On 02/01/2012 10:10 AM, Ryan Culpepper wrote:
On 02/01/2012 09:55 AM, ntoro...@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.
1
2
3
Fascinating!
Thanks for checking over my stuff. I'll get rid of it shortly.
Neil T
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