Re: Definable operators

Craig Burley <burley@gnu.ai.mit.edu> writes amidst snipping and maiming:
> It's not clear to everyone what it means. Why wouldn't
> "1" + "2"
> evaluate to
> "3"
> for example?
>
> The concept of + always meaning the mathematical sense of addition is
> useful -- not just in the sense that "addition is useful", but that "+
> means _only_ addition" is useful in designing programming languages.
> In point of fact, "+ means _only_ addition" is _substantially_ more
> useful as a language feature than "+ means whatever the programmer
> wants it to mean".


How about "+" meaning the mathematical "+" defining a (semi?) group?
For "+" as string concatenation, that almost makes sense, although I
will admit that coming up with an inverse under "+" for string
concatenation is rather difficult.


Actually, under those constraints, the quasi-numerical implementation
of strings makes a lot of sense...


I don't know if I'm agreeing or disagreeing, here. But I think that
"+" denotes a behavior that "makes sense" only in relationship to
other behaviors applicable to a given type. I geuss I come in with a
little weaker constraint than Craig, but in basic agreement.


                happy hackin'


                david rush
                mailto:kumo@intercenter.net
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