Re: bug in lua lexer

[Glenn Maynard <glenn@...>]

On Mon, Dec 05, 2005 at 01:30:38PM -0500, John Passaniti wrote:
> Antero Vipunen wrote:
> >Lua lexer treats dot `.' as separator. But relies (by default) on 
> >strtod() for converting, and thus if your ``local'' separator is `,', 
> >you are unable to compile the following sample program:

I can think of four solutions, and they're all ugly:

#1: Lua rolls its own conversion.  Bloats the code, but can be omitted
    on embedded platforms where strtod() will do what's expected.
#2: Figure out the locale separator, and adjust strings being parsed.
     sprintf(s, "%f", 1.0f); s[1];
   That may mean making a copy of the string to replace into, but only
   if s[1] != '.'.  The result could be cached in a static (to avoid an
   sprintf() for every call), but that would break if the locale changes.
#3: Say "it's up to the application to handle setting LC_NUMERIC to a locale
   whose separator is '.'".  That's bad.  It might be a library using Lua, in
   which case the requirement infects other libraries.  It may be very
   difficult for an application to arrange for it to be safe to temporarily
   set LC_NUMERIC.  Lua can parse during normal execution, so in the general
   case this would have to be done for all Lua execution, not just parsing.
   Finally, it's wrong; Lua code might actually want to use LC_NUMERIC with
   locale separators.
#4: Call setlocale() to set LC_NUMERIC to "C" during lexing.  Libraries
   shouldn't touch the locale, since it's not threadsafe, and it's nonportable.

I think #1 and #2 are reasonable, and #3 and #4 aren't.  Any better options?

-- 
Glenn Maynard