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reformatting

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svn: r8114
This commit is contained in:
Eli Barzilay 2007-12-24 11:29:33 +00:00
parent 4923f00a0d
commit 9ba922ff1c
1 changed files with 47 additions and 52 deletions
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97
collects/scheme/promise.ss
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@ -33,15 +33,12 @@
;; single or multiple values
(fprintf port
(if write? "#<promise!~a~s" "#<promise!~a~a")
(if (null? (cdr p))
""
"(values ")
(if (null? (cdr p)) "" "(values ")
(car p))
(when (pair? (cdr p))
(let ([fmt (if write? " ~s" " ~a")])
(for-each (lambda (x) (fprintf port fmt x)) (cdr p))))
(unless (null? (cdr p))
(display ")" port))
(unless (null? (cdr p)) (display ")" port))
(display ">" port)]
[(promise? p) (loop (promise-val p))] ; hide sharing
[else (loop (list p))])))
@ -89,52 +86,50 @@
(define handle-results
(case-lambda
[(single) (values #t single)]
[multi (values #f multi)]))
[(single) (values #t single)]
[multi (values #f multi)]))
(define (force promise)
(if (promise? promise)
(let loop ([p (promise-val promise)])
(cond
[(procedure? p)
;; mark root for cycle detection:
(set-promise-val! promise running)
(with-handlers* ([void (lambda (e)
(set-promise-val! promise (lambda () (raise e)))
(raise e))])
(let-values ([(single? vals*)
(call-with-values p
handle-results)])
(if single?
(let loop1 ([val* vals*])
(if (promise? val*)
(let loop2 ([promise* val*])
(let ([p* (promise-val promise*)])
(set-promise-val! promise* promise) ; share with root
(cond [(procedure? p*)
(let-values ([(single? vals)
(call-with-values p*
handle-results)])
(if single?
(loop1 vals)
(begin
(set-promise-val! promise vals)
(apply values vals))))]
[(or (pair? p*) (null? p*))
(set-promise-val! promise p*)
(apply values p*)]
[(promise? p*) (loop2 p*)]
[else p*])))
(begin ; error here for "library approach" (see above URL)
(if (or (null? val*) (pair? val*) (procedure? val*))
(set-promise-val! promise (list val*))
(set-promise-val! promise val*))
val*)))
(begin ; error here for "library approach" (see above URL)
(set-promise-val! promise vals*)
(apply values vals*)))))]
[(or (pair? p) (null? p)) (apply values p)]
[(promise? p) (loop (promise-val p))]
[else p]))
;; different from srfi-45: identity for non-promises
promise))
(let loop ([p (promise-val promise)])
(cond
[(procedure? p)
;; mark root for cycle detection:
(set-promise-val! promise running)
(with-handlers* ([void (lambda (e)
(set-promise-val! promise
(lambda () (raise e)))
(raise e))])
(let-values ([(single? vals*) (call-with-values p handle-results)])
(if single?
(let loop1 ([val* vals*])
(if (promise? val*)
(let loop2 ([promise* val*])
(let ([p* (promise-val promise*)])
(set-promise-val! promise* promise) ; share with root
(cond [(procedure? p*)
(let-values ([(single? vals)
(call-with-values
p* handle-results)])
(if single?
(loop1 vals)
(begin (set-promise-val! promise vals)
(apply values vals))))]
[(or (pair? p*) (null? p*))
(set-promise-val! promise p*)
(apply values p*)]
[(promise? p*) (loop2 p*)]
[else p*])))
(begin ; error here for "library approach" (see above URL)
(if (or (null? val*) (pair? val*) (procedure? val*))
(set-promise-val! promise (list val*))
(set-promise-val! promise val*))
val*)))
(begin ; error here for "library approach" (see above URL)
(set-promise-val! promise vals*)
(apply values vals*)))))]
[(or (pair? p) (null? p)) (apply values p)]
[(promise? p) (loop (promise-val p))]
[else p]))
;; different from srfi-45: identity for non-promises
promise))