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add some convenience to the enumerators and change call-with-values

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into define-values
This commit is contained in:
Robby Findler 2014-03-20 22:16:48 -05:00
parent 23fa168309
commit c11de94f2a
1 changed files with 20 additions and 20 deletions
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40
pkgs/redex-pkgs/redex-lib/redex/private/enumerator.rkt
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@ -20,6 +20,7 @@
empty/e
const/e
from-list/e
fin/e
disj-sum/e
disj-append/e
cons/e
@ -199,6 +200,8 @@
(λ (x)
(hash-ref rev-map x)))))
(define (fin/e . args) (from-list/e (remove-duplicates args)))
(define nats/e
(enum +inf.0
identity
@ -554,12 +557,9 @@
[(not (infinite? (size e)))
(enum +inf.0
(λ (n)
(call-with-values
(λ ()
(quotient/remainder n (size e)))
(λ (q r)
(cons (decode e r)
(decode (f (decode e r)) q)))))
(define-values (q r) (quotient/remainder n (size e)))
(cons (decode e r)
(decode (f (decode e r)) q)))
(λ (ab)
(+ (* (size e) (encode (f (car ab)) (cdr ab)))
(encode e (car ab)))))]
@ -679,12 +679,9 @@
[(not (infinite? (size e)))
(enum +inf.0
(λ (n)
(call-with-values
(λ ()
(quotient/remainder n (size e)))
(λ (q r)
(cons (decode e r)
(decode (f (decode e r)) q)))))
(define-values (q r) (quotient/remainder n (size e)))
(cons (decode e r)
(decode (f (decode e r)) q)))
(λ (ab)
(+ (* (size e) (encode (f (car ab)) (cdr ab)))
(encode e (car ab)))))]
@ -769,14 +766,17 @@
(λ (x)
(encode (force promise/e) x))))
;; fix/e : size (enum a -> enum a) -> enum a
(define (fix/e size f/e)
(define self (delay (f/e (fix/e size f/e))))
(enum size
(λ (n)
(decode (force self) n))
(λ (x)
(encode (force self) x))))
;; fix/e : [size] (enum a -> enum a) -> enum a
(define fix/e
(case-lambda
[(f/e) (fix/e +inf.0 f/e)]
[(size f/e)
(define self (delay (f/e (fix/e size f/e))))
(enum size
(λ (n)
(decode (force self) n))
(λ (x)
(encode (force self) x)))]))
;; many/e : enum a -> enum (listof a)
;; or : enum a, #:length natural -> enum (listof a)