I'm not sure what you mean by the typed version of case. The version of case in TR is the same as the one in untyped racket, so we cannot change it to only require an identifier. The real solution is to fix PR 14502, and while it is non-trivial (> 1 hour of work) we mostly know what needs to be done to fix it.
On Sun, May 11, 2014 at 5:54 PM, Alexander D. Knauth <alexan...@knauth.org> wrote: > > On May 11, 2014, at 7:41 PM, Eric Dobson <eric.n.dob...@gmail.com> wrote: > > The issue is that there is a temporary variable that has the same > value as x and TR cannot see that they point to the same location. > Your implementation of case/type has the same problem. I thought there > was a bug filed for it but couldn't find it so just filed one. > http://bugs.racket-lang.org/query/?cmd=view&pr=14502 > > > Use this: > #lang typed/racket > (require typed/rackunit) > > (define-syntax-rule > (case/type y x-expr > [t1 body ...] ...) > (let ([y x-expr]) > (cond [((make-predicate t1) y) body ...] ...)) > ) > > This worked: > #lang typed/racket > (require typed/rackunit) > (require syntax/parse/define) > > (define-simple-macro > (case/type x:id > [t:expr body:expr ...+] ...) > (cond [((make-predicate t) x) body ...] ...) > ) > > (define (my-length x) > (case/type x > [String (string-length x)] > [(Listof Any) ((inst length Any) x)] > ;[VectorTop (vector-length x)] > )) > (check-equal? (my-length "12345") 5) > (check-equal? (my-length '(1 2 3 4 5)) 5) > ;(check-equal? (my-length #(1 2 3 4 5)) 5) > > Would something like that work for the typed version of case? > ____________________ Racket Users list: http://lists.racket-lang.org/users
