Re: luac & 5.2?
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- Subject: Re: luac & 5.2?
- From: "Robert G. Jakabosky" <bobby@...>
- Date: 2012年3月30日 15:30:44 -0700
On Friday 30, Petite Abeille wrote:
> On Mar 30, 2012, at 11:22 PM, Petite Abeille wrote:
> > But now when running the resulting Nanoki.luac in 5.2, I get the following
exception:
> For what's worth, here is a self-contained example of the issue:
>
>
> $ cat TestA.lua
> local print = print
>
> module( 'TestA' )
>
> print( _NAME )
>
>
> $ cat TestB.lua
> local print = print
>
> module( 'TestB' )
>
> print( _NAME )
>
>
> $ cat TestC.lua
> local TestA = require( 'TestA' )
> local TestB = require( 'TestB' )
>
> print( 'TestC' )
>
>
> $ lua -v TestC.lua
> Lua 5.2.0 Copyright (C) 1994-2011 Lua.org, PUC-Rio
> TestA
> TestB
> TestC
>
>
> $ luac -o TestC.luac TestA.lua TestB.lua TestC.lua
>
>
> $ lua TestC.luac
> TestA
> lua: TestB.lua:3: attempt to call global 'module' (a nil value)
> stack traceback:
> TestB.lua:3: in main chunk
> (luac): in main chunk
> [C]: in ?
>
>
> Thoughts?
luac is combining those files into this:
-- TestA.lua
(function()
local print = print
-- first call to module. Under Lua 5.2 it changes _ENV for the
-- whole compiled group of files.
module( 'TestA' )
print( _NAME )
end)()
-- TestB.lua
(function()
local print = print
module( 'TestB' )
print( _NAME )
end)()
-- TestC.lua
(function()
local TestA = require( 'TestA' )
local TestB = require( 'TestB' )
print( 'TestC' )
end)()
In Lua 5.1 the 'module' call only affects the anonymous (function()end)
function's environment. In Lua 5.2 all of the (function()end) blocks share
one _ENV up value. So the first call to module() in TestA.lua changes the
_ENV for all the other modules.
One solution would be to add this code:
local _ENV = original_ENV
before each (function() ...... end)() block. "original_ENV" would have to be
saved at the start:
local original_ENV = _ENV
Or to wrap each block with a do/end block:
do
local _ENV = _ENV
(function()
--- files code
end)()
end
This could be done by modifying the Lua compiler written in Lua [1].
1. http://lua-users.org/wiki/LuaCompilerInLua
--
Robert G. Jakabosky