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Groups > comp.lang.c > #167723
| From | Keith Thompson <Keith.S.Thompson+u@gmail.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Cake - C23 to C99 transpiler |
| Date | 2022-09-14 10:59 -0700 |
| Organization | None to speak of |
| Message-ID | <87k065hm68.fsf@nosuchdomain.example.com> (permalink) |
| References | (11 earlier) <tfanqb$1gk1$1@gioia.aioe.org> <8735d380ta.fsf@bsb.me.uk> <tfate1$r6$1@gioia.aioe.org> <87tu5ikivi.fsf@nosuchdomain.example.com> <86tu5am4a9.fsf@linuxsc.com> |
Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
> Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:
>> Bart <bc@freeuk.com> writes:
>> [...]
>>
>>> Also, gcc gets away with allowing $ by default; tcc generally copies
>>> gcc in terms of how a compiler is invoked, so this surprisingly goes
>>> against that.
>>
>> gcc allowing $ in identifiers is a documented extension for most
>> targets, so it doesn't warn about them even with "-pedantic". One could
>> argue that this isn't necessarily an "extension", since "other
>> implementation-defined characters" are explicitly permitted by C11
>> 6.4.2.1.
>>
>> Interestingly, the C23 draft doesn't have that wording. Instead, it
>> allows XID_Start and XID_Continue characters, so it expands the set of
>> characters that *all* implementations must support,
>
> I believe that conclusion is not correct. The C23 draft n3047 says
> this:
>
> An XID_Start character is an implementation-defined character
> whose corresponding code point in ISO/IEC 10646 has the
> XID_Start property. An XID_Continue character is an
> implementation-defined character whose corresponding code point
> in ISO/IEC 10646 has the XID_Continue property.
>
> The presence of the modifying adjective "implementation-defined" in
> both cases surely means, at the very least, that implementations
> are allowed to subset the Unicode-specified XID_Start/XID_Continue
> sets with regard to what characters are allowed in identifiers.
You're right. I managed to miss the phrase "implementation-defined".
So ISO/IEC 10646 defines which characters have the "XID_Start" property,
but an "XID_Start" character is a member of a C implementation-defined
subset of those characters. The terminology is a bit confusing, but I'm
not sure how I'd improve it.
>> but doesn't permit '$' (assuming '$' isn't in XID_Start or
>> XID_Continue).
>
> I'm not sure this statement is right either (and agreeing with the
> assumption that '$' is not in XID_Start or XID_Continue). The
> Unicode reference documentation is so bad that I can't make out
> with any degree of certainty whether it allows various domains to
> extend the XID_Start/XID_Continue sets for the application in
> question. The presence of "implementation-defined" further muddies
> the waters. To be clear, neither am I saying that I think the
> statement is wrong; only that at present there is not enough
> information to be confident of either conclusion.
If '$' can't be an XID_Start or XID_Continue character, then an attempt
to use '$' in an identifier is a syntax error. I don't see any wiggle
room there. The open question is whether '$' is, or can be, an
XID_Start or XID_Continue character.
[...]
--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Working, but not speaking, for Philips
void Void(void) { Void(); } /* The recursive call of the void */
Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Cake - C23 to C99 transpiler Thiago Adams <thiago.adams@gmail.com> - 2022-08-18 18:44 -0700
Re: Cake - C23 to C99 transpiler Blue-Maned_Hawk <bluemanedhawk@example.invalid> - 2022-09-06 02:48 -0400
Re: Cake - C23 to C99 transpiler Thiago Adams <thiago.adams@gmail.com> - 2022-09-06 10:08 -0700
Re: Cake - C23 to C99 transpiler Vir Campestris <vir.campestris@invalid.invalid> - 2022-09-07 12:27 +0100
Re: Cake - C23 to C99 transpiler Thiago Adams <thiago.adams@gmail.com> - 2022-09-07 05:45 -0700
Re: Cake - C23 to C99 transpiler Bart <bc@freeuk.com> - 2022-09-07 15:35 +0100
Re: Cake - C23 to C99 transpiler Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-07 16:38 +0100
Re: Cake - C23 to C99 transpiler Bart <bc@freeuk.com> - 2022-09-07 17:04 +0100
Re: Cake - C23 to C99 transpiler Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-09-07 19:14 +0300
Re: Cake - C23 to C99 transpiler Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-07 17:31 +0100
Re: Cake - C23 to C99 transpiler Bart <bc@freeuk.com> - 2022-09-07 17:40 +0100
Re: Cake - C23 to C99 transpiler Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-07 17:49 +0100
Re: Cake - C23 to C99 transpiler Bart <bc@freeuk.com> - 2022-09-07 19:27 +0100
Re: Cake - C23 to C99 transpiler Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-07 20:02 +0100
Re: Cake - C23 to C99 transpiler Bart <bc@freeuk.com> - 2022-09-07 21:03 +0100
Re: Cake - C23 to C99 transpiler Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-07 13:52 -0700
Re: Cake - C23 to C99 transpiler Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-14 07:14 -0700
Re: Cake - C23 to C99 transpiler Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-14 10:59 -0700
Re: Cake - C23 to C99 transpiler Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-15 23:46 -0700
Re: Cake - C23 to C99 transpiler David Brown <david.brown@hesbynett.no> - 2022-09-07 20:17 +0200
Re: Cake - C23 to C99 transpiler Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-07 19:58 +0100
Re: Cake - C23 to C99 transpiler Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-07 13:26 -0700
Re: Cake - C23 to C99 transpiler Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-07 23:42 +0100
Re: Cake - C23 to C99 transpiler Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-14 06:45 -0700
Re: Cake - C23 to C99 transpiler Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-14 06:40 -0700
Re: Cake - C23 to C99 transpiler Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-07 10:28 -0700
Re: Cake - C23 to C99 transpiler David Brown <david.brown@hesbynett.no> - 2022-09-07 20:05 +0200
Re: Cake - C23 to C99 transpiler Thiago Adams <thiago.adams@gmail.com> - 2022-09-07 15:28 -0700
Re: Cake - C23 to C99 transpiler Bart <bc@freeuk.com> - 2022-09-08 00:51 +0100
Re: Cake - C23 to C99 transpiler Thiago Adams <thiago.adams@gmail.com> - 2022-09-08 05:20 -0700
Re: Cake - C23 to C99 transpiler Bart <bc@freeuk.com> - 2022-09-08 16:41 +0100
Re: Cake - C23 to C99 transpiler scott@slp53.sl.home (Scott Lurndal) - 2022-09-08 16:43 +0000
Re: Cake - C23 to C99 transpiler Bart <bc@freeuk.com> - 2022-09-08 19:23 +0100
Re: Cake - C23 to C99 transpiler Thiago Adams <thiago.adams@gmail.com> - 2022-09-08 09:59 -0700
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