1 files changed, 103 insertions, 0 deletions

diff --git a/compat53/init.lua b/compat53/init.lua
new file mode 100644
index 0000000..cdd5f34
--- /dev/null
+++ b/compat53/init.lua
@@ -0,0 +1,103 @@
+local _G, _VERSION, type, pairs, require =
+      _G, _VERSION, type, pairs, require
+
+local M = require("compat53.base")
+local lua_version = _VERSION:sub(-3)
+
+
+-- apply other global effects
+if lua_version == "5.1" then
+
+   -- cache globals
+   local error, rawset, select, setmetatable, type, unpack =
+         error, rawset, select, setmetatable, type, unpack
+   local debug, io, package, string = debug, io, package, string
+   local io_type, io_stdout = io.type, io.stdout
+
+   -- select the most powerful getmetatable function available
+   local gmt = type(debug) == "table" and debug.getmetatable or
+               getmetatable or function() return false end
+
+   -- detect LuaJIT (including LUAJIT_ENABLE_LUA52COMPAT compilation flag)
+   local is_luajit = (string.dump(function() end) or ""):sub(1, 3) == "\027LJ"
+
+
+   -- 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
+            rawset(p, k, v)
+         end
+      end
+   })
+
+
+   if not is_luajit then
+      local function helper(st, var_1, ...)
+         if var_1 == nil then
+            if (...) ~= nil then
+               error((...), 2)
+            end
+         end
+         return var_1, ...
+      end
+
+      local function lines_iterator(st)
+         return helper(st, st.f:read(unpack(st, 1, st.n)))
+      end
+
+      local valid_format = { ["*l"] = true, ["*n"] = true, ["*a"] = true }
+
+      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
+            else
+               return nil, msg, errno
+            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
+
+end -- lua == 5.1
+
+
+-- handle exporting to global scope
+local function extend_table(from, to)
+   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
+
+extend_table(M, _G)
+
+return _G
+
+-- vi: set expandtab softtabstop=3 shiftwidth=3 :