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Re: RFC: enum instead of #define for tokens
From: |
Hans Aberg |
Subject: |
Re: RFC: enum instead of #define for tokens |
Date: |
Wed, 3 Apr 2002 19:46:57 +0200 |
At 19:13 +0200 2002/04/03, Akim Demaille wrote:
>| 2. Currently Bison assumes 8-bit bytes (i.e. that UCHAR_MAX is 255).
I think this is a non-issue as nearly all machines use C/C++-bit bytes:
Those that used say 9 bits are archaic. If one uses 16-bit C/C++ bytes,
then file IO should also take place in those chunks according to the C/C++
standards.
So my compiler runs on a platform (or so a macro says) where a byte has 16
bits, but given the file IO question, I wonder if it really is conforming
on that platform.
>My position, probably not very nice, is that this should not happen.
>Passing chars (wchars) as tokens is wrong. It was a nice little dirty
>trick to be able to `return '+'' in the scanner, and use '+' too in
>the parser, but that's not sane. The parser should never see
>characters.
You are right, this is not very nice :-):
I think you are imposing your own programming style here.
I tweaked my bison.simple file so that when it encounters an unknown
character (known as a character by its range), it writes it out, instead of
just saying "undefined". One then can make full use of the Flex
. { return (unsigned char)yytext[0]; }
rule.
Very convenient: One spin-off is that one gets access to the error
reporting system of the Bison parser also for such characters.
>As a result, there is no such issue as a Unicode compliant parser.
Bison is already Yacc "char" compliant, starting at 257. So I think there
should be a corresponding Unicode feature: Unicode has so many characters,
that one needs a convenient way of handling them.
Hans Aberg
- RFC: enum instead of #define for tokens, Akim Demaille, 2002/04/02
- Re: RFC: enum instead of #define for tokens, Miles Bader, 2002/04/02
- RE: enum instead of #define for tokens, Wayne Green, 2002/04/02
- Re: RFC: enum instead of #define for tokens, Paul Eggert, 2002/04/02
- Re: RFC: enum instead of #define for tokens, Akim Demaille, 2002/04/03
- Re: RFC: enum instead of #define for tokens, Paul Eggert, 2002/04/03
- Re: RFC: enum instead of #define for tokens, Akim Demaille, 2002/04/03
- Re: RFC: enum instead of #define for tokens,
Hans Aberg <=
- Re: RFC: enum instead of #define for tokens, Akim Demaille, 2002/04/04
- Re: RFC: enum instead of #define for tokens, Hans Aberg, 2002/04/04
- Re: RFC: enum instead of #define for tokens, Akim Demaille, 2002/04/04
- Re: RFC: enum instead of #define for tokens, Hans Aberg, 2002/04/04
- Re: RFC: enum instead of #define for tokens, Anthony DeRobertis, 2002/04/04
- Re: RFC: enum instead of #define for tokens, Akim Demaille, 2002/04/05
- Re: RFC: enum instead of #define for tokens, Anthony DeRobertis, 2002/04/05
- Re: RFC: enum instead of #define for tokens, Akim Demaille, 2002/04/05
- Re: RFC: enum instead of #define for tokens, Paul Eggert, 2002/04/03
- Re: RFC: enum instead of #define for tokens, Miles Bader, 2002/04/03