[bpt/guile.git] / module / ice-9 / debugger / command-loop.scm

;;;; Guile Debugger command loop

;;; Copyright (C) 1999, 2001, 2002, 2003, 2006 Free Software Foundation, Inc.
;;;
;;;; This library is free software; you can redistribute it and/or
;;;; modify it under the terms of the GNU Lesser General Public
;;;; License as published by the Free Software Foundation; either
;;;; version 3 of the License, or (at your option) any later version.
;;;; 
;;;; This library is distributed in the hope that it will be useful,
;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;;;; Lesser General Public License for more details.
;;;; 
;;;; You should have received a copy of the GNU Lesser General Public
;;;; License along with this library; if not, write to the Free Software
;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

(define-module (ice-9 debugger command-loop)
  #:use-module ((ice-9 debugger commands) :prefix debugger:)
  #:use-module (ice-9 debugger)
  #:use-module (ice-9 debugger state)
  #:use-module (ice-9 debugging traps)
  #:export (debugger-command-loop
	    debugger-command-loop-error
	    debugger-command-loop-quit)
  #:no-backtrace)

;;; {Interface used by (ice-9 debugger).}

(define (debugger-command-loop state)
  (read-and-dispatch-commands state (current-input-port)))

(define (debugger-command-loop-error message)
  (user-error message))

(define (debugger-command-loop-quit)
  (throw 'exit-debugger))

;;; {Implementation.}
  
(define debugger-prompt "debug> ")

(define (debugger-handler key . args)
  (case key
    ((exit-debugger) #f)
    ((signal)
     ;; Restore stack
     (fluid-set! the-last-stack (fluid-ref before-signal-stack))
     (apply display-error #f (current-error-port) args))
    (else
     (display "Internal debugger error:\n")
     (save-stack debugger-handler)
     (apply throw key args)))
  (throw 'exit-debugger))		;Pop the stack

(define (read-and-dispatch-commands state port)
  (catch 'exit-debugger
    (lambda ()
      (lazy-catch #t
        (lambda ()
	  (with-fluids ((last-command #f))
	    (let loop ()
	      (read-and-dispatch-command state port)
	      (loop))))
	debugger-handler))
    (lambda args
      *unspecified*)))

(define set-readline-prompt! #f)

(define (read-and-dispatch-command state port)
  (if (using-readline?)
      (begin
	;; Import set-readline-prompt! if we haven't already.
	(or set-readline-prompt!
	    (set! set-readline-prompt!
		  (module-ref (resolve-module '(ice-9 readline))
			      'set-readline-prompt!)))
	(set-readline-prompt! debugger-prompt debugger-prompt))
      (display debugger-prompt))
  (force-output)			;This should not be necessary...
  (let ((token (read-token port)))
    (cond ((eof-object? token)
	   (throw 'exit-debugger))
	  ((not token)
	   (discard-rest-of-line port)
	   (catch-user-errors port (lambda () (run-last-command state))))
	  (else
	   (catch-user-errors port
	     (lambda ()
	       (dispatch-command token command-table state port)))))))

(define (run-last-command state)
  (let ((procedure (fluid-ref last-command)))
    (if procedure
	(procedure state))))

(define (catch-user-errors port thunk)
  (catch 'debugger-user-error
	 thunk
	 (lambda (key . objects)
	   (apply user-warning objects)
	   (discard-rest-of-line port))))

(define last-command (make-fluid))

(define (user-warning . objects)
  (for-each (lambda (object)
	      (display object))
	    objects)
  (newline))

(define (user-error . objects)
  (apply throw 'debugger-user-error objects))
\f
;;;; Command dispatch

(define (dispatch-command string table state port)
  (let ((value (command-table-value table string)))
    (if value
	(dispatch-command/value value state port)
	(user-error "Unknown command: " string))))

(define (dispatch-command/value value state port)
  (cond ((command? value)
	 (dispatch-command/command value state port))
	((command-table? value)
	 (dispatch-command/table value state port))
	((list? value)
	 (dispatch-command/name value state port))
	(else
	 (error "Unrecognized command-table value: " value))))

(define (dispatch-command/command command state port)
  (let ((procedure (command-procedure command))
	(arguments ((command-parser command) port)))
    (let ((procedure (lambda (state) (apply procedure state arguments))))
      (warn-about-extra-args port)
      (fluid-set! last-command procedure)
      (procedure state))))

(define (warn-about-extra-args port)
  ;; **** modify this to show the arguments.
  (let ((char (skip-whitespace port)))
    (cond ((eof-object? char) #f)
	  ((char=? #\newline char) (read-char port))
	  (else
	   (user-warning "Extra arguments at end of line: "
			 (read-rest-of-line port))))))

(define (dispatch-command/table table state port)
  (let ((token (read-token port)))
    (if (or (eof-object? token)
	    (not token))
	(user-error "Command name too short.")
	(dispatch-command token table state port))))

(define (dispatch-command/name name state port)
  (let ((value (lookup-command name)))
    (cond ((not value)
	   (apply user-error "Unknown command name: " name))
	  ((command-table? value)
	   (apply user-error "Partial command name: " name))
	  (else
	   (dispatch-command/value value state port)))))
\f
;;;; Command definition

(define (define-command name argument-template procedure)
  (let ((name (canonicalize-command-name name)))
    (add-command name
		 (make-command name
			       (argument-template->parser argument-template)
			       (procedure-documentation procedure)
			       procedure)
		 command-table)
    name))

(define (define-command-alias name1 name2)
  (let ((name1 (canonicalize-command-name name1)))
    (add-command name1 (canonicalize-command-name name2) command-table)
    name1))
\f
(define (argument-template->parser template)
  ;; Deliberately handles only cases that occur in "commands.scm".
  (cond ((eq? 'tokens template)
	 (lambda (port)
	   (let loop ((tokens '()))
	     (let ((token (read-token port)))
	       (if (or (eof-object? token)
		       (not token))
		   (list (reverse! tokens))
		   (loop (cons token tokens)))))))
	((null? template)
	 (lambda (port)
	   '()))
	((and (pair? template)
	      (null? (cdr template))
	      (eq? 'object (car template)))
	 (lambda (port)
	   (list (read port))))
	((and (pair? template)
	      (equal? ''optional (car template))
	      (pair? (cdr template))
	      (null? (cddr template)))
	 (case (cadr template)
	   ((token)
	    (lambda (port)
	      (let ((token (read-token port)))
		(if (or (eof-object? token)
			(not token))
		    (list #f)
		    (list token)))))
	   ((exact-integer)
	    (lambda (port)
	      (list (parse-optional-exact-integer port))))
	   ((exact-nonnegative-integer)
	    (lambda (port)
	      (list (parse-optional-exact-nonnegative-integer port))))
	   ((object)
	    (lambda (port)
	      (list (parse-optional-object port))))
	   (else
	    (error "Malformed argument template: " template))))
	(else
	 (error "Malformed argument template: " template))))

(define (parse-optional-exact-integer port)
  (let ((object (parse-optional-object port)))
    (if (or (not object)
	    (and (integer? object)
		 (exact? object)))
	object
	(user-error "Argument not an exact integer: " object))))

(define (parse-optional-exact-nonnegative-integer port)
  (let ((object (parse-optional-object port)))
    (if (or (not object)
	    (and (integer? object)
		 (exact? object)
		 (not (negative? object))))
	object
	(user-error "Argument not an exact non-negative integer: " object))))

(define (parse-optional-object port)
  (let ((terminator (skip-whitespace port)))
    (if (or (eof-object? terminator)
	    (eq? #\newline terminator))
	#f
	(let ((object (read port)))
	  (if (eof-object? object)
	      #f
	      object)))))
\f
;;;; Command tables

(define (lookup-command name)
  (let loop ((table command-table) (strings name))
    (let ((value (command-table-value table (car strings))))
      (cond ((or (not value) (null? (cdr strings))) value)
	    ((command-table? value) (loop value (cdr strings)))
	    (else #f)))))

(define (command-table-value table string)
  (let ((entry (command-table-entry table string)))
    (and entry
	 (caddr entry))))

(define (command-table-entry table string)
  (let loop ((entries (command-table-entries table)))
    (and (not (null? entries))
	 (let ((entry (car entries)))
	   (if (and (<= (cadr entry)
			(string-length string)
			(string-length (car entry)))
		    (= (string-length string)
		       (match-strings (car entry) string)))
	       entry
	       (loop (cdr entries)))))))

(define (match-strings s1 s2)
  (let ((n (min (string-length s1) (string-length s2))))
    (let loop ((i 0))
      (cond ((= i n) i)
	    ((char=? (string-ref s1 i) (string-ref s2 i)) (loop (+ i 1)))
	    (else i)))))

(define (write-command-name name)
  (display (car name))
  (for-each (lambda (string)
	      (write-char #\space)
	      (display string))
	    (cdr name)))
\f
(define (add-command name value table)
  (let loop ((strings name) (table table))
    (let ((entry
	   (or (let loop ((entries (command-table-entries table)))
		 (and (not (null? entries))
		      (if (string=? (car strings) (caar entries))
			  (car entries)
			  (loop (cdr entries)))))
	       (let ((entry (list (car strings) #f #f)))
		 (let ((entries
			(let ((entries (command-table-entries table)))
			  (if (or (null? entries)
				  (string<? (car strings) (caar entries)))
			      (cons entry entries)
			      (begin
				(let loop ((prev entries) (this (cdr entries)))
				  (if (or (null? this)
					  (string<? (car strings) (caar this)))
				      (set-cdr! prev (cons entry this))
				      (loop this (cdr this))))
				entries)))))
		   (compute-string-abbreviations! entries)
		   (set-command-table-entries! table entries))
		 entry))))
      (if (null? (cdr strings))
	  (set-car! (cddr entry) value)
	  (loop (cdr strings)
		(if (command-table? (caddr entry))
		    (caddr entry)
		    (let ((table (make-command-table '())))
		      (set-car! (cddr entry) table)
		      table)))))))

(define (canonicalize-command-name name)
  (cond ((and (string? name)
	      (not (string-null? name)))
	 (list name))
	((let loop ((name name))
	   (and (pair? name)
		(string? (car name))
		(not (string-null? (car name)))
		(or (null? (cdr name))
		    (loop (cdr name)))))
	 name)
	(else
	 (error "Illegal command name: " name))))

(define (compute-string-abbreviations! entries)
  (let loop ((entries entries) (index 0))
    (let ((groups '()))
      (for-each
       (lambda (entry)
	 (let* ((char (string-ref (car entry) index))
		(group (assv char groups)))
	   (if group
	       (set-cdr! group (cons entry (cdr group)))
	       (set! groups
		     (cons (list char entry)
			   groups)))))
       entries)
      (for-each
       (lambda (group)
	 (let ((index (+ index 1)))
	   (if (null? (cddr group))
	       (set-car! (cdadr group) index)
	       (loop (let ((entry
			    (let loop ((entries (cdr group)))
			      (and (not (null? entries))
				   (if (= index (string-length (caar entries)))
				       (car entries)
				       (loop (cdr entries)))))))
		       (if entry
			   (begin
			     (set-car! (cdr entry) index)
			     (delq entry (cdr group)))
			   (cdr group)))
		     index))))
       groups))))
\f
;;;; Data structures

(define command-table-rtd (make-record-type "command-table" '(entries)))
(define make-command-table (record-constructor command-table-rtd '(entries)))
(define command-table? (record-predicate command-table-rtd))
(define command-table-entries (record-accessor command-table-rtd 'entries))
(define set-command-table-entries!
  (record-modifier command-table-rtd 'entries))

(define command-rtd
  (make-record-type "command"
		    '(name parser documentation procedure)))

(define make-command
  (record-constructor command-rtd
		      '(name parser documentation procedure)))

(define command? (record-predicate command-rtd))
(define command-name (record-accessor command-rtd 'name))
(define command-parser (record-accessor command-rtd 'parser))
(define command-documentation (record-accessor command-rtd 'documentation))
(define command-procedure (record-accessor command-rtd 'procedure))
\f
;;;; Character parsing

(define (read-token port)
  (letrec
      ((loop
	(lambda (chars)
	  (let ((char (peek-char port)))
	    (cond ((eof-object? char)
		   (do-eof char chars))
		  ((char=? #\newline char)
		   (do-eot chars))
		  ((char-whitespace? char)
		   (do-eot chars))
		  ((char=? #\# char)
		   (read-char port)
		   (let ((terminator (skip-comment port)))
		     (if (eof-object? char)
			 (do-eof char chars)
			 (do-eot chars))))
		  (else
		   (read-char port)
		   (loop (cons char chars)))))))
       (do-eof
	(lambda (eof chars)
	  (if (null? chars)
	      eof
	      (do-eot chars))))
       (do-eot
	(lambda (chars)
	  (if (null? chars)
	      #f
	      (list->string (reverse! chars))))))
    (skip-whitespace port)
    (loop '())))

(define (skip-whitespace port)
  (let ((char (peek-char port)))
    (cond ((or (eof-object? char)
	       (char=? #\newline char))
	   char)
	  ((char-whitespace? char)
	   (read-char port)
	   (skip-whitespace port))
	  ((char=? #\# char)
	   (read-char port)
	   (skip-comment port))
	  (else char))))

(define (skip-comment port)
  (let ((char (peek-char port)))
    (if (or (eof-object? char)
	    (char=? #\newline char))
	char
	(begin
	  (read-char port)
	  (skip-comment port)))))

(define (read-rest-of-line port)
  (let loop ((chars '()))
    (let ((char (read-char port)))
      (if (or (eof-object? char)
	      (char=? #\newline char))
	  (list->string (reverse! chars))
	  (loop (cons char chars))))))

(define (discard-rest-of-line port)
  (let loop ()
    (if (not (let ((char (read-char port)))
	       (or (eof-object? char)
		   (char=? #\newline char))))
	(loop))))
\f
;;;; Commands

(define command-table (make-command-table '()))

(define-command "help" 'tokens
  (lambda (state tokens)
    "Type \"help\" followed by a command name for full documentation."
    (let loop ((name (if (null? tokens) '("help") tokens)))
      (let ((value (lookup-command name)))
	(cond ((not value)
	       (write-command-name name)
	       (display " is not a known command name.")
	       (newline))
	      ((command? value)
	       (display (command-documentation value))
	       (newline)
	       (if (equal? '("help") (command-name value))
		   (begin
		     (display "Available commands are:")
		     (newline)
		     (for-each (lambda (entry)
				 (if (not (list? (caddr entry)))
				     (begin
				       (display "  ")
				       (display (car entry))
				       (newline))))
			       (command-table-entries command-table)))))
	      ((command-table? value)
	       (display "The \"")
	       (write-command-name name)
	       (display "\" command requires a subcommand.")
	       (newline)
	       (display "Available subcommands are:")
	       (newline)
	       (for-each (lambda (entry)
			   (if (not (list? (caddr entry)))
			       (begin
				 (display "  ")
				 (write-command-name name)
				 (write-char #\space)
				 (display (car entry))
				 (newline))))
			 (command-table-entries value)))
	      ((list? value)
	       (loop value))
	      (else
	       (error "Unknown value from lookup-command:" value)))))
    state))

(define-command "frame" '('optional exact-nonnegative-integer) debugger:frame)

(define-command "position" '() debugger:position)

(define-command "up" '('optional exact-integer) debugger:up)

(define-command "down" '('optional exact-integer) debugger:down)
\f
(define-command "backtrace" '('optional exact-integer) debugger:backtrace)

(define-command "evaluate" '(object) debugger:evaluate)

(define-command '("info" "args") '() debugger:info-args)

(define-command '("info" "frame") '() debugger:info-frame)

(define-command "quit" '()
  (lambda (state)
    "Exit the debugger."
    (debugger-command-loop-quit)))

(define-command-alias "f" "frame")
(define-command-alias '("info" "f") '("info" "frame"))
(define-command-alias "bt" "backtrace")
(define-command-alias "where" "backtrace")
(define-command-alias "p" "evaluate")
(define-command-alias '("info" "stack") "backtrace")

(define-command "continue" '() debugger:continue)

(define-command "finish" '() debugger:finish)

(define-command "step" '('optional exact-integer) debugger:step)

(define-command "next" '('optional exact-integer) debugger:next)
Commit	Line	Data
8ee7506b NJ	1	;;;; Guile Debugger command loop
8ee7506b NJ	2
cd5fea8d	3	;;; Copyright (C) 1999, 2001, 2002, 2003, 2006 Free Software Foundation, Inc.
8ee7506b	4	;;;
53befeb7 NJ	5	;;;; This library is free software; you can redistribute it and/or
	6	;;;; modify it under the terms of the GNU Lesser General Public
	7	;;;; License as published by the Free Software Foundation; either
	8	;;;; version 3 of the License, or (at your option) any later version.
	9	;;;;
	10	;;;; This library is distributed in the hope that it will be useful,
	11	;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	;;;; Lesser General Public License for more details.
	14	;;;;
	15	;;;; You should have received a copy of the GNU Lesser General Public
	16	;;;; License along with this library; if not, write to the Free Software
	17	;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
8ee7506b NJ	18
8ee7506b NJ	19	(define-module (ice-9 debugger command-loop)
c614a00b	20	#:use-module ((ice-9 debugger commands) :prefix debugger:)
ba5f8bf4 NJ	21	#:use-module (ice-9 debugger)
	22	#:use-module (ice-9 debugger state)
	23	#:use-module (ice-9 debugging traps)
8ee7506b NJ	24	#:export (debugger-command-loop
	25	debugger-command-loop-error
	26	debugger-command-loop-quit)
	27	#:no-backtrace)
	28
8ee7506b NJ	29	;;; {Interface used by (ice-9 debugger).}
	30
	31	(define (debugger-command-loop state)
	32	(read-and-dispatch-commands state (current-input-port)))
	33
	34	(define (debugger-command-loop-error message)
	35	(user-error message))
	36
	37	(define (debugger-command-loop-quit)
	38	(throw 'exit-debugger))
	39
	40	;;; {Implementation.}
	41
	42	(define debugger-prompt "debug> ")
	43
	44	(define (debugger-handler key . args)
	45	(case key
	46	((exit-debugger) #f)
	47	((signal)
	48	;; Restore stack
	49	(fluid-set! the-last-stack (fluid-ref before-signal-stack))
	50	(apply display-error #f (current-error-port) args))
	51	(else
	52	(display "Internal debugger error:\n")
	53	(save-stack debugger-handler)
	54	(apply throw key args)))
	55	(throw 'exit-debugger)) ;Pop the stack
	56
	57	(define (read-and-dispatch-commands state port)
	58	(catch 'exit-debugger
	59	(lambda ()
	60	(lazy-catch #t
	61	(lambda ()
	62	(with-fluids ((last-command #f))
	63	(let loop ()
	64	(read-and-dispatch-command state port)
	65	(loop))))
	66	debugger-handler))
	67	(lambda args
	68	unspecified)))
	69
9124ba8d NJ	70	(define set-readline-prompt! #f)
9124ba8d NJ	71
8ee7506b NJ	72	(define (read-and-dispatch-command state port)
8ee7506b NJ	73	(if (using-readline?)
9124ba8d NJ	74	(begin
	75	;; Import set-readline-prompt! if we haven't already.
	76	(or set-readline-prompt!
	77	(set! set-readline-prompt!
	78	(module-ref (resolve-module '(ice-9 readline))
	79	'set-readline-prompt!)))
	80	(set-readline-prompt! debugger-prompt debugger-prompt))
8ee7506b NJ	81	(display debugger-prompt))
	82	(force-output) ;This should not be necessary...
	83	(let ((token (read-token port)))
	84	(cond ((eof-object? token)
	85	(throw 'exit-debugger))
	86	((not token)
	87	(discard-rest-of-line port)
	88	(catch-user-errors port (lambda () (run-last-command state))))
	89	(else
	90	(catch-user-errors port
	91	(lambda ()
	92	(dispatch-command token command-table state port)))))))
	93
	94	(define (run-last-command state)
	95	(let ((procedure (fluid-ref last-command)))
	96	(if procedure
	97	(procedure state))))
	98
	99	(define (catch-user-errors port thunk)
	100	(catch 'debugger-user-error
	101	thunk
	102	(lambda (key . objects)
	103	(apply user-warning objects)
	104	(discard-rest-of-line port))))
	105
	106	(define last-command (make-fluid))
	107
	108	(define (user-warning . objects)
	109	(for-each (lambda (object)
	110	(display object))
	111	objects)
	112	(newline))
	113
	114	(define (user-error . objects)
	115	(apply throw 'debugger-user-error objects))
	116	\f
	117	;;;; Command dispatch
	118
	119	(define (dispatch-command string table state port)
	120	(let ((value (command-table-value table string)))
	121	(if value
	122	(dispatch-command/value value state port)
	123	(user-error "Unknown command: " string))))
	124
	125	(define (dispatch-command/value value state port)
	126	(cond ((command? value)
	127	(dispatch-command/command value state port))
	128	((command-table? value)
	129	(dispatch-command/table value state port))
	130	((list? value)
	131	(dispatch-command/name value state port))
	132	(else
	133	(error "Unrecognized command-table value: " value))))
	134
	135	(define (dispatch-command/command command state port)
	136	(let ((procedure (command-procedure command))
	137	(arguments ((command-parser command) port)))
	138	(let ((procedure (lambda (state) (apply procedure state arguments))))
	139	(warn-about-extra-args port)
	140	(fluid-set! last-command procedure)
	141	(procedure state))))
	142
	143	(define (warn-about-extra-args port)
	144	;; **** modify this to show the arguments.
145	(let ((char (skip-whitespace port)))
146	(cond ((eof-object? char) #f)
147	((char=? #\newline char) (read-char port))
148	(else
149	(user-warning "Extra arguments at end of line: "
150	(read-rest-of-line port))))))
151
152	(define (dispatch-command/table table state port)
153	(let ((token (read-token port)))
154	(if (or (eof-object? token)
155	(not token))
156	(user-error "Command name too short.")
157	(dispatch-command token table state port))))
158
159	(define (dispatch-command/name name state port)
160	(let ((value (lookup-command name)))
161	(cond ((not value)
162	(apply user-error "Unknown command name: " name))
163	((command-table? value)
164	(apply user-error "Partial command name: " name))
165	(else
166	(dispatch-command/value value state port)))))
167	\f
168	;;;; Command definition
169
170	(define (define-command name argument-template procedure)
171	(let ((name (canonicalize-command-name name)))
172	(add-command name
173	(make-command name
174	(argument-template->parser argument-template)
175	(procedure-documentation procedure)
176	procedure)
177	command-table)
178	name))
179
180	(define (define-command-alias name1 name2)
181	(let ((name1 (canonicalize-command-name name1)))
182	(add-command name1 (canonicalize-command-name name2) command-table)
183	name1))
184	\f
185	(define (argument-template->parser template)
186	;; Deliberately handles only cases that occur in "commands.scm".
187	(cond ((eq? 'tokens template)
188	(lambda (port)
189	(let loop ((tokens '()))
190	(let ((token (read-token port)))
191	(if (or (eof-object? token)
192	(not token))
193	(list (reverse! tokens))
194	(loop (cons token tokens)))))))
195	((null? template)
196	(lambda (port)
197	'()))
198	((and (pair? template)
199	(null? (cdr template))
200	(eq? 'object (car template)))
201	(lambda (port)
202	(list (read port))))
203	((and (pair? template)
204	(equal? ''optional (car template))
205	(pair? (cdr template))
206	(null? (cddr template)))
207	(case (cadr template)
208	((token)
209	(lambda (port)
210	(let ((token (read-token port)))
211	(if (or (eof-object? token)
212	(not token))
213	(list #f)
214	(list token)))))
215	((exact-integer)
216	(lambda (port)
217	(list (parse-optional-exact-integer port))))
218	((exact-nonnegative-integer)
219	(lambda (port)
220	(list (parse-optional-exact-nonnegative-integer port))))
221	((object)
222	(lambda (port)
223	(list (parse-optional-object port))))
224	(else
225	(error "Malformed argument template: " template))))
226	(else
227	(error "Malformed argument template: " template))))
228
229	(define (parse-optional-exact-integer port)
230	(let ((object (parse-optional-object port)))
231	(if (or (not object)
232	(and (integer? object)
233	(exact? object)))
234	object
235	(user-error "Argument not an exact integer: " object))))
236
237	(define (parse-optional-exact-nonnegative-integer port)
238	(let ((object (parse-optional-object port)))
239	(if (or (not object)
240	(and (integer? object)
241	(exact? object)
242	(not (negative? object))))
243	object
244	(user-error "Argument not an exact non-negative integer: " object))))
245
246	(define (parse-optional-object port)
247	(let ((terminator (skip-whitespace port)))
248	(if (or (eof-object? terminator)
249	(eq? #\newline terminator))
250	#f
251	(let ((object (read port)))
252	(if (eof-object? object)
253	#f
254	object)))))
255	\f
256	;;;; Command tables
257
258	(define (lookup-command name)
259	(let loop ((table command-table) (strings name))
260	(let ((value (command-table-value table (car strings))))
261	(cond ((or (not value) (null? (cdr strings))) value)
262	((command-table? value) (loop value (cdr strings)))
263	(else #f)))))
264
265	(define (command-table-value table string)
266	(let ((entry (command-table-entry table string)))
267	(and entry
268	(caddr entry))))
269
270	(define (command-table-entry table string)
271	(let loop ((entries (command-table-entries table)))
272	(and (not (null? entries))
273	(let ((entry (car entries)))
274	(if (and (<= (cadr entry)
275	(string-length string)
276	(string-length (car entry)))
277	(= (string-length string)
278	(match-strings (car entry) string)))
279	entry
280	(loop (cdr entries)))))))
281
282	(define (match-strings s1 s2)
283	(let ((n (min (string-length s1) (string-length s2))))
284	(let loop ((i 0))
285	(cond ((= i n) i)
286	((char=? (string-ref s1 i) (string-ref s2 i)) (loop (+ i 1)))
287	(else i)))))
288
289	(define (write-command-name name)
290	(display (car name))
291	(for-each (lambda (string)
292	(write-char #\space)
293	(display string))
294	(cdr name)))
295	\f
296	(define (add-command name value table)
297	(let loop ((strings name) (table table))
298	(let ((entry
299	(or (let loop ((entries (command-table-entries table)))
300	(and (not (null? entries))
301	(if (string=? (car strings) (caar entries))
302	(car entries)
303	(loop (cdr entries)))))
304	(let ((entry (list (car strings) #f #f)))
305	(let ((entries
306	(let ((entries (command-table-entries table)))
307	(if (or (null? entries)
308	(string<? (car strings) (caar entries)))
309	(cons entry entries)
310	(begin
311	(let loop ((prev entries) (this (cdr entries)))
312	(if (or (null? this)
313	(string<? (car strings) (caar this)))
314	(set-cdr! prev (cons entry this))
315	(loop this (cdr this))))
316	entries)))))
317	(compute-string-abbreviations! entries)
318	(set-command-table-entries! table entries))
319	entry))))
320	(if (null? (cdr strings))
321	(set-car! (cddr entry) value)
322	(loop (cdr strings)
323	(if (command-table? (caddr entry))
324	(caddr entry)
325	(let ((table (make-command-table '())))
326	(set-car! (cddr entry) table)
327	table)))))))
328
329	(define (canonicalize-command-name name)
330	(cond ((and (string? name)
331	(not (string-null? name)))
332	(list name))
333	((let loop ((name name))
334	(and (pair? name)
335	(string? (car name))
336	(not (string-null? (car name)))
337	(or (null? (cdr name))
338	(loop (cdr name)))))
339	name)
340	(else
341	(error "Illegal command name: " name))))
342
343	(define (compute-string-abbreviations! entries)
344	(let loop ((entries entries) (index 0))
345	(let ((groups '()))
346	(for-each
347	(lambda (entry)
348	(let* ((char (string-ref (car entry) index))
349	(group (assv char groups)))
350	(if group
351	(set-cdr! group (cons entry (cdr group)))
352	(set! groups
353	(cons (list char entry)
354	groups)))))
355	entries)
356	(for-each
357	(lambda (group)
358	(let ((index (+ index 1)))
359	(if (null? (cddr group))
360	(set-car! (cdadr group) index)
361	(loop (let ((entry
362	(let loop ((entries (cdr group)))
363	(and (not (null? entries))
364	(if (= index (string-length (caar entries)))
365	(car entries)
366	(loop (cdr entries)))))))
367	(if entry
368	(begin
369	(set-car! (cdr entry) index)
370	(delq entry (cdr group)))
371	(cdr group)))
372	index))))
373	groups))))
374	\f
375	;;;; Data structures
376
377	(define command-table-rtd (make-record-type "command-table" '(entries)))
378	(define make-command-table (record-constructor command-table-rtd '(entries)))
379	(define command-table? (record-predicate command-table-rtd))
380	(define command-table-entries (record-accessor command-table-rtd 'entries))
381	(define set-command-table-entries!
382	(record-modifier command-table-rtd 'entries))
383
384	(define command-rtd
385	(make-record-type "command"
386	'(name parser documentation procedure)))
387
388	(define make-command
389	(record-constructor command-rtd
390	'(name parser documentation procedure)))
391
392	(define command? (record-predicate command-rtd))
393	(define command-name (record-accessor command-rtd 'name))
394	(define command-parser (record-accessor command-rtd 'parser))
395	(define command-documentation (record-accessor command-rtd 'documentation))
396	(define command-procedure (record-accessor command-rtd 'procedure))
397	\f
398	;;;; Character parsing
399
400	(define (read-token port)
401	(letrec
402	((loop
403	(lambda (chars)
404	(let ((char (peek-char port)))
405	(cond ((eof-object? char)
406	(do-eof char chars))
407	((char=? #\newline char)
408	(do-eot chars))
409	((char-whitespace? char)
410	(do-eot chars))
411	((char=? #\# char)
412	(read-char port)
413	(let ((terminator (skip-comment port)))
414	(if (eof-object? char)
415	(do-eof char chars)
416	(do-eot chars))))
417	(else
418	(read-char port)
419	(loop (cons char chars)))))))
420	(do-eof
421	(lambda (eof chars)
422	(if (null? chars)
423	eof
424	(do-eot chars))))
425	(do-eot
426	(lambda (chars)
427	(if (null? chars)
428	#f
429	(list->string (reverse! chars))))))
430	(skip-whitespace port)
431	(loop '())))
432
433	(define (skip-whitespace port)
434	(let ((char (peek-char port)))
435	(cond ((or (eof-object? char)
436	(char=? #\newline char))
437	char)
438	((char-whitespace? char)
439	(read-char port)
440	(skip-whitespace port))
441	((char=? #\# char)
442	(read-char port)
443	(skip-comment port))
444	(else char))))
445
446	(define (skip-comment port)
447	(let ((char (peek-char port)))
448	(if (or (eof-object? char)
449	(char=? #\newline char))
450	char
451	(begin
452	(read-char port)
453	(skip-comment port)))))
454
455	(define (read-rest-of-line port)
456	(let loop ((chars '()))
457	(let ((char (read-char port)))
458	(if (or (eof-object? char)
459	(char=? #\newline char))
460	(list->string (reverse! chars))
461	(loop (cons char chars))))))
462
463	(define (discard-rest-of-line port)
464	(let loop ()
465	(if (not (let ((char (read-char port)))
466	(or (eof-object? char)
467	(char=? #\newline char))))
468	(loop))))
469	\f
470	;;;; Commands
471
472	(define command-table (make-command-table '()))
473
474	(define-command "help" 'tokens
475	(lambda (state tokens)
476	"Type \"help\" followed by a command name for full documentation."
477	(let loop ((name (if (null? tokens) '("help") tokens)))
478	(let ((value (lookup-command name)))
479	(cond ((not value)
480	(write-command-name name)
481	(display " is not a known command name.")
482	(newline))
483	((command? value)
484	(display (command-documentation value))
485	(newline)
486	(if (equal? '("help") (command-name value))
487	(begin
488	(display "Available commands are:")
489	(newline)
490	(for-each (lambda (entry)
491	(if (not (list? (caddr entry)))
492	(begin
493	(display " ")
494	(display (car entry))
495	(newline))))
496	(command-table-entries command-table)))))
497	((command-table? value)
498	(display "The \"")
499	(write-command-name name)
500	(display "\" command requires a subcommand.")
501	(newline)
502	(display "Available subcommands are:")
503	(newline)
504	(for-each (lambda (entry)
505	(if (not (list? (caddr entry)))
506	(begin
507	(display " ")
508	(write-command-name name)
509	(write-char #\space)
510	(display (car entry))
511	(newline))))
512	(command-table-entries value)))
513	((list? value)
514	(loop value))
515	(else
516	(error "Unknown value from lookup-command:" value)))))
517	state))
518
c614a00b	519	(define-command "frame" '('optional exact-nonnegative-integer) debugger:frame)
8ee7506b	520
c614a00b	521	(define-command "position" '() debugger:position)
8ee7506b	522
c614a00b	523	(define-command "up" '('optional exact-integer) debugger:up)
8ee7506b	524
c614a00b	525	(define-command "down" '('optional exact-integer) debugger:down)
8ee7506b	526	\f
c614a00b	527	(define-command "backtrace" '('optional exact-integer) debugger:backtrace)
8ee7506b	528
c614a00b	529	(define-command "evaluate" '(object) debugger:evaluate)
8ee7506b	530
c614a00b	531	(define-command '("info" "args") '() debugger:info-args)
8ee7506b	532
c614a00b	533	(define-command '("info" "frame") '() debugger:info-frame)
8ee7506b NJ	534
	535	(define-command "quit" '()
	536	(lambda (state)
	537	"Exit the debugger."
	538	(debugger-command-loop-quit)))
	539
	540	(define-command-alias "f" "frame")
	541	(define-command-alias '("info" "f") '("info" "frame"))
	542	(define-command-alias "bt" "backtrace")
	543	(define-command-alias "where" "backtrace")
	544	(define-command-alias "p" "evaluate")
	545	(define-command-alias '("info" "stack") "backtrace")
ba5f8bf4 NJ	546
	547	(define-command "continue" '() debugger:continue)
	548
	549	(define-command "finish" '() debugger:finish)
	550
	551	(define-command "step" '('optional exact-integer) debugger:step)
	552
	553	(define-command "next" '('optional exact-integer) debugger:next)