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;;; -*-Scheme-*-
;;;
;;; A simple debugger (needs much work)
(define (backtrace . args)
(if (> (length args) 1)
(error 'backtrace "too many arguments"))
(if (not (null? args))
(if (not (eq? (type (car args)) 'control-point))
(error 'backtrace "argument must be a control point")))
(let ((trace
(apply backtrace-list args))
(maxlen 28))
(if (null? args)
(set! trace (cdddr trace)))
(for-each
(lambda (frame)
(let* ((func
(format #f "~s" (vector-ref frame 0)))
(indent
(- maxlen (string-length func))))
(display func)
(if (negative? indent)
(begin
(newline)
(set! indent maxlen)))
(do ((i indent (1- i)))
((> 0 i))
(display " ")))
(fluid-let
((print-depth 2)
(print-length 3))
(display (vector-ref frame 1)))
(newline))
trace))
#v)
(define (show env)
(fluid-let
((print-length 2)
(print-depth 2))
(do ((f (environment->list env) (cdr f)))
((null? f))
(do ((b (car f) (cdr b)))
((null? b))
(format #t "~s\t~s~%" (caar b) (cdar b)))
(print '-------)))
#v)
(define inspect)
(let ((frame)
(trace)
(help-text
'("q -- quit inspector"
"f -- print current frame"
"u -- go up one frame"
"d -- go down one frame"
"^ -- go to top frame"
"$ -- go to bottom frame"
"e -- eval expressions in environment"
"p -- pretty-print procedure"
"v -- show environment"
"<n> -- pretty-print n-th argument"
"o -- obarray information")))
(define (inspect-command-loop)
(let ((input) (done #f))
(display "inspect> ")
(set! input (read))
(case input
(q
(set! done #t))
(?
(for-each
(lambda (msg)
(display msg)
(newline))
help-text))
(f
(print-frame))
(^
(set! frame 0)
(print-frame))
($
(set! frame (1- (length trace)))
(print-frame))
(u
(if (zero? frame)
(format #t "Already on top frame.~%")
(set! frame (1- frame))
(print-frame)))
(d
(if (= frame (1- (length trace)))
(format #t "Already on bottom frame.~%")
(set! frame (1+ frame))
(print-frame)))
(v
(show (vector-ref (list-ref trace frame) 2)))
(e
(format #t "Type ^D to return to Inspector.~%")
(let loop ()
(display "eval> ")
(set! input (read))
(if (not (eof-object? input))
(begin
(write (eval input
(vector-ref (list-ref trace frame) 2)))
(newline)
(loop))))
(newline))
(p
(pp (vector-ref (list-ref trace frame) 0))
(newline))
(o
(let ((l (map length (oblist))))
(let ((n 0))
(for-each (lambda (x) (set! n (+ x n))) l)
(format #t "~s symbols " n)
(format #t "(maximum bucket: ~s).~%" (apply max l)))))
(else
(cond
((integer? input)
(let ((args (vector-ref (list-ref trace frame) 1)))
(if (or (< input 1) (> input (length args)))
(format #t "No such argument.~%")
(pp (list-ref args (1- input)))
(newline))))
((eof-object? input)
(set! done #t))
(else
(format #t "Invalid command. Type ? for help.~%")))))
(if (not done)
(inspect-command-loop))))
(define (print-frame)
(format #t "~%Frame ~s of ~s:~%~%" (1+ frame) (length trace))
(let* ((f (list-ref trace frame)) (args (vector-ref f 1)))
(format #t "Procedure: ~s~%" (vector-ref f 0))
(format #t "Environment: ~s~%" (vector-ref f 2))
(if (null? args)
(format #t "No arguments.~%")
(fluid-let
((print-depth 2)
(print-length 3))
(do ((i 1 (1+ i)) (args args (cdr args))) ((null? args))
(format #t "Argument ~s: ~s~%" i (car args))))))
(newline))
(set! inspect
(lambda ()
(set! frame 0)
(set! trace (backtrace-list))
(set! trace (cddr trace))
(do ((t trace (cdr t)) (f 1 (1+ f))) ((null? t))
(if (not (null? (vector-ref (car t) 1)))
(let ((last (last-pair (vector-ref (car t) 1))))
(if (not (null? (cdr last)))
(begin
(format #t
"[inspector: fixing improper arglist in frame ~s]~%" f)
(set-cdr! last (cons (cdr last) '())))))))
(format #t "Inspector (type ? for help):~%")
(let loop ()
(if (call-with-current-continuation
(lambda (control-point)
(push-frame control-point)
(inspect-command-loop)
#f))
(begin
(pop-frame)
(loop))))
(newline)
(pop-frame)
(let ((next-frame (car rep-frames)))
(next-frame #t)))))
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