Subj : Re: anyone know of a language where nonexistent functions return no
To   : comp.programming
From : Chris Dams
Date : Fri Jul 22 2005 02:14 pm

Dear Pantagruel,

On Fri, 2005-07-22 at 04:05 -0700, pantagruel wrote:

> nope, you did not misunderstand.
> yes it does create a debugging nightmare in most situations, I am
> wondering if any studies have ever been done in specific domains where
> this was proposed as being useful. The reason is that I have a
> situation defined where it is useful and am writing up my findings but
> as I have never encountered anything similar in the literature I feel
> sort of weirded out about the claims I feel forced to make about the
> usefulness in my context.

Maybe this goes a bit in the direction that you are looking for:
The Coq system for automatic theorem proving is also a programming
language where one can simple claim that f is a function on the natural
numbers by saying "Parameter f:nat->nat." After that one can have f in
expressions and it simply remains unevaluated unless more information
about f is supplied. This is similar to the situation in computer
algebra programs.

Best wishes,
Chris

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