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| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Why _Bool was not defined as enum in C99? |
| Date | 2016-09-15 13:40 -0700 |
| Organization | None to speak of |
| Message-ID | <lnoa3o3ni6.fsf@kst-u.example.com> (permalink) |
| References | (3 earlier) <kfnmvjaiwbw.fsf@x-alumni2.alumni.caltech.edu> <lnlgyu5qin.fsf@kst-u.example.com> <kfneg4miar7.fsf@x-alumni2.alumni.caltech.edu> <ln8tuu5h4x.fsf@kst-u.example.com> <kfn1t0lhwzn.fsf@x-alumni2.alumni.caltech.edu> |
Tim Rentsch <txr@alumni.caltech.edu> writes:
[...]
> I'm not sure we have a disagreement. (To be fair I guess I
> should add that I'm not sure we don't either.) Do you think
> that _Bool /should/ have been made an enumerated type? If not
> then AFAIAC we are in agreement on the salient question here,
> and there is no need to inquire further.
If we have a disagreement, it's a trivial one. I think that defining
_Bool as an enumerated type would have been reasonably sensible,
but I have no particular problem with the choice the committee made
here in the real world. You, as I understand it, think that defining
_Bool as an enumerated type would have been a bad idea conceptually.
And of course neither of us thinks it should be changed now.
But as I write this, I've actually changed my mind.
The approach I had in mind was to do the equivalent of
typedef enum { false, true } _Bool;
but making it predefined. <stdbool.h> would still define the
identifier "bool" as an alias (macro, typedef, whatever) for _Bool.
But I just realized that would make the identifiers "false" and
"true" universally visible, causing problems for existing pre-C99
code that defines those identifiers. I suppose that could be solved
by predefining
typedef enum { _False, _True } _Bool;
and then defining, false, true, and bool as macros in <stdbool.h>.
That's ugly enough IMHO to tip the balance in favor of the actual
C99 approach.
The point of making _Bool an enumeration type was to have a clean
(IMHO) way to define false and true -- but there was no good way
to do that without breaking existing code.
I don't know whether the committee thought about that particular
issue.
<emily_litella>Never mind.</emily_litella>
(If I were designing a new language with no concern for backward
compatibility, I'd likely make `bool`, `false`, and `true` all
keywords, as C++ has done. There might have been an opportunity
to do that in C89, but I'd say C99 was too late.)
--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Why _Bool was not defined as enum in C99? thiago.adams@gmail.com - 2016-09-12 13:24 -0700
Re: Why _Bool was not defined as enum in C99? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-12 21:56 +0100
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-12 15:59 -0700
Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-13 16:05 -0700
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-13 18:17 -0700
Re: Why _Bool was not defined as enum in C99? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-14 01:20 +0100
Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-14 03:59 -0700
Re: Why _Bool was not defined as enum in C99? Nobody <nobody@nowhere.invalid> - 2016-09-14 17:31 +0100
Re: Why _Bool was not defined as enum in C99? Thiago Adams <thiago.adams@gmail.com> - 2016-09-14 09:49 -0700
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-14 11:45 -0700
Re: Why _Bool was not defined as enum in C99? <william@wilbur.25thandClement.com> - 2016-09-14 14:13 -0700
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-14 16:26 -0700
Re: Why _Bool was not defined as enum in C99? "James R. Kuyper" <jameskuyper@verizon.net> - 2016-09-12 17:11 -0400
Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-13 15:55 -0700
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-13 18:08 -0700
Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-14 03:56 -0700
Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-14 07:58 -0700
Re: Why _Bool was not defined as enum in C99? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-14 19:39 +0100
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-14 13:52 -0700
Re: Why _Bool was not defined as enum in C99? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-15 00:53 +0100
Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-14 17:04 -0700
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-14 20:52 -0700
Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-14 19:26 -0700
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-14 19:04 -0700
Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-14 14:21 -0700
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-14 16:23 -0700
Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-14 17:06 -0700
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-14 20:45 -0700
Re: Why _Bool was not defined as enum in C99? Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-14 22:12 -0400
Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-15 12:37 +0200
Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-15 09:35 -0700
Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 00:47 +0200
Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-15 22:02 -0700
Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 09:56 +0200
Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-16 07:34 -0700
Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 20:31 +0200
Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-16 12:32 -0700
Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-17 23:30 +0200
Re: Why _Bool was not defined as enum in C99? BartC <bc@freeuk.com> - 2016-09-15 18:25 +0100
Re: Why _Bool was not defined as enum in C99? luser droog <luser.droog@gmail.com> - 2016-09-15 12:35 -0700
Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 00:51 +0200
Re: Why _Bool was not defined as enum in C99? luser droog <luser.droog@gmail.com> - 2016-09-16 17:02 -0700
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-16 19:23 -0700
Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-17 23:35 +0200
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-14 10:40 -0700
Re: Why _Bool was not defined as enum in C99? Thiago Adams <thiago.adams@gmail.com> - 2016-09-14 10:01 -0700
Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-14 11:35 -0700
Re: Why _Bool was not defined as enum in C99? Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-14 22:15 -0400
Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-14 23:51 -0700
Re: Why _Bool was not defined as enum in C99? Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-15 15:14 -0400
Re: Why _Bool was not defined as enum in C99? Ian Collins <ian-news@hotmail.com> - 2016-09-15 16:08 +1200
Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-15 12:46 +0200
Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-15 09:37 -0700
Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 00:53 +0200
Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-15 21:45 -0700
Re: Why _Bool was not defined as enum in C99? Richard Heathfield <rjh@cpax.org.uk> - 2016-09-16 06:32 +0100
Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 09:59 +0200
Re: Why _Bool was not defined as enum in C99? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-16 11:00 +0100
Re: Why _Bool was not defined as enum in C99? Thiago Adams <thiago.adams@gmail.com> - 2016-09-16 04:46 -0700
Re: Why _Bool was not defined as enum in C99? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-16 12:58 +0100
Re: Why _Bool was not defined as enum in C99? Melzzzzz <Melzzzzz@zzzzz.com> - 2016-09-16 12:06 +0000
Re: Why _Bool was not defined as enum in C99? Thiago Adams <thiago.adams@gmail.com> - 2016-09-16 05:13 -0700
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-16 10:47 -0700
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-16 10:46 -0700
Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 10:02 +0200
Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-15 11:42 -0700
Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 10:19 +0200
Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-16 08:06 -0700
Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 20:51 +0200
Re: Why _Bool was not defined as enum in C99? Thiago Adams <thiago.adams@gmail.com> - 2016-09-16 11:56 -0700
Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-22 22:38 -0700
Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-14 11:42 -0700
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-14 14:02 -0700
Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-15 10:51 -0700
Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-15 11:18 -0700
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-15 13:46 -0700
Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-15 13:10 -0700
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-15 16:01 -0700
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-15 13:40 -0700
Re: Why _Bool was not defined as enum in C99? Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-16 07:21 -0700
Re: Why _Bool was not defined as enum in C99? Thiago Adams <thiago.adams@gmail.com> - 2016-09-16 07:37 -0700
Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-16 20:55 +0200
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-16 14:43 -0700
Re: Why _Bool was not defined as enum in C99? supercat@casperkitty.com - 2016-09-16 15:36 -0700
Re: Why _Bool was not defined as enum in C99? David Brown <david.brown@hesbynett.no> - 2016-09-17 23:45 +0200
Re: Why _Bool was not defined as enum in C99? Keith Thompson <kst-u@mib.org> - 2016-09-17 17:14 -0700
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