str % vals -like idea but for statements

[Erik Max Francis]

Michael Hudson wrote:

> Erik Max Francis <max at alcyone.com> writes:
> 
> > Andrew Koenig wrote:
> >
[attribution lost here]
> > > > It's not.  It's (T, T) -> T!
> > >
> > > It's (T1, T2) -> union(T1, T2)
> >
> > If we want to be completely anal, shouldn't it be
> >
> >       T1 x T2 -> T1 U T2
> >
> > where x is the Cartesian product and U is the set union operator? 
> > :-)
> >
> > Your left hand side there is just an ordered pair of sets, rather
> > than a
> > set of ordered pairs :-).
> 
> You could make it T x T -> T if you meant T in the common lisp sense
> of "all types" -- which probably makes most sense.

If you'll look back through the attributions, Andrew was already
clarifying that distinction (it's not T x T -> T, since the resultant
type cannot be _any_ type, but can only be one of the two types that was
involved on the left hand side of the mapping.

-- 
 Erik Max Francis / max at alcyone.com / http://www.alcyone.com/max/
 __ San Jose, CA, USA / 37 20 N 121 53 W / &tSftDotIotE
/  \ Sentimentality is a superstructure covering brutality.
\__/ C.G. Jung
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