--
-- Compat-5.1
-- Copyright Kepler Project 2004-2006 (http://www.keplerproject.org/compat)
-- According to Lua 5.1
-- $Id: compat-5.1.lua,v 1.22 2006/02/20 21:12:47 carregal Exp $
--
-- Copyright © 2004-2006 The Kepler Project.
--   
-- 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.   
--

_COMPAT51 = "Compat-5.1 R5"

local LUA_DIRSEP = '/'
local LUA_OFSEP = '_'
local OLD_LUA_OFSEP = ''
local POF = 'luaopen_'
local LUA_PATH_MARK = '?'
local LUA_IGMARK = ':'

local assert, error, getfenv, ipairs, loadfile, loadlib, pairs, setfenv, setmetatable, type = assert, error, getfenv, ipairs, loadfile, loadlib, pairs, setfenv, setmetatable, type
local find, format, gfind, gsub, sub = string.find, string.format, string.gfind, string.gsub, string.sub

--
-- avoid overwriting the package table if it's already there
--
package = package or {}
local _PACKAGE = package

package.path = LUA_PATH or os.getenv("LUA_PATH") or
             ("./?.lua;" ..
              "/usr/local/share/lua/5.0/?.lua;" ..
              "/usr/local/share/lua/5.0/?/?.lua;" ..
              "/usr/local/share/lua/5.0/?/init.lua" )
 
package.cpath = LUA_CPATH or os.getenv("LUA_CPATH") or
             "./?.so;" ..
             "./l?.so;" ..
             "/usr/local/lib/lua/5.0/?.so;" ..
             "/usr/local/lib/lua/5.0/l?.so"

--
-- make sure require works with standard libraries
--
package.loaded = package.loaded or {}
package.loaded.debug = debug
package.loaded.string = string
package.loaded.math = math
package.loaded.io = io
package.loaded.os = os
package.loaded.table = table 
package.loaded.base = _G
package.loaded.coroutine = coroutine
local _LOADED = package.loaded

--
-- avoid overwriting the package.preload table if it's already there
--
package.preload = package.preload or {}
local _PRELOAD = package.preload


--
-- looks for a file `name' in given path
--
local function findfile (name, pname)
	name = gsub (name, "%.", LUA_DIRSEP)
	local path = _PACKAGE[pname]
	assert (type(path) == "string", format ("package.%s must be a string", pname))
	for c in gfind (path, "[^;]+") do
		c = gsub (c, "%"..LUA_PATH_MARK, name)
		local f = io.open (c)
		if f then
			f:close ()
			return c
		end
	end
	return nil -- not found
end


--
-- check whether library is already loaded
--
local function loader_preload (name)
	assert (type(name) == "string", format (
		"bad argument #1 to `require' (string expected, got %s)", type(name)))
	assert (type(_PRELOAD) == "table", "`package.preload' must be a table")
	return _PRELOAD[name]
end


--
-- Lua library loader
--
local function loader_Lua (name)
	assert (type(name) == "string", format (
		"bad argument #1 to `require' (string expected, got %s)", type(name)))
	local filename = findfile (name, "path")
	if not filename then
		return false
	end
	local f, err = loadfile (filename)
	if not f then
		error (format ("error loading module `%s' (%s)", name, err))
	end
	return f
end


local function mkfuncname (name)
	name = gsub (name, "^.*%"..LUA_IGMARK, "")
	name = gsub (name, "%.", LUA_OFSEP)
	return POF..name
end

local function old_mkfuncname (name)
	--name = gsub (name, "^.*%"..LUA_IGMARK, "")
	name = gsub (name, "%.", OLD_LUA_OFSEP)
	return POF..name
end

--
-- C library loader
--
local function loader_C (name)
	assert (type(name) == "string", format (
		"bad argument #1 to `require' (string expected, got %s)", type(name)))
	local filename = findfile (name, "cpath")
	if not filename then
		return false
	end
	local funcname = mkfuncname (name)
	local f, err = loadlib (filename, funcname)
	if not f then
		funcname = old_mkfuncname (name)
		f, err = loadlib (filename, funcname)
		if not f then
			error (format ("error loading module `%s' (%s)", name, err))
		end
	end
	return f
end


local function loader_Croot (name)
	local p = gsub (name, "^([^.]*).-$", "%1")
	if p == "" then
		return
	end
	local filename = findfile (p, "cpath")
	if not filename then
		return
	end
	local funcname = mkfuncname (name)
	local f, err, where = loadlib (filename, funcname)
	if f then
		return f
	elseif where ~= "init" then
		error (format ("error loading module `%s' (%s)", name, err))
	end
end

-- create `loaders' table
package.loaders = package.loaders or { loader_preload, loader_Lua, loader_C, loader_Croot, }
local _LOADERS = package.loaders


--
-- iterate over available loaders
--
local function load (name, loaders)
	-- iterate over available loaders
	assert (type (loaders) == "table", "`package.loaders' must be a table")
	for i, loader in ipairs (loaders) do
		local f = loader (name)
		if f then
			return f
		end
	end
	error (format ("module `%s' not found", name))
end

-- sentinel
local sentinel = function () end

--
-- new require
--
function _G.require (modname)
	assert (type(modname) == "string", format (
		"bad argument #1 to `require' (string expected, got %s)", type(name)))
	local p = _LOADED[modname]
	if p then -- is it there?
		if p == sentinel then
			error (format ("loop or previous error loading module '%s'", modname))
		end
		return p -- package is already loaded
	end
	local init = load (modname, _LOADERS)
	_LOADED[modname] = sentinel
	local actual_arg = _G.arg
	_G.arg = { modname }
	local res = init (modname)
	if res then
		_LOADED[modname] = res
	end
	_G.arg = actual_arg
	if _LOADED[modname] == sentinel then
		_LOADED[modname] = true
	end
	return _LOADED[modname]
end


-- findtable
local function findtable (t, f)
	assert (type(f)=="string", "not a valid field name ("..tostring(f)..")")
	local ff = f.."."
	local ok, e, w = find (ff, '(.-)%.', 1)
	while ok do
		local nt = rawget (t, w)
		if not nt then
			nt = {}
			t[w] = nt
		elseif type(t) ~= "table" then
			return sub (f, e+1)
		end
		t = nt
		ok, e, w = find (ff, '(.-)%.', e+1)
	end
	return t
end

--
-- new package.seeall function
--
function _PACKAGE.seeall (module)
	local t = type(module)
	assert (t == "table", "bad argument #1 to package.seeall (table expected, got "..t..")")
	local meta = getmetatable (module)
	if not meta then
		meta = {}
		setmetatable (module, meta)
	end
	meta.__index = _G
end


--
-- new module function
--
function _G.module (modname, ...)
	local ns = _LOADED[modname]
	if type(ns) ~= "table" then
		ns = findtable (_G, modname)
		if not ns then
			error (string.format ("name conflict for module '%s'", modname))
		end
		_LOADED[modname] = ns
	end
	if not ns._NAME then
		ns._NAME = modname
		ns._M = ns
		ns._PACKAGE = gsub (modname, "[^.]*$", "")
	end
	setfenv (2, ns)
	for i, f in ipairs (arg) do
		f (ns)
	end
end
