Re: '$' as "valid" character in identifiers

[Derek M Jones <derek@knosof.co.uk>]

Al,

> The question is how do they treat $ in preprocessor tokens.  Is it a full
> equivalent of letter?  I.e. is $x a valid identifier?  If it is, that's
> easy - all we need is to add it cclass[] in tokenize.c as a letter and be
> done with that.  If not (i.e. if it can only appear after the first
> letter), we probably want to either classify it as digit or split the
> "Digit" bit in two and modify the code checking for it.  In any case,
> we need to figure out what to do with
> 
> #define A(x,y) x##y
> A(a,$b)
> 
> Either $b is an identifier, or it would better be a valid pp-number; otherwise,
> we'll get the second argument split in two tokens and get a$ b out of that
> macro.

Item 10 of http://www.open-std.org/jtc1/sc22/wg14/www/docs/n861.htm
gives some history and possible solutions.

If an implementation supports $ in identifiers, then it is an extension.
Implementation extensions are blessed in C99 provided they don't change
the behavior of strictly conforming programs.  Since $ is not in the
basic source character set a program that contains them is not strictly
conforming.

If sparse supports $ then it just has to do what the implementation it
is mimicing does.  There is no C Standard behavior as such to worry about.

-- 
Derek M. Jones                              tel: +44 (0) 1252 520 667
Knowledge Software Ltd                      mailto:derek@knosof.co.uk
Applications Standards Conformance Testing    http://www.knosof.co.uk