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Re: pointers

From BartC <bc@freeuk.com>
Newsgroups comp.lang.c
Subject Re: pointers
Date 2016-10-25 23:06 +0100
Organization A noiseless patient Spider
Message-ID <nuol16$idr$1@dont-email.me> (permalink)
References (11 earlier) <ln60ohblkv.fsf@kst-u.example.com> <nulp42$nqg$1@dont-email.me> <lnshrla4et.fsf@kst-u.example.com> <num3c9$jso$1@dont-email.me> <lnlgxc88q0.fsf@kst-u.example.com>

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On 25/10/2016 21:38, Keith Thompson wrote:
> BartC <bc@freeuk.com> writes:

>> No problem. I'm just intrigued. The language implementations I've done
>> work differently, that's all. Here's some of the examples in my
>> language (^ means dereference):
> [snip]
>
> Um, I think your answer is (c), but it's hard to tell.  Of course other
> languages are different; that's what makes them other languages.

The language I gave examples in isn't that different; it's at the same 
level as C and has to solve many of the same problems.

With the alternative approach to mixing & and *, the result is more 
expressiveness, fewer problems and more useful diagnostics (so you get a 
genuine error when the number of & or * is wrong for the type, not when 
you hit some arbitrary restriction in the language).

That C doesn't allow that expressiveness isn't a big deal as the terms 
involved can usually be rewritten into something that's legal.

But it does seem rather unsatisfactory given that in other places C 
/does/ allow any number of chained * ops which do not match the type of 
the term they operate on. Example:

f is a function with no associated pointers, but *f, **f, ***f are all 
legal. As is &**f. But not & &**f which ought to be equivalent of f.)

>> So there do appear to be advantages to doing things the way I've suggested.
>
> There's no point in discussing any advantages until we understand what
> the standard currently says.

The advantage is obvious. You don't need to explain why &*p is allowed 
but not & &**p or *&p!

-- 
Bartc

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Thread

pointers asetofsymbols@gmail.com - 2016-10-23 08:11 -0700
  Re: pointers Richard Heathfield <rjh@cpax.org.uk> - 2016-10-23 16:26 +0100
    Re: pointers asetofsymbols@gmail.com - 2016-10-23 10:35 -0700
      Re: pointers Ike Naar <ike@iceland.freeshell.org> - 2016-10-23 17:47 +0000
        Re: pointers asetofsymbols@gmail.com - 2016-10-25 12:55 -0700
      Re: pointers "James R. Kuyper" <jameskuyper@verizon.net> - 2016-10-23 13:58 -0400
        Re: pointers BartC <bc@freeuk.com> - 2016-10-24 00:55 +0100
          Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-23 17:27 -0700
            Re: pointers BartC <bc@freeuk.com> - 2016-10-24 11:53 +0100
              Re: pointers supercat@casperkitty.com - 2016-10-24 07:29 -0700
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 08:55 -0700
                Re: pointers Tim Rentsch <txr@alumni.caltech.edu> - 2016-10-24 14:02 -0700
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 14:42 -0700
                Re: pointers Tim Rentsch <txr@alumni.caltech.edu> - 2016-10-25 08:56 -0700
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-25 12:17 -0700
                Re: pointers Tim Rentsch <txr@alumni.caltech.edu> - 2016-10-26 06:37 -0700
              Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 08:49 -0700
                Re: pointers BartC <bc@freeuk.com> - 2016-10-24 17:25 +0100
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 09:52 -0700
                Re: pointers BartC <bc@freeuk.com> - 2016-10-24 18:15 +0100
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 12:20 -0700
                Re: pointers BartC <bc@freeuk.com> - 2016-10-24 20:58 +0100
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 13:16 -0700
                Re: pointers BartC <bc@freeuk.com> - 2016-10-24 23:53 +0100
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-25 13:38 -0700
                Re: pointers BartC <bc@freeuk.com> - 2016-10-25 23:06 +0100
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-25 15:39 -0700
                Re: pointers BartC <bc@freeuk.com> - 2016-10-26 00:26 +0100
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-25 16:44 -0700
                Re: pointers BartC <bc@freeuk.com> - 2016-10-26 01:02 +0100
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-25 17:35 -0700
                Re: pointers Ike Naar <ike@iceland.freeshell.org> - 2016-10-26 06:27 +0000
                Re: pointers BartC <bc@freeuk.com> - 2016-10-26 12:47 +0100
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-26 09:05 -0700
                Re: pointers BartC <bc@freeuk.com> - 2016-10-26 18:46 +0100
                Re: pointers supercat@casperkitty.com - 2016-10-26 11:44 -0700
                Re: pointers BartC <bc@freeuk.com> - 2016-10-26 20:12 +0100
                Re: pointers BartC <bc@freeuk.com> - 2016-10-26 20:30 +0100
                Re: pointers supercat@casperkitty.com - 2016-10-26 13:02 -0700
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-26 11:52 -0700
                Re: pointers Ike Naar <ike@iceland.freeshell.org> - 2016-10-26 19:11 +0000
                Re: pointers BartC <bc@freeuk.com> - 2016-10-26 21:25 +0100
                Re: pointers "James R. Kuyper" <jameskuyper@verizon.net> - 2016-10-25 18:56 -0400
                Re: pointers "James R. Kuyper" <jameskuyper@verizon.net> - 2016-10-25 19:12 -0400
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-25 16:31 -0700
                Re: pointers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-10-24 21:36 +0100
                Re: pointers BartC <bc@freeuk.com> - 2016-10-25 16:54 +0100
                Re: pointers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-10-25 19:09 +0100
                Re: pointers supercat@casperkitty.com - 2016-10-24 11:33 -0700
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 12:22 -0700
          Re: pointers James Kuyper <jameskuyper@verizon.net> - 2016-10-24 10:23 -0400
  Re: pointers "James R. Kuyper" <jameskuyper@verizon.net> - 2016-10-23 12:31 -0400
    Re: pointers Richard Heathfield <rjh@cpax.org.uk> - 2016-10-23 17:38 +0100
  Re: pointers Lorinczy Zsigmond <zsiga@nospam.for.me> - 2016-10-24 14:02 +0200
  Re: pointers John Bode <jfbode1029@gmail.com> - 2016-10-24 13:34 -0700

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