[racket-dev] [plt] Push #24227: master branch updated

On 02/01/2012 09:55 AM, ntoronto at racket-lang.org wrote:
> collects/unstable/contract.rkt
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> --- OLD/collects/unstable/contract.rkt
> +++ NEW/collects/unstable/contract.rkt
> @@ -171,6 +171,14 @@
>                    (lambda (idx . elems) #t)))))))
>        sequence?)))
>
> +;; Added by ntoronto
> +
> +(define contract/c (or/c contract? (any/c . ->  . any/c)))
> +
> +(define (treeof elem-contract)
> +  (or/c elem-contract
> +        (listof (recursive-contract (treeof elem-contract) #:flat))))

'contract/c' is not useful: 'contract?' already recognizes predicates, 
and due to the way 'or/c' handles mixed flat and higher-order contracts, 
the arrow contract's checks *never apply*.

 > (contract? even?)
#t

 > (define/contract ev (or/c contract? (-> any/c any/c)) even?)
 > (ev 5 6 7) ;; You might think this would be a contract error... nope!
even?: expects 1 argument, given 3: 5 6 7

 > (define/contract vv (or/c contract? (-> any/c any/c)) vector->values)
 > (vv '#(1 2 3)) ;; Likewise... but not a contract error.
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Ryan