Re: [q-lang-users] Special values or failing functions

[John C. <co...@cc...>]

Albert Graef scripsit:

> As you point out, it would be nice to have a 'fail' which not only fails
> the current equation, but *all* equations for the current redex. That's
> an interesting idea, because it doesn't interfere as much with the
> rewriting semantics as the catch/throw exception handling which Q
> already offers as a means to exit a function anywhere. Shame on me that
> I didn't think about this before! ;-) I'm tempted to actually implement
> this as an experimental feature. What does everybody else think about
> this? How should we name this operation?

Presumably "const bottom;" somewhere in the standard library is enough?
I like the name "bottom".

> In this special case it would make sense to use 'inf' (defined in
> math.q) as a sentinel value for non-existing links. 

IMHO it's better to use "nan" than "inf" in the numeric case.  It has
exactly the right semantics.

-- 
Work hard,                                      John Cowan
play hard,                                      co...@cc...
die young,                                      http://www.ccil.org/~cowan
rot quickly.