trigraphs in X3J11

Doug Gwyn gwyn at brl-smoke.ARPA
Fri May 27 02:23:48 AEST 1988


In article <10941 at steinmetz.ge.com> davidsen at crdos1.UUCP (bill davidsen) writes:
>	#trigraph ??

This is a nice idea, assuming that one remains committed to having the
compiler deal with trigraphs at all, which in my opinion was never
necessary even for European C users.

There have been further ISO developments affecting character sets
since the invention of trigraphs, so it might be appropriate to
rexamine this invention to see whether or not it could be totally
removed.  However, at this stage of the approval process, the only
way I can imagine a substantive change to the trigraph specs would
be for a serious objection ("veto") to be raised at the ISO level.
X3J11 has indicated a desire for the next round of public review
to be the last, which it cannot be if substantive changes are made.

>  PLEASE X3J11, fix this sucker! It CAN be done without breaking
>existing programs.  It makes more sense in the preprocessor.  Best
>reason is that as specified it will lead to compilers which don't do
>full ANSI by default, or even subset compilers. 

Trigraph mapping is specified as being done in translation phase 1,
which precedes what is normally considered "preprocessing", but could
certainly be handled by separate preprocessors.  I think your proposal
could be fit into the translation-phase scheme adequately if it were
accepted by the committee.

I don't really think there will be any compilers that will fully
conform to all ANSI/ISO C specs, except for trigraph handling, as
the default case.  Much more likely is that there would be separate
PCC-like and ANSI-conforming compilers (perhaps controlled by a
command-line "switch").



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