suzanne.soy/racket
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just checking it in

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svn: r4426
This commit is contained in:
John Clements 2006-09-23 11:21:17 +00:00
parent 02d9fbd35c
commit fc7322a4b3
1 changed files with 21 additions and 9 deletions
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30
collects/lazy/lazy.ss
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@ -43,13 +43,15 @@
;; --------------------------------------------------------------------------
;; Delay/force etc
(provide ~)
(defsubst (~ x) (delay x))
(define (! x) (if (promise? x) (! (force x)) x))
;; the exposed `!' must be a special form
(provide (rename special-form-! !))
;; hack to see if it solves a certificate problem:
(provide (rename ! crazythingthatwillneverbereferredto))
(defsubst (special-form-! x) (! x) special-form-! !)
;; These things are useful too, to write strict functions (with various
@ -256,18 +258,26 @@
;; `!apply': provided as `apply' (no need to provide `~!apply', since all
;; function calls are delayed by `#%app')
(define-syntax (jbc! stx)
(syntax-case stx (!)
[(_ arg) (syntax-property #`(! arg) 'stepper-skipto '(syntax-e cdr syntax-e cdr car))]))
(define-syntax (!*app stx)
(syntax-case stx (~ ! !! !list !!list !values !!values)
[(_ f x ...)
(let ([$$ (lambda (stx) (syntax-property stx 'stepper-skipto '(syntax-e cdr cdr both-l () (car))))]
[$ (lambda (stx) (syntax-property stx 'stepper-skipto '(syntax-e cdr syntax-e car)))])
(with-syntax ([(y ...) (generate-temporaries #'(x ...))])
(with-syntax ([(!y ...) (map (lambda (stx) (syntax-property stx 'stepper-skipto '(syntax-e cdr syntax-e cdr car)))
(syntax->list #`((! y) ...)))])
;; use syntax/loc for better errors etc
(with-syntax ([lazy (syntax/loc stx (p y ...))]
[strict (syntax/loc stx (p (! y) ...))])
(syntax/loc stx
(let ([p f] [y x] ...)
(if (lazy? p) lazy strict)))))]))
(with-syntax ([lazy (quasisyntax/loc stx (p y ...))]
[strict (quasisyntax/loc stx (p !y ...))])
(quasisyntax/loc stx
(let ([p f] [y x] ...)
#,($$ #`(if (lazy? p) lazy strict))))))))]))
(defsubst (!app f x ...) (!*app (! f) x ...))
(defsubst (!app f x ...) (!*app (jbc! f) x ...))
(defsubst (~!*app f x ...) (~ (!*app f x ...)))
(defsubst (~!app f x ...) (~ (!app f x ...)))
@ -768,8 +778,10 @@
;; --------------------------------------------------------------------------
;; Initialize special evaluation hooks
(let ([prim-eval (current-eval)])
(current-eval (lambda (expr) (!! (prim-eval expr)))))
;; taking this out so that stepper test cases will work correctly:
#;(let ([prim-eval (current-eval)])
(current-eval (lambda (expr) (!! (prim-eval expr)))))
)