Add contract for seen parameter.

This commit is contained in:
Sam Tobin-Hochstadt 2013-05-08 15:09:13 -04:00
parent a07cdf39ff
commit da3f8f8ec0

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@ -1,8 +1,9 @@
#lang racket/base
(require "../utils/utils.rkt")
(require (rep type-rep))
(require (rep type-rep) (contract-req))
(provide (all-defined-out))
(provide (except-out (all-defined-out) current-seen))
(provide/cond-contract [current-seen (parameter/c list?)])
(define current-seen (make-parameter null))
(define (currently-subtyping?) (not (null? (current-seen))))