summaryrefslogtreecommitdiff
path: root/module/ice-9/debugger.scm
blob: 06f7ed2308933c8ae0ca29b8d68ea94acce1c085 (about) (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
;;;; Guile Debugger

;;; Copyright (C) 1999, 2001, 2002, 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)
  #:use-module (ice-9 debugger command-loop)
  #:use-module (ice-9 debugger state)
  #:use-module (ice-9 debugger utils)
  #:use-module (ice-9 format)
  #:export (debug-stack
	    debug
	    debug-last-error
	    debugger-error
	    debugger-quit
	    debugger-input-port
	    debugger-output-port
	    debug-on-error)
  #:no-backtrace)

;;; The old (ice-9 debugger) has been factored into its constituent
;;; parts:
;;;
;;; (ice-9 debugger) - public interface to all of the following
;;;
;;; (... commands) - procedures implementing the guts of the commands
;;;                  provided by the interactive debugger
;;;
;;; (... command-loop) - binding these commands into the interactive
;;;                      debugger command loop
;;;
;;; (... state) - implementation of an object that tracks current
;;;               debugger state
;;;
;;; (... utils) - utilities for printing out frame and stack
;;;               information in various formats
;;;
;;; The division between (... commands) and (... command-loop) exists
;;; because I (NJ) have another generic command loop implementation
;;; under development, and I want to be able to switch easily between
;;; that and the command loop implementation here.  Thus the
;;; procedures in this file delegate to a debugger command loop
;;; implementation via the `debugger-command-loop-*' interface.  The
;;; (ice-9 debugger command-loop) implementation can be replaced by
;;; any other that implements the `debugger-command-loop-*' interface
;;; simply by changing the relevant #:use-module line above.
;;;
;;; - Neil Jerram <neil@ossau.uklinux.net> 2002-10-26, updated 2005-07-09

(define *not-yet-introduced* #t)

(define (debug-stack stack . flags)
  "Invoke the Guile debugger to explore the specified @var{stack}.

@var{flags}, if present, are keywords indicating characteristics of
the debugging session: the valid keywords are as follows.

@table @code
@item #:continuable
Indicates that the debugger is being invoked from a context (such as
an evaluator trap handler) where it is possible to return from the
debugger and continue normal code execution.  This enables the
@dfn{continuing execution} commands, for example @code{continue} and
@code{step}.

@item #:with-introduction
Indicates that the debugger should display an introductory message.
@end table"
  (start-stack 'debugger
    (let ((state (apply make-state stack 0 flags)))
      (with-input-from-port (debugger-input-port)
	(lambda ()
	  (with-output-to-port (debugger-output-port)
	    (lambda ()
	      (if (or *not-yet-introduced*
		      (memq #:with-introduction flags))
		  (let ((ssize (stack-length stack)))
		    (display "This is the Guile debugger -- for help, type `help'.\n")
		    (set! *not-yet-introduced* #f)
		    (if (= ssize 1)
			(display "There is 1 frame on the stack.\n\n")
			(format #t "There are ~A frames on the stack.\n\n" ssize))))
	      (write-state-short state)
	      (debugger-command-loop state))))))))

(define (debug)
  "Invoke the Guile debugger to explore the context of the last error."
  (let ((stack (fluid-ref the-last-stack)))
    (if stack
	(debug-stack stack)
	(display "Nothing to debug.\n"))))

(define debug-last-error debug)

(define (debugger-error message)
  "Signal a debugger usage error with message @var{message}."
  (debugger-command-loop-error message))

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

;;; {Debugger Input and Output Ports}

(define debugger-input-port
  (let ((input-port (current-input-port)))
    (make-procedure-with-setter
     (lambda () input-port)
     (lambda (port) (set! input-port port)))))

(define debugger-output-port
  (let ((output-port (current-output-port)))
    (make-procedure-with-setter
     (lambda () output-port)
     (lambda (port) (set! output-port port)))))

;;; {Debug on Error}

(define (debug-on-error syms)
  "Enable or disable debug on error."
  (set! pre-unwind-handler-dispatch
	(if syms
	    (lambda (key . args)
	      (if (memq key syms)
		  (begin
		    (debug-stack (make-stack #t pre-unwind-handler-dispatch)
				 #:with-introduction
				 #:continuable)
		    (throw 'abort key)))
	      (apply default-pre-unwind-handler key args))
	    default-pre-unwind-handler)))

;;; (ice-9 debugger) ends here.