator, st
+            end
+         end -- not luajit
+      end -- file_meta valid
+
+
+      -- the (x)pcall implementations start a new coroutine internally
+      -- to allow yielding even in Lua 5.1. to allow for accurate
+      -- stack traces we keep track of the nested coroutine activations
+      -- in the weak tables below:
+      local weak_meta = { __mode = "kv" }
+      -- maps the internal pcall coroutines to the user coroutine that
+      -- *should* be running if pcall didn't use coroutines internally
+      local pcall_mainOf = setmetatable({}, weak_meta)
+      -- table that maps each running coroutine started by pcall to
+      -- the coroutine that resumed it (user coroutine *or* pcall
+      -- coroutine!)
+      local pcall_previous = setmetatable({}, weak_meta)
+      -- reverse of `pcall_mainOf`. maps a user coroutine to the
+      -- currently active pcall coroutine started within it
+      local pcall_callOf = setmetatable({}, weak_meta)
+      -- similar to `pcall_mainOf` but is used only while executing
+      -- the error handler of xpcall (thus no nesting is necessary!)
+      local xpcall_running = setmetatable({}, weak_meta)
+
+      -- handle debug functions
+      if type(debug) == "table" then
+         local debug_getinfo = debug.getinfo
+         local debug_traceback = debug.traceback
+
+         if not is_luajit then
+            local function calculate_trace_level(co, level)
+               if level ~= nil then
+                  for out = 1, 1/0 do
+                     local info = (co==nil) and debug_getinfo(out, "") or debug_getinfo(co, out, "")
+                     if info == nil then
+                        local max = out-1
+                        if level <= max then
+                           return level
+                        end
+                        return nil, level-max
+                     end
                   end
+               end
+               return 1
+            end
+
+            local stack_pattern = "\nstack traceback:"
+            local stack_replace = ""
+            function debug.traceback(co, msg, level)
+               local lvl
+               local nilmsg
+               if type(co) ~= "thread" then
+                  co, msg, level = coroutine_running(), co, msg
+               end
+               if msg == nil then
+                  msg = ""
+                  nilmsg = true
+               elseif type(msg) ~= "string" then
+                  return msg
+               end
+               if co == nil then
+                  msg = debug_traceback(msg, level or 1)
                else
-                  co = pcall_callOf[co] or co
-                  lvl, level = calculate_trace_level(co, level)
-                  if lvl then
-                     msg = debug_traceback(co, msg, lvl)
+                  local xpco = xpcall_running[co]
+                  if xpco ~= nil then
+                     lvl, level = calculate_trace_level(xpco, level)
+                     if lvl then
+                        msg = debug_traceback(xpco, msg, lvl)
+                     else
+                        msg = msg..stack_pattern
+                     end
+                     lvl, level = calculate_trace_level(co, level)
+                     if lvl then
+                        local trace = debug_traceback(co, "", lvl)
+                        msg = msg..trace:gsub(stack_pattern, stack_replace)
+                     end
                   else
-                     msg = msg..stack_pattern
-                  end
-               end
-               co = pcall_previous[co]
-               while co ~= nil do
-                  lvl, level = calculate_trace_level(co, level)
-                  if lvl then
-                     local trace = debug_traceback(co, "", lvl)
-                     msg = msg..trace:gsub(stack_pattern, stack_replace)
+                     co = pcall_callOf[co] or co
+                     lvl, level = calculate_trace_level(co, level)
+                     if lvl then
+                        msg = debug_traceback(co, msg, lvl)
+                     else
+                        msg = msg..stack_pattern
+                     end
                   end
                   co = pcall_previous[co]
+                  while co ~= nil do
+                     lvl, level = calculate_trace_level(co, level)
+                     if lvl then
+                        local trace = debug_traceback(co, "", lvl)
+                        msg = msg..trace:gsub(stack_pattern, stack_replace)
+                     end
+                     co = pcall_previous[co]
+                  end
                end
+               if nilmsg then
+                  msg = msg:gsub("^\n", "")
+               end
+               msg = msg:gsub("\n\t%(tail call%): %?", "\000")
+               msg = msg:gsub("\n\t%.%.%.\n", "\001\n")
+               msg = msg:gsub("\n\t%.%.%.$", "\001")
+               msg = msg:gsub("(%z+)\001(%z+)", function(some, other)
+                  return "\n\t(..."..#some+#other.."+ tail call(s)...)"
+               end)
+               msg = msg:gsub("\001(%z+)", function(zeros)
+                  return "\n\t(..."..#zeros.."+ tail call(s)...)"
+               end)
+               msg = msg:gsub("(%z+)\001", function(zeros)
+                  return "\n\t(..."..#zeros.."+ tail call(s)...)"
+               end)
+               msg = msg:gsub("%z+", function(zeros)
+                  return "\n\t(..."..#zeros.." tail call(s)...)"
+               end)
+               msg = msg:gsub("\001", function()
+                  return "\n\t..."
+               end)
+               return msg
             end
-            if nilmsg then
-               msg = msg:gsub("^\n", "")
-            end
-            msg = msg:gsub("\n\t%(tail call%): %?", "\000")
-            msg = msg:gsub("\n\t%.%.%.\n", "\001\n")
-            msg = msg:gsub("\n\t%.%.%.$", "\001")
-            msg = msg:gsub("(%z+)\001(%z+)", function(some, other)
-               return "\n\t(..."..#some+#other.."+ tail call(s)...)"
-            end)
-            msg = msg:gsub("\001(%z+)", function(zeros)
-               return "\n\t(..."..#zeros.."+ tail call(s)...)"
-            end)
-            msg = msg:gsub("(%z+)\001", function(zeros)
-               return "\n\t(..."..#zeros.."+ tail call(s)...)"
-            end)
-            msg = msg:gsub("%z+", function(zeros)
-               return "\n\t(..."..#zeros.." tail call(s)...)"
-            end)
-            msg = msg:gsub("\001", function()
-               return "\n\t..."
-            end)
-            return msg
-         end
-      end -- is not luajit
-   end -- debug table available
+         end -- is not luajit
+      end -- debug table available
 
 
-   if not is_luajit52 then
-      local coroutine_running52 = M.coroutine.running
-      function M.coroutine.running()
-         local co, ismain = coroutine_running52()
-         if ismain then
-            return co, true
-         else
-            return pcall_mainOf[co] or co, false
+      if not is_luajit52 then
+         local coroutine_running52 = M.coroutine.running
+         function M.coroutine.running()
+            local co, ismain = coroutine_running52()
+            if ismain then
+               return co, true
+            else
+               return pcall_mainOf[co] or co, false
+            end
          end
       end
-   end
 
-   if not is_luajit then
-      local function pcall_results(current, call, success, ...)
-         if coroutine_status(call) == "suspended" then
-            return pcall_results(current, call, coroutine_resume(call, coroutine_yield(...)))
-         end
-         if pcall_previous then
-            pcall_previous[call] = nil
-            local main = pcall_mainOf[call]
-            if main == current then current = nil end
-            pcall_callOf[main] = current
+      if not is_luajit then
+         local function pcall_results(current, call, success, ...)
+            if coroutine_status(call) == "suspended" then
+               return pcall_results(current, call, coroutine_resume(call, coroutine_yield(...)))
+            end
+            if pcall_previous then
+               pcall_previous[call] = nil
+               local main = pcall_mainOf[call]
+               if main == current then current = nil end
+               pcall_callOf[main] = current
+            end
+            pcall_mainOf[call] = nil
+            return success, ...
          end
-         pcall_mainOf[call] = nil
-         return success, ...
-      end
 
-      local function pcall_exec(current, call, ...)
-         local main = pcall_mainOf[current] or current
-         pcall_mainOf[call] = main
-         if pcall_previous then
-            pcall_previous[call] = current
-            pcall_callOf[main] = call
+         local function pcall_exec(current, call, ...)
+            local main = pcall_mainOf[current] or current
+            pcall_mainOf[call] = main
+            if pcall_previous then
+               pcall_previous[call] = current
+               pcall_callOf[main] = call
+            end
+            return pcall_results(current, call, coroutine_resume(call, ...))
          end
-         return pcall_results(current, call, coroutine_resume(call, ...))
-      end
 
-      local coroutine_create52 = M.coroutine.create
+         local coroutine_create52 = M.coroutine.create
 
-      local function pcall_coroutine(func)
-         if type(func) ~= "function" then
-            local callable = func
-            func = function (...) return callable(...) end
+         local function pcall_coroutine(func)
+            if type(func) ~= "function" then
+               local callable = func
+               func = function (...) return callable(...) end
+            end
+            return coroutine_create52(func)
          end
-         return coroutine_create52(func)
-      end
 
-      function M.pcall(func, ...)
-         local current = coroutine_running()
-         if not current then return pcall(func, ...) end
-         return pcall_exec(current, pcall_coroutine(func), ...)
-      end
+         function M.pcall(func, ...)
+            local current = coroutine_running()
+            if not current then return pcall(func, ...) end
+            return pcall_exec(current, pcall_coroutine(func), ...)
+         end
 
-      local function xpcall_catch(current, call, msgh, success, ...)
-         if not success then
-            xpcall_running[current] = call
-            local ok, result = pcall(msgh, ...)
-            xpcall_running[current] = nil
-            if not ok then
-               return false, "error in error handling ("..tostring(result)..")"
+         local function xpcall_catch(current, call, msgh, success, ...)
+            if not success then
+               xpcall_running[current] = call
+               local ok, result = pcall(msgh, ...)
+               xpcall_running[current] = nil
+               if not ok then
+                  return false, "error in error handling ("..tostring(result)..")"
+               end
+               return false, result
             end
-            return false, result
+            return true, ...
          end
-         return true, ...
-      end
 
-      function M.xpcall(f, msgh, ...)
-         local current = coroutine_running()
-         if not current then
-            local args, n = { ... }, select('#', ...)
-            return xpcall(function() return f(unpack(args, 1, n)) end, msgh)
+         function M.xpcall(f, msgh, ...)
+            local current = coroutine_running()
+            if not current then
+               local args, n = { ... }, select('#', ...)
+               return xpcall(function() return f(unpack(args, 1, n)) end, msgh)
+            end
+            local call = pcall_coroutine(f)
+            return xpcall_catch(current, call, msgh, pcall_exec(current, call, ...))
          end
-         local call = pcall_coroutine(f)
-         return xpcall_catch(current, call, msgh, pcall_exec(current, call, ...))
-      end
-   end -- not luajit
+      end -- not luajit
 
-end -- lua == 5.1
+   end -- lua 5.1
 
 
--- handle exporting to global scope
-local function extend_table(from, to)
-   if from ~= to then
-      for k,v in pairs(from) do
-         if type(v) == "table" and
-            type(to[k]) == "table" and
-            v ~= to[k] then
-            extend_table(v, to[k])
-         else
-            to[k] = v
+   -- handle exporting to global scope
+   local function extend_table(from, to)
+      if from ~= to then
+         for k,v in pairs(from) do
+            if type(v) == "table" and
+               type(to[k]) == "table" and
+               v ~= to[k] then
+               extend_table(v, to[k])
+            else
+               to[k] = v
+            end
          end
       end
    end
-end
 
-extend_table(M, _G)
+   extend_table(M, _G)
+
+end -- lua < 5.3
 
 -- vi: set expandtab softtabstop=3 shiftwidth=3 :
diff --git a/tests/test.lua b/tests/test.lua
index c634ebe..0c77240 100755
--- a/tests/test.lua
+++ b/tests/test.lua
@@ -541,10 +541,18 @@ ___''
 do
    writefile("data.txt", "123 18.8 hello world\ni'm here\n")
    io.input("data.txt")
-   print(io.read("*n", "*number", "*l", "*a"))
+   print("io.read()", io.read("*n", "*number", "*l", "*a"))
    io.input("data.txt")
-   print(io.read("n", "number", "l", "a"))
+   print("io.read()", io.read("n", "number", "l", "a"))
    io.input(io.stdin)
+   if mode ~= "module" then
+     local f = assert(io.open("data.txt", "r"))
+     print("file:read()", f:read("*n", "*number", "*l", "*a"))
+     f:close()
+     f = assert(io.open("data.txt", "r"))
+     print("file:read()", f:read("n", "number", "l", "a"))
+     f:close()
+   end
    os.remove("data.txt")
 end
 
@@ -580,7 +588,7 @@ do
      end
      f:close()
      f = assert(io.open("data.txt", "r"))
-     for n1,n2,rest in f:lines("*n", "*n", "*a") do
+     for n1,n2,rest in f:lines("*n", "n", "*a") do
         print("file:lines()", n1, n2, rest)
      end
      f:close()