No, you cannot define predicates for function types. If you explain the problem you have, we might be able to explain another solution that will work.
On Mon, May 20, 2013 at 1:32 AM, Paul Leger <[email protected]> wrote: > Hi all, > Maybe, this question is very easy. In the following code, I try > defining a predicate for T2, but I cannot because T1 it is a function. > > (define-type T1 (Symbol -> Any) ) > (define-type T2 (U Symbol Number T1)) > > ;(define-predicate T1? Procedure) ;this line is useless > > (define-predicate T2? T2) > >> Type Checker: Type T2 could not be converted to a contract. in: T2 > > My unsuccessful answer is: > (define-type T2 (U Symbol Number Procedure)) > > I do not like it because I lose the relationship between T1 and T2. Are > there some possibility > > Thank in advance, > Paul > > ____________________ > Racket Users list: > http://lists.racket-lang.org/users > ____________________ Racket Users list: http://lists.racket-lang.org/users
