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From: sjs@spectral.ctt.bellcore.com (Stan Switzer)
Newsgroups: comp.lang.c++,comp.object
Subject: Re: Inheritance vs. Composition
Message-ID: <20020@bellcore.bellcore.com>
Date: 15 Feb 90 16:39:58 GMT
References: <PCG.90Feb13153607@rupert.cs.aber.ac.uk> <12029@goofy.megatest.UUCP>
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Reply-To: sjs@bellcore.com Switzer)
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Dave Jones (djones@megatest.UUCP) writes:
> From article <PCG.90Feb13153607@rupert.cs.aber.ac.uk>,
>    by pcg@rupert.cs.aber.ac.uk (Piercarlo Grandi):
> 
> > ... [ to ] map the concepts ultimately onto contiguity or
> > pointers (the only ways we have in a computer to indicate a
> > relationship between data).
> 
> That's what this all comes down to isn't it? That and what kind of
> shorthand-resolution you want the compiler to do for you. (Not easy
> questions, actually.)

I was meaning to comment on this earlier, but I let it pass.  There
are many ways to represent relationships in a computer.  For instance,
relational databases (conceptually) use an associative technique based
on the equality of attribute values.  Another associative technique is
pattern matching (grep, and X resource databases).  Other types of
reference relationships might include inter-addressing-environment
references, file references, and persistent-object store references.

Even granting the importance of contiguous values and pointer
references, there are all sorts of possible pointer semantics: "Atom"
semantics (eq <=> equal -- SETL, or some dialect of SETL, did this),
capability references, self-describing references, context-described
references, and simple storage-indexing memory references.

> When I get into a discussion of this stuff, and inevitably somebody
> says something like, 'But that can all be solved with post-recurrent
> semideclined prevaricated polytrophism,' I say, 'Mumble, ... refresh
> my memory on what that means. What do the compiler's lookup-tables do,
> and when do you use pointers at runtime?'

Sure, there is a lot of terminology out there, some of it needlessly
complicated, but this terminology _does_ attempt to make useful
distinctions.

> For the last few years, just for the fun of it, I've been dreaming up my
> own sequential imperative language.

What!  Another one?

Stan Switzer  sjs@bellcore.com