Re: Lua plans to add meta-programming support?

[Luiz Henrique de Figueiredo <lhf@...>]

> so if  Lua can provider a oken-filter

Adding a token filter to Lua 5.2 remains just as easy as it was in Lua 5.1:

1. get a copy of llex.c.
2. add <<#include "proxy.c">> just before the definition of luaX_next in llex.c.
3. write a filter in proxy.c. It can be one that does simple token shuffling
   or a generic one that calls Lua. Token filters written in C tend to be
   easy to get right for simple tasks such as say allowing reserved words
   as field names. See the code below.
4. rebuild Lua and enjoy.

/*
* proxy.c
* lexer proxy for Lua parser -- allows reserved words as field names
* Luiz Henrique de Figueiredo <lhf@tecgraf.puc-rio.br>
* 18 Nov 2010 14:59:04
* This code is hereby placed in the public domain.
* Add <<#include "proxy.c">> just before the definition of luaX_next in llex.c
*/

#define LAST_RESERVED TK_WHILE

static int nexttoken(LexState *ls, SemInfo *seminfo)
{
 static int last=TK_EOS;
 int t=llex(ls,seminfo);
 if (last=='.' && t>=FIRST_RESERVED && t<=LAST_RESERVED) {
 	return TK_NAME;
 }
 last=t;
 return t;
}

#define llex nexttoken