Re: Sugestions for runtime polymorphism

From	BartC <bc@freeuk.com>
Newsgroups	comp.lang.c
Subject	Re: Sugestions for runtime polymorphism
Date	2016-09-22 13:16 +0100
Organization	A noiseless patient Spider
Message-ID	<ns0i2u$nb8$1@dont-email.me> (permalink)
References	(15 earlier) <e06bdc46-44cb-418e-8783-94c3147871f3@googlegroups.com> <8e6459ac-a363-487b-96d8-3585fad04dd5@googlegroups.com> <7ee4b7c9-5d16-40bf-acb0-738ae7e3bc86@googlegroups.com> <9179e698-fe07-416c-a885-cca3f6b5d606@googlegroups.com> <kfn8tukfhmp.fsf@x-alumni2.alumni.caltech.edu>

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On 22/09/2016 09:44, Tim Rentsch wrote:
> Thiago Adams <thiago.adams@gmail.com> writes:
>
>> [accomplishing type changing using a 'union' pattern]

>     /* These functions provide type conversion */
>     static inline Foo as_Foo( Object it ){ return (Foo)it; }
>     static inline Bas as_Bas( Object it ){ return (Bas)it; }

> Taking an approach along these lines gets rid of any need to use
> unions, and the behavior it relies on is blessed by the Standard.

So you've got rid of unions by using casts everywhere instead 
(presumably as being the lesser 'evil').

But unions result in less intrusion within the code.

(Also, depending on the actual arrangement, they can make it easier to 
share common fields other than just .type.)

-- 
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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