134 lines
3.6 KiB
Scheme
134 lines
3.6 KiB
Scheme
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(library (ikarus trace)
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(export make-traced-procedure trace-symbol! untrace-symbol!)
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(import (ikarus))
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(define k* '())
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(define display-prefix
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(lambda (ls t)
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(unless (null? ls)
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(display (if t "|" " "))
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(display-prefix (cdr ls) (not t)))))
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(define display-trace
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(lambda (k* v)
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(display-prefix k* #t)
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(write v)
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(newline)))
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(define make-traced-procedure
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(lambda (name proc)
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(lambda args
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(call/cf
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(lambda (f)
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(cond
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[(memq f k*) =>
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(lambda (ls)
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(display-trace ls (cons name args))
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(apply proc args))]
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[else
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(display-trace (cons 1 k*) (cons name args))
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(dynamic-wind
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(lambda () (set! k* (cons f k*)))
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(lambda ()
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(call-with-values
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(lambda ()
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(call/cf
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(lambda (nf)
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(set! f nf)
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(set-car! k* nf)
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(apply proc args))))
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(lambda v*
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(display-prefix k* #t)
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(unless (null? v*)
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(write (car v*))
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(let f ([v* (cdr v*)])
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(cond
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[(null? v*) (newline)]
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[else
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(write-char #\space)
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(write (car v*))
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(f (cdr v*))])))
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(apply values v*))))
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(lambda () (set! k* (cdr k*))))]))))))
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(define traced-symbols '())
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(define trace-symbol!
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(lambda (s)
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(cond
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[(assq s traced-symbols) =>
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(lambda (pr)
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(let ([a (cdr pr)] [v (symbol-value s)])
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(unless (eq? (cdr a) v)
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(unless (procedure? v)
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(error 'trace
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"the top-level value of ~s is ~s (not a procedure)"
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s v))
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(let ([p (make-traced-procedure s v)])
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(set-car! a v)
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(set-cdr! a p)
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(set-symbol-value! s p)))))]
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[else
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(unless (symbol-bound? s)
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(error 'trace "~s is unbound" s))
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(let ([v (symbol-value s)])
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(unless (procedure? v)
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(error 'trace "the top-level value of ~s is ~s (not a procedure)"
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s v))
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(let ([p (make-traced-procedure s v)])
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(set! traced-symbols
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(cons (cons s (cons v p)) traced-symbols))
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(set-symbol-value! s p)))])))
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(define untrace-symbol!
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(lambda (s)
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(define loop
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(lambda (ls)
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(cond
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[(null? ls) '()]
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[(eq? s (caar ls))
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(let ([a (cdar ls)])
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(when (eq? (cdr a) (symbol-value s))
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(set-symbol-value! s (car a)))
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(cdr ls))]
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[else (cons (car ls) (loop (cdr ls)))])))
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(set! traced-symbols (loop traced-symbols))))
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)
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#!eof
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Try:
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(trace-define fact
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(lambda (n)
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(if (zero? n)
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1
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(* n (fact (sub1 n))))))
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(fact 5)
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(trace-define (fact n m)
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(cond
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[(zero? n) m]
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[else (fact (sub1 n) (* n m))]))
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(fact 5 1)
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(trace-define (fact n m k)
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(cond
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[(zero? n) (k m)]
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[else (begin (fact (sub1 n) (* n m) k) 0)]))
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(call/cc
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(lambda (k)
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(fact 6 1
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(trace-lambda escape (v) (k v)))))
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(trace-define (infinite-loop n)
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(infinite-loop (add1 n)))
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(infinite-loop 0)
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