Added code to demonstrate problem of using call/cc within a global definition

This commit is contained in:
Justin Ethier 2015-03-22 09:11:03 -04:00
parent 89526d79e8
commit 28d8c89a71
2 changed files with 69 additions and 49 deletions

View file

@ -11,17 +11,25 @@
;; TODO: define repl iteration, and wrap in an exception handler
; TODO: the below is broken because CPS conversion replaces it with:
;
; ((lambda (call/cc)
; (define repl:next-line
;
; So repl:next-line is never defined as a global!
; We need a better solution
(define (repl:next-line)
; (call/cc
; (lambda (continue)
(write '1)
(call/cc
(lambda (k)
(with-exception-handler
(lambda (obj)
(write (list 'an-error-occurred obj))
); (continue #t))
(k #t))
(lambda ()
(repl)))) ;)
; (repl:next-line))
;#f)
(repl)))))
(repl:next-line))
(define (repl)
(display "cyclone> ")

View file

@ -23,49 +23,61 @@
;(eval '(a 1))
;(eval '(begin (define (a z) z) (a 1) (a 1)))
(write
(with-exception-handler
(lambda (con)
(cond
((string? con)
(display con))
(else
(display "a warning has been issued")))
42)
(lambda ()
(+ (raise-continuable "should be a number") 23)
)))
;prints: should be a number
;=> 65
(write
; TODO: demonstrates problem of using call/cc within a global.
; all globals are created with a k parameter, EG:
; ((lambda (call/cc)
; (define test
; (lambda (k$104)
;
; Need to rewrite the code to use this, and preserve the global def
(define (test)
(call/cc
(lambda (k)
(with-exception-handler
(lambda (x)
(display "condition: ")
(write x)
;(newline)
(k 'exception))
(lambda ()
(+ 1 (raise 'an-error)))))))
(k #t))))
(write (test))
(with-exception-handler
(lambda (x)
(display "something went wrong\n"))
(lambda ()
(+ 1 (raise 'an-error))))
(define test '(a b))
(set-car! test '(1 2 3))
(write test)
(raise 'done)
(define (loop n)
(cond
((= n 10000)
(write test)
(loop 0))
(else
(loop (+ n 1)))))
(loop 0)
;(write
; (with-exception-handler
; (lambda (con)
; (cond
; ((string? con)
; (display con))
; (else
; (display "a warning has been issued")))
; 42)
; (lambda ()
; (+ (raise-continuable "should be a number") 23)
; )))
;;prints: should be a number
;;=> 65
;
;(write
; (call/cc
; (lambda (k)
; (with-exception-handler
; (lambda (x)
; (display "condition: ")
; (write x)
; ;(newline)
; (k 'exception))
; (lambda ()
; (+ 1 (raise 'an-error)))))))
;
;(with-exception-handler
; (lambda (x)
; (display "something went wrong\n"))
; (lambda ()
; (+ 1 (raise 'an-error))))
;
;(define test '(a b))
;(set-car! test '(1 2 3))
;(write test)
;(raise 'done)
;(define (loop n)
; (cond
; ((= n 10000)
; (write test)
; (loop 0))
; (else
; (loop (+ n 1)))))
;(loop 0)