5 minutes ago, David Van Horn wrote:
> On 2/15/11 7:02 AM, Eli Barzilay wrote:
> > Three hours ago, Hendrik Boom wrote:
> >> On Mon, Feb 14, 2011 at 04:43:24PM -0600, Robby Findler wrote:
> >>> I guess I'm asking if true is bound somewhere or not.
> >>
> >> It almost looks as if you want predicates on the right side of =>'
> >
> > Yes -- the whole point of the simple arrow-less version is to make
> > using predicates very easy. For example, instead of some
> >
> > 1. (test E1 =satisfies> even?
> > E2 =satisfies> (lambda (x) (> x 50)))
> >
> > you'd write
> >
> > 2. (test (even? E1)
> > (> E2 50))
>
> You could allow the arrow-less form (which I like) but require it to
> produce #t and only #t. This accommodates your examples while catching
> things like:
>
> (test (fact 5) 121)
Nice idea -- and for the rare cases where you want a non-boolean
predicate you'd resort to the less conveniet
(test (and (member E '(1 2 3)) #t))
Robby: would you find this acceptable, or is the hole that it leaves
(making the no-arrow mistake with a #t-resulting expression) too big?
--
((lambda (x) (x x)) (lambda (x) (x x))) Eli Barzilay:
http://barzilay.org/ Maze is Life!
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