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[Bug preprocessor/9449] UCNs not recognized in identifiers (c++/c99)


------- Additional Comments From joseph at codesourcery dot com  2005-09-15 22:53 -------
Subject: Re:  UCNs not recognized in identifiers
 (c++/c99)

On Thu, 15 Sep 2005, geoffk at gcc dot gnu dot org wrote:

> ------- Additional Comments From geoffk at gcc dot gnu dot org  2005-09-15 22:34 -------
> (In reply to comment #39)
> > Another reason why spelling needs preserving (in addition to implementing #
> > correctly) is for the constraints on duplicate macro definitions.
> > 
> > #define foo \u00c1
> > #define foo \u00C1
> > 
> > is invalid (different spelling in replacement), as is
> 
> We discussed this on the list and decided that this was probably a defect in the C standard, since the 
> Rationale says that the kind of implementation we have now is supposed to be permitted, and jsm said 
> he'd file a DR.  How's that going?

I don't believe I said I'd file a DR unless I saw a defect.  There is no 
defect because models A or C need to be implemented by an 
implementation-defined mapping (documented as such; we don't even document 
the removal of trailing whitespace from lines; of course anything 
replacing UCNs with the characters they designate only in certain places 
is a pain to document because it doesn't fit in with the C model of phases 
of translation).  Doug Gwyn's reading in reflector message 10751,

  Yes, "spelling" is meant in terms of the source code characters.
  The idea is to permit simple strcmp-like checking by the preprocessor.

seems fine to me - implementations permitting the above in the input 
source must end up with the source looking different from the above after 
phase 1.



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=9449


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