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Re: language design after Algol 60, was Add nested-function support

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On Thu, 12 Apr 2018 01:09:42 +0200, Hans-Peter Diettrich
<DrDiettrich1@netscape.net> wrote:

>Am 10.04.2018 um 20:32 schrieb George Neuner:
>> On Tue, 10 Apr 2018 05:48:43 GMT, anton@mips.complang.tuwien.ac.at
>> (Anton Ertl) wrote:
>
>> Smalltalk had/has single inheritence only, and it's dynamic dispatch
>> mechanism is very different from that of C++.
>
>Isn't *multiple inheritance* one of the features that C++ proved
>impractical? Which other languages support multiple inheritance?

No.  It proved only that C++ wasn't able to accomodate conflicting
classes effectively.  Lisp handles this same problem much more
effectively, so it isn't a generic fault of MI.

Moreover, most (all?) SI languages implement interfaces (abstract
classes).  Interfaces mainly are a workaround for lacking real MI, so
why would they do that if it were useless?


C++ implemented interfaces also, but it did so because it's object
layout semantics did not allow for the merging of non-conflicting
members, and its dispatch semantics did not adequately address
predictable function dispatch in the case of "diamond" inheritance.

Lisp addresses both of these issues very well, and also handles the
issue of conflicting (by type) members.


>[Lots of languages have multiple inheritance.  Python is one of the
>more popular these days.  As you've seen, opinions vary about how
>useful it is.  -John]

Obviously it depends on the specifics of the hierarchy. There is no
guarantee that MI will save you anything.  But where interfaces are
commonly employed in SI languages, an implementation under MI might
well be less work.

It often is the case that a subclass has to reimplement something from
one of its ancestors, and it *might* be the case with MI that there is
a clash wrt handling something that has to be worked around.  But
using interfaces, it is *guaranteed* that you will have to
(re)implement not just things that conflict, but everything in the
interface.

YMMV,
George

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Re: Add nested-function support in a language the based on a stack-machine Martin Ward <martin@gkc.org.uk> - 2018-03-12 16:17 +0000
  Re: Add nested-function support in a language the based on a stack-machine Kaz Kylheku <157-073-9834@kylheku.com> - 2018-03-13 03:02 +0000
    Re: Add nested-function support in a language the based on a stack-machine Martin Ward <martin@gkc.org.uk> - 2018-03-19 11:04 +0000
      Re: Add nested-function support in a language the based on a stack-machine Gene Wirchenko <genew@telus.net> - 2018-03-19 12:50 -0700
        Re: Add nested-function support in a language the based on a stack-machine Kaz Kylheku <157-073-9834@kylheku.com> - 2018-03-20 16:16 +0000
        Re: Add nested-function support in a language the based on a stack-machine Martin Ward <martin@gkc.org.uk> - 2018-03-23 10:44 +0000
          Re: algorithm performance, was Add nested-function support in a language the based on a stack-machine Andy Walker <anw@cuboid.co.uk> - 2018-03-23 18:47 +0000
            Re: algorithm performance, was Add nested-function support in a language the based on a stack-machine anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2018-03-24 14:06 +0000
              Re: algorithm performance, was Add nested-function support in a language the based on a stack-machine rpw3@rpw3.org (Rob Warnock) - 2018-03-25 07:02 +0000
                Re: algorithm performance "Robin Vowels" <robin51@dodo.com.au> - 2018-03-27 01:22 +1100
          Re: sorting performance, Add nested-function support in a language the based on a stack-machine w.clodius@icloud.com (William Clodius) - 2018-03-24 23:25 -0600
      Re: Add nested-function support in a language the based on a stack-machine anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2018-03-20 09:06 +0000
        Re: Add nested-function support in a language the based on a stack-machine Bill Findlay <findlaybill@blueyonder.co.uk> - 2018-03-20 12:49 +0000
        Re: language design after Algol 60, was Add nested-function support Martin Ward <martin@gkc.org.uk> - 2018-03-27 14:46 +0100
          Re: language design after Algol 60, was Add nested-function support anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2018-03-30 14:20 +0000
          Re: language design after Algol 60, was Add nested-function support Martin Ward <martin@gkc.org.uk> - 2018-04-06 16:09 +0100
            Re: language design after Algol 60, was Add nested-function support "Derek M. Jones" <derek@_NOSPAM_knosof.co.uk> - 2018-04-08 14:21 +0100
              Re: language design after Algol 60, was Add nested-function support George Neuner <gneuner2@comcast.net> - 2018-04-09 16:51 -0400
                Re: language design after Algol 60, was Add nested-function support anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2018-04-10 05:48 +0000
                Re: language design after Algol 60, was Add nested-function support George Neuner <gneuner2@comcast.net> - 2018-04-10 14:32 -0400
                Re: language design after Algol 60, was Add nested-function support Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2018-04-12 01:09 +0200
                Re: language design after Algol 60, was Add nested-function support bartc <bc@freeuk.com> - 2018-04-12 11:51 +0100
                Re: language design after Algol 60, was Add nested-function support bartc <bc@freeuk.com> - 2018-04-12 19:40 +0100
                Re: language design after Algol 60, was Add nested-function support Martin Ward <martin@gkc.org.uk> - 2018-04-13 14:10 +0100
                Re: language design after Algol 60 "Robin Vowels" <robin51@dodo.com.au> - 2018-04-14 14:11 +1000
                RE: language design after Algol 60 "Costello, Roger L." <costello@mitre.org> - 2018-04-16 12:56 +0000
                Re: language design after Algol 60 "Robin Vowels" <robin51@dodo.com.au> - 2018-04-17 19:08 +1000
                Re: Language design after Algol 60 "Robin Vowels" <robin51@dodo.com.au> - 2018-04-18 14:58 +1000
                Re: language design after Algol 60 Gene Wirchenko <genew@telus.net> - 2018-04-18 16:12 -0700
                Re: language design after Algol 60 Martin Ward <martin@gkc.org.uk> - 2018-05-01 10:42 +0100
                Re: language design after Algol 60 "Robin Vowels" <robin51@dodo.com.au> - 2018-04-14 14:19 +1000
                Re: language design after Algol 60 bartc <bc@freeuk.com> - 2018-04-14 20:43 +0100
                Re: language design after Algol 60 Andy Walker <anw@cuboid.co.uk> - 2018-04-15 00:04 +0100
                Re: language design after Algol 60, was Add nested-function support rpw3@rpw3.org (Rob Warnock) - 2018-04-12 14:05 +0000
                Re: language design after Algol 60, was Add nested-function support George Neuner <gneuner2@comcast.net> - 2018-04-12 20:51 -0400
                Re: OOP language design after Algol 60, was Add nested-function support Kaz Kylheku <157-073-9834@kylheku.com> - 2018-04-13 03:22 +0000
                Re: OOP language design after Algol 60, was Add nested-function support Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2018-04-13 10:22 +0200
                Re: OOP language design after Algol 60, was Add nested-function support George Neuner <gneuner2@comcast.net> - 2018-04-14 13:40 -0400
                Re: OOP language design after Algol 60, was Add nested-function support Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2018-04-15 00:12 +0200
                Re: OOP language design after Algol 60, was Add nested-function support Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2018-04-15 00:23 +0200
                Re: language design after Algol 60, was Add nested-function support "Derek M. Jones" <derek@_NOSPAM_knosof.co.uk> - 2018-04-10 13:15 +0100
                Re: language design after Algol 60, was Add nested-function support Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2018-04-11 13:27 +0200
                Re: language design after Algol 60, was Add nested-function support "Derek M. Jones" <derek@_NOSPAM_knosof.co.uk> - 2018-04-11 20:06 +0100
                Re: language design after Algol 60, was Add nested-function support Kaz Kylheku <157-073-9834@kylheku.com> - 2018-04-10 18:32 +0000
                Re: language design after Algol 60, was Add nested-function support George Neuner <gneuner2@comcast.net> - 2018-04-12 20:57 -0400
                Re: OOP language design after Algol 60, was Add nested-function support Kaz Kylheku <157-073-9834@kylheku.com> - 2018-04-13 03:28 +0000
            Re: language design after Algol 60, was Add nested-function support albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2018-05-05 13:50 +0200
      Re: Add nested-function support in a language the based on a stack-machine mac <acolvin@efunct.com> - 2018-03-20 15:27 +0000
  Re: Add nested-function support in a language the based on a stack-machine w.clodius@icloud.com (William Clodius) - 2018-03-12 21:09 -0600
    Re: Add nested-function support in a language the based on a stack-machine Kartik Agaram <ak@akkartik.com> - 2018-03-13 13:27 -0700
      Re: Add nested-function support in a language the based on a stack-machine Kaz Kylheku <157-073-9834@kylheku.com> - 2018-03-14 00:07 +0000
        Re: Add nested-function support in a language the based on a stack-machine Kartik Agaram <ak@akkartik.com> - 2018-03-13 22:31 -0700
          Re: Add nested-function support in a language the based on a stack-machine Kaz Kylheku <157-073-9834@kylheku.com> - 2018-03-14 14:49 +0000
    Re: Add nested-function support in a language the based on a stack-machine Kaz Kylheku <157-073-9834@kylheku.com> - 2018-03-13 20:51 +0000
    Re: Add nested-function support in a language the based on a stack-machine Andy Walker <anw@cuboid.co.uk> - 2018-03-14 00:27 +0000
      Re: Add nested-function support in a language the based on a stack-machine Andy Walker <anw@cuboid.co.uk> - 2018-03-14 16:37 +0000
  Re: Add nested-function support in a language the based on a stack-machine anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2018-03-14 15:16 +0000

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