Re: Sugestions for runtime polymorphism

From	BartC <bc@freeuk.com>
Newsgroups	comp.lang.c
Subject	Re: Sugestions for runtime polymorphism
Date	2016-09-30 19:26 +0100
Organization	A noiseless patient Spider
Message-ID	<nsmaoa$sa0$1@dont-email.me> (permalink)
References	(10 earlier) <666af99b-9b6b-4f1a-a1a3-498ab48d6f44@googlegroups.com> <5be0e169-cd80-4785-b2c8-934e71cf1164@googlegroups.com> <kfnvaxeah6a.fsf@x-alumni2.alumni.caltech.edu> <05de4ed0-61b7-402e-91e6-cc4cd18069fa@googlegroups.com> <5dbd8c3a-110c-4b6c-8d3b-66e5486f2d32@googlegroups.com>

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On 30/09/2016 19:18, Thiago Adams wrote:
> On Friday, September 30, 2016 at 2:55:12 PM UTC-3, >
>
> What I would like to understand is why the operator -> was created and not just ".".
>
> void F(struct X* p)
> {
>    p.x = 1; //why not? p cannot have members
> }

This is a rare decision in C that I agree with. In C:

A[i];       // A could be an array, or a pointer (not to the array
             // but to one of its elements)

f();        // f could be a function, or pointer to function

And now you're proposing this:

p.m;        // p could be a struct, or a pointer to struct

How about keeping the language transparent?

But if .m can only used with actual structs, then (*p).m needs to be 
written when p is a pointer. That's too much so -> was introduced (or 
that's what everyone uses it for anyway).

-- 
Bartc

Thread

Sugestions for runtime polymorphism Thiago Adams <thiago.adams@gmail.com> - 2016-09-14 12:01 -0700
  Re: Sugestions for runtime polymorphism Thiago Adams <thiago.adams@gmail.com> - 2016-09-14 13:15 -0700
  Re: Sugestions for runtime polymorphism Thiago Adams <thiago.adams@gmail.com> - 2016-09-14 13:27 -0700
    Re: Sugestions for runtime polymorphism Richard Heathfield <rjh@cpax.org.uk> - 2016-09-14 21:50 +0100
      Re: Sugestions for runtime polymorphism Thiago Adams <thiago.adams@gmail.com> - 2016-09-14 14:20 -0700
        Re: Sugestions for runtime polymorphism "James R. Kuyper" <jameskuyper@verizon.net> - 2016-09-14 17:32 -0400
          Re: Sugestions for runtime polymorphism Keith Thompson <kst-u@mib.org> - 2016-09-14 16:30 -0700
            Re: Sugestions for runtime polymorphism "James R. Kuyper" <jameskuyper@verizon.net> - 2016-09-14 17:54 -0400
          Re: Sugestions for runtime polymorphism Thiago Adams <thiago.adams@gmail.com> - 2016-09-14 17:34 -0700
            Re: Sugestions for runtime polymorphism Thiago Adams <thiago.adams@gmail.com> - 2016-09-14 17:58 -0700
              Re: Sugestions for runtime polymorphism Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-14 19:50 -0700
                Re: Sugestions for runtime polymorphism Thiago Adams <thiago.adams@gmail.com> - 2016-09-15 05:03 -0700
              Re: Sugestions for runtime polymorphism BartC <bc@freeuk.com> - 2016-09-15 10:43 +0100
                Re: Sugestions for runtime polymorphism Thiago Adams <thiago.adams@gmail.com> - 2016-09-15 05:29 -0700
                Re: Sugestions for runtime polymorphism BartC <bc@freeuk.com> - 2016-09-15 19:49 +0100
                Re: Sugestions for runtime polymorphism Thiago Adams <thiago.adams@gmail.com> - 2016-09-15 11:58 -0700
                Re: Sugestions for runtime polymorphism BartC <bc@freeuk.com> - 2016-09-15 20:29 +0100
                Re: Sugestions for runtime polymorphism Thiago Adams <thiago.adams@gmail.com> - 2016-09-15 14:00 -0700
                Re: Sugestions for runtime polymorphism Thiago Adams <thiago.adams@gmail.com> - 2016-09-16 07:27 -0700
                Re: Sugestions for runtime polymorphism BartC <bc@freeuk.com> - 2016-09-16 16:34 +0100
                Re: Sugestions for runtime polymorphism Thiago Adams <thiago.adams@gmail.com> - 2016-09-16 09:36 -0700
                Re: Sugestions for runtime polymorphism Thiago Adams <thiago.adams@gmail.com> - 2016-09-20 12:59 -0700
                Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-09-20 14:08 -0700
                Re: Sugestions for runtime polymorphism Ian Collins <ian-news@hotmail.com> - 2016-09-21 15:53 +1200
                Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-09-21 07:38 -0700
                Re: Sugestions for runtime polymorphism Ian Collins <ian-news@hotmail.com> - 2016-09-23 09:12 +1200
                Re: Sugestions for runtime polymorphism Thiago Adams <thiago.adams@gmail.com> - 2016-09-21 05:26 -0700
                Re: Sugestions for runtime polymorphism Thiago Adams <thiago.adams@gmail.com> - 2016-09-21 05:35 -0700
                Re: Sugestions for runtime polymorphism Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-21 06:01 -0700
                Re: Sugestions for runtime polymorphism Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-22 01:44 -0700
                Re: Sugestions for runtime polymorphism BartC <bc@freeuk.com> - 2016-09-22 13:16 +0100
                Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-09-22 08:02 -0700
                Re: Sugestions for runtime polymorphism Keith Thompson <kst-u@mib.org> - 2016-09-22 11:44 -0700
                Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-09-22 09:52 -0700
                Re: Sugestions for runtime polymorphism David Brown <david.brown@hesbynett.no> - 2016-09-23 09:49 +0200
                Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-09-23 07:55 -0700
                Re: Sugestions for runtime polymorphism David Brown <david.brown@hesbynett.no> - 2016-09-24 16:29 +0200
                Re: Sugestions for runtime polymorphism Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-24 15:56 +0100
                Re: Sugestions for runtime polymorphism David Brown <david.brown@hesbynett.no> - 2016-09-24 17:50 +0200
                Re: Sugestions for runtime polymorphism "James R. Kuyper" <jameskuyper@verizon.net> - 2016-09-24 13:45 -0400
                Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-09-24 11:26 -0700
                Re: Sugestions for runtime polymorphism Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-28 10:38 -0700
                Re: Sugestions for runtime polymorphism Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-24 21:03 +0100
                Re: Sugestions for runtime polymorphism David Brown <david.brown@hesbynett.no> - 2016-09-25 12:43 +0200
                Re: Sugestions for runtime polymorphism "James R. Kuyper" <jameskuyper@verizon.net> - 2016-09-25 11:48 -0400
                Re: Sugestions for runtime polymorphism David Brown <david.brown@hesbynett.no> - 2016-09-25 18:39 +0200
                Re: Sugestions for runtime polymorphism "James R. Kuyper" <jameskuyper@verizon.net> - 2016-09-25 13:14 -0400
                Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-09-25 13:47 -0700
                Re: Sugestions for runtime polymorphism Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-28 10:39 -0700
                Re: Sugestions for runtime polymorphism David Brown <david.brown@hesbynett.no> - 2016-09-25 23:25 +0200
                Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-09-25 13:10 -0700
                Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-09-25 12:55 -0700
                Re: Sugestions for runtime polymorphism Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-25 20:38 +0100
                Re: Sugestions for runtime polymorphism David Brown <david.brown@hesbynett.no> - 2016-09-25 23:20 +0200
                Re: Sugestions for runtime polymorphism Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-28 07:15 -0700
                Re: Sugestions for runtime polymorphism David Brown <david.brown@hesbynett.no> - 2016-09-28 21:29 +0200
                Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-09-24 10:52 -0700
                Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-09-24 10:33 -0700
                Re: Sugestions for runtime polymorphism David Brown <david.brown@hesbynett.no> - 2016-09-25 12:46 +0200
                Re: Sugestions for runtime polymorphism Keith Thompson <kst-u@mib.org> - 2016-09-24 13:58 -0700
                Re: Sugestions for runtime polymorphism Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-28 04:46 -0700
                Re: Sugestions for runtime polymorphism Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-24 00:07 -0700
                Re: Sugestions for runtime polymorphism Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-23 08:52 -0700
                Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-09-23 09:56 -0700
                Re: Sugestions for runtime polymorphism Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-23 12:00 -0700
                Re: Sugestions for runtime polymorphism Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-22 08:45 -0700
                Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-09-22 09:36 -0700
                Re: Sugestions for runtime polymorphism Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-23 12:06 -0700
                Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-09-23 15:29 -0700
                Re: Sugestions for runtime polymorphism Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-29 07:56 -0700
                Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-09-30 10:54 -0700
                Re: Sugestions for runtime polymorphism Thiago Adams <thiago.adams@gmail.com> - 2016-09-30 11:18 -0700
                Re: Sugestions for runtime polymorphism BartC <bc@freeuk.com> - 2016-09-30 19:26 +0100
                Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-09-30 12:41 -0700
                Re: Sugestions for runtime polymorphism Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-30 21:07 +0100
                Re: Sugestions for runtime polymorphism Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-30 23:30 -0700
                Re: Sugestions for runtime polymorphism Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-10-01 11:35 +0100
                Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-10-01 14:44 -0700
        Re: Sugestions for runtime polymorphism Richard Heathfield <rjh@cpax.org.uk> - 2016-09-14 22:56 +0100
          Re: Sugestions for runtime polymorphism David Brown <david.brown@hesbynett.no> - 2016-09-15 13:19 +0200
            Re: Sugestions for runtime polymorphism James Kuyper <jameskuyper@verizon.net> - 2016-09-15 08:07 -0400
              Re: Sugestions for runtime polymorphism David Brown <david.brown@hesbynett.no> - 2016-09-15 14:24 +0200
                Re: Sugestions for runtime polymorphism Richard Heathfield <rjh@cpax.org.uk> - 2016-09-15 15:34 +0100
            Re: Sugestions for runtime polymorphism Thiago Adams <thiago.adams@gmail.com> - 2016-09-15 05:10 -0700
          Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-09-15 09:12 -0700
        Re: Sugestions for runtime polymorphism BartC <bc@freeuk.com> - 2016-09-14 23:32 +0100
        Re: Sugestions for runtime polymorphism "Chris M. Thomasson" <invalid@invalid.invalid> - 2016-09-14 17:35 -0700
        Re: Sugestions for runtime polymorphism Ian Collins <ian-news@hotmail.com> - 2016-09-15 16:24 +1200
          Re: Sugestions for runtime polymorphism Keith Thompson <kst-u@mib.org> - 2016-09-15 10:31 -0700
    Re: Sugestions for runtime polymorphism BartC <bc@freeuk.com> - 2016-09-14 22:53 +0100
      Re: Sugestions for runtime polymorphism Keith Thompson <kst-u@mib.org> - 2016-09-14 16:56 -0700
        Re: Sugestions for runtime polymorphism supercat@casperkitty.com - 2016-09-14 15:58 -0700
          Re: Sugestions for runtime polymorphism Keith Thompson <kst-u@mib.org> - 2016-09-14 18:49 -0700
  Re: Sugestions for runtime polymorphism luser droog <luser.droog@gmail.com> - 2016-09-14 14:17 -0700
    Re: Sugestions for runtime polymorphism Thiago Adams <thiago.adams@gmail.com> - 2016-09-14 14:25 -0700
      Re: Sugestions for runtime polymorphism luser droog <luser.droog@gmail.com> - 2016-09-14 14:40 -0700
      Re: Sugestions for runtime polymorphism luser droog <luser.droog@gmail.com> - 2016-09-14 14:57 -0700
      Re: Sugestions for runtime polymorphism BartC <bc@freeuk.com> - 2016-09-14 23:10 +0100
  Re: Sugestions for runtime polymorphism Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-15 11:23 -0700

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