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73804d4b | 1 | @comment -*-texinfo-*- |
969fe9b5 | 2 | @c This is part of the GNU Emacs Lisp Reference Manual. |
73b0cd50 | 3 | @c Copyright (C) 1992-1994, 1998-1999, 2001-2011 Free Software Foundation, Inc. |
969fe9b5 | 4 | @c See the file elisp.texi for copying conditions. |
73804d4b | 5 | |
177c0ea7 JB |
6 | @c This file can also be used by an independent Edebug User |
7 | @c Manual in which case the Edebug node below should be used | |
73804d4b RS |
8 | @c with the following links to the Bugs section and to the top level: |
9 | ||
10 | @c , Bugs and Todo List, Top, Top | |
11 | ||
1911e6e5 | 12 | @node Edebug, Syntax Errors, Debugger, Debugging |
73804d4b | 13 | @section Edebug |
77bf576c | 14 | @cindex Edebug debugging facility |
73804d4b | 15 | |
622fa380 | 16 | Edebug is a source-level debugger for Emacs Lisp programs, with which |
73804d4b RS |
17 | you can: |
18 | ||
19 | @itemize @bullet | |
20 | @item | |
21 | Step through evaluation, stopping before and after each expression. | |
22 | ||
23 | @item | |
24 | Set conditional or unconditional breakpoints. | |
25 | ||
26 | @item | |
27 | Stop when a specified condition is true (the global break event). | |
28 | ||
29 | @item | |
30 | Trace slow or fast, stopping briefly at each stop point, or | |
31 | at each breakpoint. | |
32 | ||
33 | @item | |
34 | Display expression results and evaluate expressions as if outside of | |
35 | Edebug. | |
36 | ||
177c0ea7 | 37 | @item |
a9f0a989 | 38 | Automatically re-evaluate a list of expressions and |
73804d4b RS |
39 | display their results each time Edebug updates the display. |
40 | ||
41 | @item | |
622fa380 | 42 | Output trace information on function calls and returns. |
73804d4b RS |
43 | |
44 | @item | |
45 | Stop when an error occurs. | |
46 | ||
47 | @item | |
48 | Display a backtrace, omitting Edebug's own frames. | |
49 | ||
50 | @item | |
51 | Specify argument evaluation for macros and defining forms. | |
52 | ||
53 | @item | |
54 | Obtain rudimentary coverage testing and frequency counts. | |
55 | @end itemize | |
56 | ||
57 | The first three sections below should tell you enough about Edebug to | |
622fa380 | 58 | start using it. |
73804d4b RS |
59 | |
60 | @menu | |
d24880de GM |
61 | * Using Edebug:: Introduction to use of Edebug. |
62 | * Instrumenting:: You must instrument your code | |
63 | in order to debug it with Edebug. | |
73804d4b | 64 | * Modes: Edebug Execution Modes. Execution modes, stopping more or less often. |
d24880de GM |
65 | * Jumping:: Commands to jump to a specified place. |
66 | * Misc: Edebug Misc. Miscellaneous commands. | |
c5f8bf2d | 67 | * Breaks:: Setting breakpoints to make the program stop. |
d24880de GM |
68 | * Trapping Errors:: Trapping errors with Edebug. |
69 | * Views: Edebug Views. Views inside and outside of Edebug. | |
70 | * Eval: Edebug Eval. Evaluating expressions within Edebug. | |
71 | * Eval List:: Expressions whose values are displayed | |
72 | each time you enter Edebug. | |
73 | * Printing in Edebug:: Customization of printing. | |
74 | * Trace Buffer:: How to produce trace output in a buffer. | |
75 | * Coverage Testing:: How to test evaluation coverage. | |
76 | * The Outside Context:: Data that Edebug saves and restores. | |
77 | * Edebug and Macros:: Specifying how to handle macro calls. | |
78 | * Options: Edebug Options. Option variables for customizing Edebug. | |
73804d4b RS |
79 | @end menu |
80 | ||
81 | @node Using Edebug | |
82 | @subsection Using Edebug | |
83 | ||
84 | To debug a Lisp program with Edebug, you must first @dfn{instrument} | |
85 | the Lisp code that you want to debug. A simple way to do this is to | |
86 | first move point into the definition of a function or macro and then do | |
87 | @kbd{C-u C-M-x} (@code{eval-defun} with a prefix argument). See | |
88 | @ref{Instrumenting}, for alternative ways to instrument code. | |
89 | ||
90 | Once a function is instrumented, any call to the function activates | |
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91 | Edebug. Depending on which Edebug execution mode you have selected, |
92 | activating Edebug may stop execution and let you step through the | |
93 | function, or it may update the display and continue execution while | |
94 | checking for debugging commands. The default execution mode is step, | |
95 | which stops execution. @xref{Edebug Execution Modes}. | |
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96 | |
97 | Within Edebug, you normally view an Emacs buffer showing the source of | |
98 | the Lisp code you are debugging. This is referred to as the @dfn{source | |
2bdedac1 | 99 | code buffer}, and it is temporarily read-only. |
73804d4b | 100 | |
2634c6e4 | 101 | An arrow in the left fringe indicates the line where the function is |
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102 | executing. Point initially shows where within the line the function is |
103 | executing, but this ceases to be true if you move point yourself. | |
104 | ||
105 | If you instrument the definition of @code{fac} (shown below) and then | |
8241495d RS |
106 | execute @code{(fac 3)}, here is what you would normally see. Point is |
107 | at the open-parenthesis before @code{if}. | |
73804d4b RS |
108 | |
109 | @example | |
110 | (defun fac (n) | |
111 | =>@point{}(if (< 0 n) | |
112 | (* n (fac (1- n))) | |
113 | 1)) | |
114 | @end example | |
115 | ||
116 | @cindex stop points | |
117 | The places within a function where Edebug can stop execution are called | |
118 | @dfn{stop points}. These occur both before and after each subexpression | |
177c0ea7 | 119 | that is a list, and also after each variable reference. |
8241495d | 120 | Here we use periods to show the stop points in the function |
73804d4b RS |
121 | @code{fac}: |
122 | ||
123 | @example | |
124 | (defun fac (n) | |
125 | .(if .(< 0 n.). | |
b180eac2 | 126 | .(* n. .(fac .(1- n.).).). |
73804d4b RS |
127 | 1).) |
128 | @end example | |
129 | ||
130 | The special commands of Edebug are available in the source code buffer | |
131 | in addition to the commands of Emacs Lisp mode. For example, you can | |
132 | type the Edebug command @key{SPC} to execute until the next stop point. | |
133 | If you type @key{SPC} once after entry to @code{fac}, here is the | |
134 | display you will see: | |
135 | ||
136 | @example | |
137 | (defun fac (n) | |
138 | =>(if @point{}(< 0 n) | |
139 | (* n (fac (1- n))) | |
140 | 1)) | |
141 | @end example | |
142 | ||
143 | When Edebug stops execution after an expression, it displays the | |
177c0ea7 | 144 | expression's value in the echo area. |
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145 | |
146 | Other frequently used commands are @kbd{b} to set a breakpoint at a stop | |
147 | point, @kbd{g} to execute until a breakpoint is reached, and @kbd{q} to | |
148 | exit Edebug and return to the top-level command loop. Type @kbd{?} to | |
149 | display a list of all Edebug commands. | |
150 | ||
151 | @node Instrumenting | |
152 | @subsection Instrumenting for Edebug | |
153 | ||
154 | In order to use Edebug to debug Lisp code, you must first | |
155 | @dfn{instrument} the code. Instrumenting code inserts additional code | |
87b2d5ff | 156 | into it, to invoke Edebug at the proper places. |
73804d4b RS |
157 | |
158 | @kindex C-M-x | |
159 | @findex eval-defun (Edebug) | |
2634c6e4 RS |
160 | When you invoke command @kbd{C-M-x} (@code{eval-defun}) with a |
161 | prefix argument on a function definition, it instruments the | |
162 | definition before evaluating it. (This does not modify the source | |
163 | code itself.) If the variable @code{edebug-all-defs} is | |
164 | non-@code{nil}, that inverts the meaning of the prefix argument: in | |
165 | this case, @kbd{C-M-x} instruments the definition @emph{unless} it has | |
166 | a prefix argument. The default value of @code{edebug-all-defs} is | |
167 | @code{nil}. The command @kbd{M-x edebug-all-defs} toggles the value | |
168 | of the variable @code{edebug-all-defs}. | |
73804d4b | 169 | |
969fe9b5 | 170 | @findex eval-region @r{(Edebug)} |
d8ca18c7 | 171 | @findex eval-buffer @r{(Edebug)} |
969fe9b5 | 172 | @findex eval-current-buffer @r{(Edebug)} |
73804d4b RS |
173 | If @code{edebug-all-defs} is non-@code{nil}, then the commands |
174 | @code{eval-region}, @code{eval-current-buffer}, and @code{eval-buffer} | |
175 | also instrument any definitions they evaluate. Similarly, | |
176 | @code{edebug-all-forms} controls whether @code{eval-region} should | |
177 | instrument @emph{any} form, even non-defining forms. This doesn't apply | |
178 | to loading or evaluations in the minibuffer. The command @kbd{M-x | |
179 | edebug-all-forms} toggles this option. | |
180 | ||
181 | @findex edebug-eval-top-level-form | |
969fe9b5 | 182 | Another command, @kbd{M-x edebug-eval-top-level-form}, is available to |
f9f59935 RS |
183 | instrument any top-level form regardless of the values of |
184 | @code{edebug-all-defs} and @code{edebug-all-forms}. | |
73804d4b | 185 | |
969fe9b5 | 186 | While Edebug is active, the command @kbd{I} |
73804d4b | 187 | (@code{edebug-instrument-callee}) instruments the definition of the |
da0bbbc4 | 188 | function or macro called by the list form after point, if it is not already |
73804d4b | 189 | instrumented. This is possible only if Edebug knows where to find the |
622fa380 | 190 | source for that function; for this reason, after loading Edebug, |
8241495d RS |
191 | @code{eval-region} records the position of every definition it |
192 | evaluates, even if not instrumenting it. See also the @kbd{i} command | |
193 | (@pxref{Jumping}), which steps into the call after instrumenting the | |
194 | function. | |
73804d4b | 195 | |
a9f0a989 RS |
196 | Edebug knows how to instrument all the standard special forms, |
197 | @code{interactive} forms with an expression argument, anonymous lambda | |
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198 | expressions, and other defining forms. However, Edebug cannot determine |
199 | on its own what a user-defined macro will do with the arguments of a | |
67c1390d | 200 | macro call, so you must provide that information using Edebug |
622fa380 | 201 | specifications; for details, @pxref{Edebug and Macros}. |
73804d4b | 202 | |
969fe9b5 RS |
203 | When Edebug is about to instrument code for the first time in a |
204 | session, it runs the hook @code{edebug-setup-hook}, then sets it to | |
8241495d | 205 | @code{nil}. You can use this to load Edebug specifications |
67c1390d | 206 | associated with a package you are using, but only when you use Edebug. |
969fe9b5 RS |
207 | |
208 | @findex eval-expression @r{(Edebug)} | |
a9f0a989 | 209 | To remove instrumentation from a definition, simply re-evaluate its |
73804d4b | 210 | definition in a way that does not instrument. There are two ways of |
87b2d5ff | 211 | evaluating forms that never instrument them: from a file with |
73804d4b | 212 | @code{load}, and from the minibuffer with @code{eval-expression} |
bfe721d1 | 213 | (@kbd{M-:}). |
73804d4b RS |
214 | |
215 | If Edebug detects a syntax error while instrumenting, it leaves point | |
216 | at the erroneous code and signals an @code{invalid-read-syntax} error. | |
217 | ||
218 | @xref{Edebug Eval}, for other evaluation functions available | |
219 | inside of Edebug. | |
220 | ||
221 | @node Edebug Execution Modes | |
222 | @subsection Edebug Execution Modes | |
223 | ||
224 | @cindex Edebug execution modes | |
225 | Edebug supports several execution modes for running the program you are | |
226 | debugging. We call these alternatives @dfn{Edebug execution modes}; do | |
87b2d5ff | 227 | not confuse them with major or minor modes. The current Edebug execution mode |
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228 | determines how far Edebug continues execution before stopping---whether |
229 | it stops at each stop point, or continues to the next breakpoint, for | |
230 | example---and how much Edebug displays the progress of the evaluation | |
231 | before it stops. | |
232 | ||
233 | Normally, you specify the Edebug execution mode by typing a command to | |
234 | continue the program in a certain mode. Here is a table of these | |
8241495d | 235 | commands; all except for @kbd{S} resume execution of the program, at |
73804d4b RS |
236 | least for a certain distance. |
237 | ||
238 | @table @kbd | |
239 | @item S | |
8241495d | 240 | Stop: don't execute any more of the program, but wait for more |
73804d4b RS |
241 | Edebug commands (@code{edebug-stop}). |
242 | ||
243 | @item @key{SPC} | |
244 | Step: stop at the next stop point encountered (@code{edebug-step-mode}). | |
245 | ||
246 | @item n | |
247 | Next: stop at the next stop point encountered after an expression | |
248 | (@code{edebug-next-mode}). Also see @code{edebug-forward-sexp} in | |
c5f8bf2d | 249 | @ref{Jumping}. |
73804d4b RS |
250 | |
251 | @item t | |
89f6de49 RS |
252 | Trace: pause (normally one second) at each Edebug stop point |
253 | (@code{edebug-trace-mode}). | |
73804d4b RS |
254 | |
255 | @item T | |
256 | Rapid trace: update the display at each stop point, but don't actually | |
257 | pause (@code{edebug-Trace-fast-mode}). | |
258 | ||
259 | @item g | |
260 | Go: run until the next breakpoint (@code{edebug-go-mode}). @xref{Breakpoints}. | |
261 | ||
262 | @item c | |
263 | Continue: pause one second at each breakpoint, and then continue | |
264 | (@code{edebug-continue-mode}). | |
265 | ||
266 | @item C | |
267 | Rapid continue: move point to each breakpoint, but don't pause | |
268 | (@code{edebug-Continue-fast-mode}). | |
269 | ||
270 | @item G | |
271 | Go non-stop: ignore breakpoints (@code{edebug-Go-nonstop-mode}). You | |
272 | can still stop the program by typing @kbd{S}, or any editing command. | |
273 | @end table | |
274 | ||
275 | In general, the execution modes earlier in the above list run the | |
87b2d5ff | 276 | program more slowly or stop sooner than the modes later in the list. |
73804d4b RS |
277 | |
278 | While executing or tracing, you can interrupt the execution by typing | |
279 | any Edebug command. Edebug stops the program at the next stop point and | |
87b2d5ff RS |
280 | then executes the command you typed. For example, typing @kbd{t} during |
281 | execution switches to trace mode at the next stop point. You can use | |
282 | @kbd{S} to stop execution without doing anything else. | |
73804d4b RS |
283 | |
284 | If your function happens to read input, a character you type intending | |
285 | to interrupt execution may be read by the function instead. You can | |
286 | avoid such unintended results by paying attention to when your program | |
287 | wants input. | |
288 | ||
289 | @cindex keyboard macros (Edebug) | |
290 | Keyboard macros containing the commands in this section do not | |
291 | completely work: exiting from Edebug, to resume the program, loses track | |
292 | of the keyboard macro. This is not easy to fix. Also, defining or | |
293 | executing a keyboard macro outside of Edebug does not affect commands | |
8241495d | 294 | inside Edebug. This is usually an advantage. See also the |
622fa380 | 295 | @code{edebug-continue-kbd-macro} option in @ref{Edebug Options}. |
73804d4b | 296 | |
2634c6e4 | 297 | When you enter a new Edebug level, the initial execution mode comes |
622fa380 GM |
298 | from the value of the variable @code{edebug-initial-mode} |
299 | (@pxref{Edebug Options}). By default, this specifies step mode. Note | |
2634c6e4 RS |
300 | that you may reenter the same Edebug level several times if, for |
301 | example, an instrumented function is called several times from one | |
302 | command. | |
73804d4b | 303 | |
89f6de49 RS |
304 | @defopt edebug-sit-for-seconds |
305 | This option specifies how many seconds to wait between execution steps | |
622fa380 | 306 | in trace mode or continue mode. The default is 1 second. |
b52a26fb | 307 | @end defopt |
73804d4b RS |
308 | |
309 | @node Jumping | |
310 | @subsection Jumping | |
311 | ||
312 | The commands described in this section execute until they reach a | |
313 | specified location. All except @kbd{i} make a temporary breakpoint to | |
314 | establish the place to stop, then switch to go mode. Any other | |
315 | breakpoint reached before the intended stop point will also stop | |
316 | execution. @xref{Breakpoints}, for the details on breakpoints. | |
317 | ||
318 | These commands may fail to work as expected in case of nonlocal exit, | |
8241495d RS |
319 | as that can bypass the temporary breakpoint where you expected the |
320 | program to stop. | |
73804d4b RS |
321 | |
322 | @table @kbd | |
323 | @item h | |
324 | Proceed to the stop point near where point is (@code{edebug-goto-here}). | |
325 | ||
326 | @item f | |
342fd6cd | 327 | Run the program for one expression |
73804d4b RS |
328 | (@code{edebug-forward-sexp}). |
329 | ||
330 | @item o | |
622fa380 | 331 | Run the program until the end of the containing sexp (@code{edebug-step-out}). |
73804d4b RS |
332 | |
333 | @item i | |
334 | Step into the function or macro called by the form after point. | |
335 | @end table | |
336 | ||
c5f8bf2d LT |
337 | The @kbd{h} command proceeds to the stop point at or after the current |
338 | location of point, using a temporary breakpoint. | |
73804d4b RS |
339 | |
340 | The @kbd{f} command runs the program forward over one expression. More | |
341 | precisely, it sets a temporary breakpoint at the position that | |
622fa380 GM |
342 | @code{forward-sexp} would reach, then executes in go mode so that |
343 | the program will stop at breakpoints. | |
73804d4b RS |
344 | |
345 | With a prefix argument @var{n}, the temporary breakpoint is placed | |
346 | @var{n} sexps beyond point. If the containing list ends before @var{n} | |
347 | more elements, then the place to stop is after the containing | |
348 | expression. | |
349 | ||
622fa380 GM |
350 | You must check that the position @code{forward-sexp} finds is a place |
351 | that the program will really get to. In @code{cond}, for example, | |
352 | this may not be true. | |
73804d4b | 353 | |
8241495d RS |
354 | For flexibility, the @kbd{f} command does @code{forward-sexp} starting |
355 | at point, rather than at the stop point. If you want to execute one | |
622fa380 GM |
356 | expression @emph{from the current stop point}, first type @kbd{w} |
357 | (@code{edebug-where}) to move point there, and then type @kbd{f}. | |
73804d4b RS |
358 | |
359 | The @kbd{o} command continues ``out of'' an expression. It places a | |
360 | temporary breakpoint at the end of the sexp containing point. If the | |
87b2d5ff RS |
361 | containing sexp is a function definition itself, @kbd{o} continues until |
362 | just before the last sexp in the definition. If that is where you are | |
363 | now, it returns from the function and then stops. In other words, this | |
73804d4b RS |
364 | command does not exit the currently executing function unless you are |
365 | positioned after the last sexp. | |
366 | ||
367 | The @kbd{i} command steps into the function or macro called by the list | |
87b2d5ff RS |
368 | form after point, and stops at its first stop point. Note that the form |
369 | need not be the one about to be evaluated. But if the form is a | |
370 | function call about to be evaluated, remember to use this command before | |
371 | any of the arguments are evaluated, since otherwise it will be too late. | |
73804d4b RS |
372 | |
373 | The @kbd{i} command instruments the function or macro it's supposed to | |
374 | step into, if it isn't instrumented already. This is convenient, but keep | |
375 | in mind that the function or macro remains instrumented unless you explicitly | |
376 | arrange to deinstrument it. | |
377 | ||
378 | @node Edebug Misc | |
379 | @subsection Miscellaneous Edebug Commands | |
380 | ||
381 | Some miscellaneous Edebug commands are described here. | |
382 | ||
383 | @table @kbd | |
384 | @item ? | |
385 | Display the help message for Edebug (@code{edebug-help}). | |
386 | ||
387 | @item C-] | |
388 | Abort one level back to the previous command level | |
389 | (@code{abort-recursive-edit}). | |
390 | ||
391 | @item q | |
392 | Return to the top level editor command loop (@code{top-level}). This | |
393 | exits all recursive editing levels, including all levels of Edebug | |
394 | activity. However, instrumented code protected with | |
395 | @code{unwind-protect} or @code{condition-case} forms may resume | |
396 | debugging. | |
397 | ||
398 | @item Q | |
8241495d | 399 | Like @kbd{q}, but don't stop even for protected code |
622fa380 | 400 | (@code{edebug-top-level-nonstop}). |
73804d4b RS |
401 | |
402 | @item r | |
403 | Redisplay the most recently known expression result in the echo area | |
404 | (@code{edebug-previous-result}). | |
405 | ||
406 | @item d | |
407 | Display a backtrace, excluding Edebug's own functions for clarity | |
408 | (@code{edebug-backtrace}). | |
409 | ||
410 | You cannot use debugger commands in the backtrace buffer in Edebug as | |
411 | you would in the standard debugger. | |
412 | ||
413 | The backtrace buffer is killed automatically when you continue | |
414 | execution. | |
415 | @end table | |
416 | ||
8241495d RS |
417 | You can invoke commands from Edebug that activate Edebug again |
418 | recursively. Whenever Edebug is active, you can quit to the top level | |
419 | with @kbd{q} or abort one recursive edit level with @kbd{C-]}. You can | |
420 | display a backtrace of all the pending evaluations with @kbd{d}. | |
73804d4b | 421 | |
c5f8bf2d LT |
422 | @node Breaks |
423 | @subsection Breaks | |
73804d4b | 424 | |
8241495d | 425 | Edebug's step mode stops execution when the next stop point is reached. |
73804d4b RS |
426 | There are three other ways to stop Edebug execution once it has started: |
427 | breakpoints, the global break condition, and source breakpoints. | |
428 | ||
c5f8bf2d LT |
429 | @menu |
430 | * Breakpoints:: Breakpoints at stop points. | |
d24880de GM |
431 | * Global Break Condition:: Breaking on an event. |
432 | * Source Breakpoints:: Embedding breakpoints in source code. | |
c5f8bf2d LT |
433 | @end menu |
434 | ||
435 | @node Breakpoints | |
77bf576c | 436 | @subsubsection Edebug Breakpoints |
c5f8bf2d | 437 | |
77bf576c | 438 | @cindex breakpoints (Edebug) |
73804d4b | 439 | While using Edebug, you can specify @dfn{breakpoints} in the program you |
8241495d | 440 | are testing: these are places where execution should stop. You can set a |
73804d4b RS |
441 | breakpoint at any stop point, as defined in @ref{Using Edebug}. For |
442 | setting and unsetting breakpoints, the stop point that is affected is | |
443 | the first one at or after point in the source code buffer. Here are the | |
444 | Edebug commands for breakpoints: | |
445 | ||
446 | @table @kbd | |
447 | @item b | |
448 | Set a breakpoint at the stop point at or after point | |
449 | (@code{edebug-set-breakpoint}). If you use a prefix argument, the | |
8241495d RS |
450 | breakpoint is temporary---it turns off the first time it stops the |
451 | program. | |
73804d4b RS |
452 | |
453 | @item u | |
177c0ea7 | 454 | Unset the breakpoint (if any) at the stop point at or after |
73804d4b RS |
455 | point (@code{edebug-unset-breakpoint}). |
456 | ||
457 | @item x @var{condition} @key{RET} | |
458 | Set a conditional breakpoint which stops the program only if | |
342fd6cd RS |
459 | evaluating @var{condition} produces a non-@code{nil} value |
460 | (@code{edebug-set-conditional-breakpoint}). With a prefix argument, | |
461 | the breakpoint is temporary. | |
73804d4b RS |
462 | |
463 | @item B | |
9e2b495b | 464 | Move point to the next breakpoint in the current definition |
73804d4b RS |
465 | (@code{edebug-next-breakpoint}). |
466 | @end table | |
467 | ||
468 | While in Edebug, you can set a breakpoint with @kbd{b} and unset one | |
469 | with @kbd{u}. First move point to the Edebug stop point of your choice, | |
470 | then type @kbd{b} or @kbd{u} to set or unset a breakpoint there. | |
471 | Unsetting a breakpoint where none has been set has no effect. | |
472 | ||
8241495d RS |
473 | Re-evaluating or reinstrumenting a definition removes all of its |
474 | previous breakpoints. | |
73804d4b RS |
475 | |
476 | A @dfn{conditional breakpoint} tests a condition each time the program | |
477 | gets there. Any errors that occur as a result of evaluating the | |
478 | condition are ignored, as if the result were @code{nil}. To set a | |
479 | conditional breakpoint, use @kbd{x}, and specify the condition | |
480 | expression in the minibuffer. Setting a conditional breakpoint at a | |
481 | stop point that has a previously established conditional breakpoint puts | |
482 | the previous condition expression in the minibuffer so you can edit it. | |
483 | ||
484 | You can make a conditional or unconditional breakpoint | |
969fe9b5 | 485 | @dfn{temporary} by using a prefix argument with the command to set the |
73804d4b RS |
486 | breakpoint. When a temporary breakpoint stops the program, it is |
487 | automatically unset. | |
488 | ||
8241495d | 489 | Edebug always stops or pauses at a breakpoint, except when the Edebug |
73804d4b RS |
490 | mode is Go-nonstop. In that mode, it ignores breakpoints entirely. |
491 | ||
492 | To find out where your breakpoints are, use the @kbd{B} command, which | |
87b2d5ff RS |
493 | moves point to the next breakpoint following point, within the same |
494 | function, or to the first breakpoint if there are no following | |
495 | breakpoints. This command does not continue execution---it just moves | |
496 | point in the buffer. | |
73804d4b | 497 | |
73804d4b RS |
498 | @node Global Break Condition |
499 | @subsubsection Global Break Condition | |
500 | ||
501 | @cindex stopping on events | |
502 | @cindex global break condition | |
503 | A @dfn{global break condition} stops execution when a specified | |
504 | condition is satisfied, no matter where that may occur. Edebug | |
8241495d | 505 | evaluates the global break condition at every stop point; if it |
73804d4b RS |
506 | evaluates to a non-@code{nil} value, then execution stops or pauses |
507 | depending on the execution mode, as if a breakpoint had been hit. If | |
508 | evaluating the condition gets an error, execution does not stop. | |
509 | ||
510 | @findex edebug-set-global-break-condition | |
9e2b495b RS |
511 | The condition expression is stored in |
512 | @code{edebug-global-break-condition}. You can specify a new expression | |
c5f8bf2d LT |
513 | using the @kbd{X} command from the source code buffer while Edebug is |
514 | active, or using @kbd{C-x X X} from any buffer at any time, as long as | |
515 | Edebug is loaded (@code{edebug-set-global-break-condition}). | |
73804d4b RS |
516 | |
517 | The global break condition is the simplest way to find where in your | |
518 | code some event occurs, but it makes code run much more slowly. So you | |
519 | should reset the condition to @code{nil} when not using it. | |
520 | ||
521 | @node Source Breakpoints | |
522 | @subsubsection Source Breakpoints | |
523 | ||
524 | @findex edebug | |
525 | @cindex source breakpoints | |
526 | All breakpoints in a definition are forgotten each time you | |
8241495d RS |
527 | reinstrument it. If you wish to make a breakpoint that won't be |
528 | forgotten, you can write a @dfn{source breakpoint}, which is simply a | |
529 | call to the function @code{edebug} in your source code. You can, of | |
530 | course, make such a call conditional. For example, in the @code{fac} | |
531 | function, you can insert the first line as shown below, to stop when the | |
532 | argument reaches zero: | |
73804d4b RS |
533 | |
534 | @example | |
535 | (defun fac (n) | |
536 | (if (= n 0) (edebug)) | |
537 | (if (< 0 n) | |
538 | (* n (fac (1- n))) | |
539 | 1)) | |
540 | @end example | |
541 | ||
969fe9b5 | 542 | When the @code{fac} definition is instrumented and the function is |
73804d4b RS |
543 | called, the call to @code{edebug} acts as a breakpoint. Depending on |
544 | the execution mode, Edebug stops or pauses there. | |
545 | ||
969fe9b5 | 546 | If no instrumented code is being executed when @code{edebug} is called, |
73804d4b RS |
547 | that function calls @code{debug}. |
548 | @c This may not be a good idea anymore. | |
549 | ||
550 | @node Trapping Errors | |
551 | @subsection Trapping Errors | |
552 | ||
969fe9b5 RS |
553 | Emacs normally displays an error message when an error is signaled and |
554 | not handled with @code{condition-case}. While Edebug is active and | |
555 | executing instrumented code, it normally responds to all unhandled | |
556 | errors. You can customize this with the options @code{edebug-on-error} | |
557 | and @code{edebug-on-quit}; see @ref{Edebug Options}. | |
73804d4b | 558 | |
969fe9b5 | 559 | When Edebug responds to an error, it shows the last stop point |
73804d4b | 560 | encountered before the error. This may be the location of a call to a |
8241495d | 561 | function which was not instrumented, and within which the error actually |
73804d4b RS |
562 | occurred. For an unbound variable error, the last known stop point |
563 | might be quite distant from the offending variable reference. In that | |
8241495d | 564 | case, you might want to display a full backtrace (@pxref{Edebug Misc}). |
73804d4b | 565 | |
87b2d5ff | 566 | @c Edebug should be changed for the following: -- dan |
969fe9b5 | 567 | If you change @code{debug-on-error} or @code{debug-on-quit} while |
73804d4b RS |
568 | Edebug is active, these changes will be forgotten when Edebug becomes |
569 | inactive. Furthermore, during Edebug's recursive edit, these variables | |
570 | are bound to the values they had outside of Edebug. | |
571 | ||
73804d4b RS |
572 | @node Edebug Views |
573 | @subsection Edebug Views | |
574 | ||
969fe9b5 | 575 | These Edebug commands let you view aspects of the buffer and window |
a9f0a989 | 576 | status as they were before entry to Edebug. The outside window |
87b2d5ff RS |
577 | configuration is the collection of windows and contents that were in |
578 | effect outside of Edebug. | |
73804d4b RS |
579 | |
580 | @table @kbd | |
581 | @item v | |
342fd6cd RS |
582 | Switch to viewing the outside window configuration |
583 | (@code{edebug-view-outside}). Type @kbd{C-x X w} to return to Edebug. | |
73804d4b RS |
584 | |
585 | @item p | |
c5f8bf2d LT |
586 | Temporarily display the outside current buffer with point at its |
587 | outside position (@code{edebug-bounce-point}), pausing for one second | |
588 | before returning to Edebug. With a prefix argument @var{n}, pause for | |
589 | @var{n} seconds instead. | |
73804d4b RS |
590 | |
591 | @item w | |
1911e6e5 RS |
592 | Move point back to the current stop point in the source code buffer |
593 | (@code{edebug-where}). | |
594 | ||
595 | If you use this command in a different window displaying the same | |
596 | buffer, that window will be used instead to display the current | |
597 | definition in the future. | |
73804d4b RS |
598 | |
599 | @item W | |
87b2d5ff RS |
600 | @c Its function is not simply to forget the saved configuration -- dan |
601 | Toggle whether Edebug saves and restores the outside window | |
602 | configuration (@code{edebug-toggle-save-windows}). | |
603 | ||
604 | With a prefix argument, @code{W} only toggles saving and restoring of | |
605 | the selected window. To specify a window that is not displaying the | |
606 | source code buffer, you must use @kbd{C-x X W} from the global keymap. | |
73804d4b RS |
607 | @end table |
608 | ||
969fe9b5 | 609 | You can view the outside window configuration with @kbd{v} or just |
73804d4b | 610 | bounce to the point in the current buffer with @kbd{p}, even if |
c5f8bf2d LT |
611 | it is not normally displayed. |
612 | ||
613 | After moving point, you may wish to jump back to the stop point. | |
614 | You can do that with @kbd{w} from a source code buffer. You can jump | |
615 | back to the stop point in the source code buffer from any buffer using | |
616 | @kbd{C-x X w}. | |
73804d4b | 617 | |
969fe9b5 | 618 | Each time you use @kbd{W} to turn saving @emph{off}, Edebug forgets the |
87b2d5ff RS |
619 | saved outside window configuration---so that even if you turn saving |
620 | back @emph{on}, the current window configuration remains unchanged when | |
621 | you next exit Edebug (by continuing the program). However, the | |
622 | automatic redisplay of @samp{*edebug*} and @samp{*edebug-trace*} may | |
623 | conflict with the buffers you wish to see unless you have enough windows | |
624 | open. | |
73804d4b RS |
625 | |
626 | @node Edebug Eval | |
627 | @subsection Evaluation | |
628 | ||
8241495d RS |
629 | While within Edebug, you can evaluate expressions ``as if'' Edebug |
630 | were not running. Edebug tries to be invisible to the expression's | |
73804d4b | 631 | evaluation and printing. Evaluation of expressions that cause side |
8241495d RS |
632 | effects will work as expected, except for changes to data that Edebug |
633 | explicitly saves and restores. @xref{The Outside Context}, for details | |
634 | on this process. | |
73804d4b RS |
635 | |
636 | @table @kbd | |
637 | @item e @var{exp} @key{RET} | |
638 | Evaluate expression @var{exp} in the context outside of Edebug | |
639 | (@code{edebug-eval-expression}). That is, Edebug tries to minimize its | |
640 | interference with the evaluation. | |
641 | ||
bfe721d1 | 642 | @item M-: @var{exp} @key{RET} |
622fa380 GM |
643 | Evaluate expression @var{exp} in the context of Edebug itself |
644 | (@code{eval-expression}). | |
73804d4b RS |
645 | |
646 | @item C-x C-e | |
647 | Evaluate the expression before point, in the context outside of Edebug | |
648 | (@code{edebug-eval-last-sexp}). | |
649 | @end table | |
650 | ||
651 | @cindex lexical binding (Edebug) | |
969fe9b5 | 652 | Edebug supports evaluation of expressions containing references to |
73804d4b | 653 | lexically bound symbols created by the following constructs in |
622fa380 GM |
654 | @file{cl.el}: @code{lexical-let}, @code{macrolet}, and |
655 | @code{symbol-macrolet}. | |
73804d4b | 656 | |
73804d4b RS |
657 | @node Eval List |
658 | @subsection Evaluation List Buffer | |
659 | ||
969fe9b5 | 660 | You can use the @dfn{evaluation list buffer}, called @samp{*edebug*}, to |
73804d4b RS |
661 | evaluate expressions interactively. You can also set up the |
662 | @dfn{evaluation list} of expressions to be evaluated automatically each | |
663 | time Edebug updates the display. | |
664 | ||
665 | @table @kbd | |
666 | @item E | |
667 | Switch to the evaluation list buffer @samp{*edebug*} | |
668 | (@code{edebug-visit-eval-list}). | |
669 | @end table | |
670 | ||
969fe9b5 | 671 | In the @samp{*edebug*} buffer you can use the commands of Lisp |
73804d4b RS |
672 | Interaction mode (@pxref{Lisp Interaction,,, emacs, The GNU Emacs |
673 | Manual}) as well as these special commands: | |
674 | ||
675 | @table @kbd | |
969fe9b5 | 676 | @item C-j |
73804d4b RS |
677 | Evaluate the expression before point, in the outside context, and insert |
678 | the value in the buffer (@code{edebug-eval-print-last-sexp}). | |
679 | ||
680 | @item C-x C-e | |
681 | Evaluate the expression before point, in the context outside of Edebug | |
682 | (@code{edebug-eval-last-sexp}). | |
683 | ||
684 | @item C-c C-u | |
87b2d5ff | 685 | Build a new evaluation list from the contents of the buffer |
73804d4b RS |
686 | (@code{edebug-update-eval-list}). |
687 | ||
688 | @item C-c C-d | |
689 | Delete the evaluation list group that point is in | |
690 | (@code{edebug-delete-eval-item}). | |
691 | ||
692 | @item C-c C-w | |
693 | Switch back to the source code buffer at the current stop point | |
694 | (@code{edebug-where}). | |
695 | @end table | |
696 | ||
969fe9b5 RS |
697 | You can evaluate expressions in the evaluation list window with |
698 | @kbd{C-j} or @kbd{C-x C-e}, just as you would in @samp{*scratch*}; | |
73804d4b RS |
699 | but they are evaluated in the context outside of Edebug. |
700 | ||
969fe9b5 | 701 | The expressions you enter interactively (and their results) are lost |
73804d4b | 702 | when you continue execution; but you can set up an @dfn{evaluation list} |
177c0ea7 | 703 | consisting of expressions to be evaluated each time execution stops. |
73804d4b RS |
704 | |
705 | @cindex evaluation list group | |
969fe9b5 | 706 | To do this, write one or more @dfn{evaluation list groups} in the |
73804d4b RS |
707 | evaluation list buffer. An evaluation list group consists of one or |
708 | more Lisp expressions. Groups are separated by comment lines. | |
709 | ||
969fe9b5 | 710 | The command @kbd{C-c C-u} (@code{edebug-update-eval-list}) rebuilds the |
73804d4b | 711 | evaluation list, scanning the buffer and using the first expression of |
87b2d5ff RS |
712 | each group. (The idea is that the second expression of the group is the |
713 | value previously computed and displayed.) | |
73804d4b | 714 | |
969fe9b5 | 715 | Each entry to Edebug redisplays the evaluation list by inserting each |
87b2d5ff RS |
716 | expression in the buffer, followed by its current value. It also |
717 | inserts comment lines so that each expression becomes its own group. | |
718 | Thus, if you type @kbd{C-c C-u} again without changing the buffer text, | |
719 | the evaluation list is effectively unchanged. | |
73804d4b | 720 | |
622fa380 GM |
721 | If an error occurs during an evaluation from the evaluation list, |
722 | the error message is displayed in a string as if it were the result. | |
723 | Therefore, expressions using variables that are not currently valid do | |
724 | not interrupt your debugging. | |
73804d4b | 725 | |
969fe9b5 | 726 | Here is an example of what the evaluation list window looks like after |
73804d4b RS |
727 | several expressions have been added to it: |
728 | ||
729 | @smallexample | |
730 | (current-buffer) | |
731 | #<buffer *scratch*> | |
732 | ;--------------------------------------------------------------- | |
733 | (selected-window) | |
734 | #<window 16 on *scratch*> | |
735 | ;--------------------------------------------------------------- | |
736 | (point) | |
737 | 196 | |
738 | ;--------------------------------------------------------------- | |
739 | bad-var | |
740 | "Symbol's value as variable is void: bad-var" | |
741 | ;--------------------------------------------------------------- | |
742 | (recursion-depth) | |
743 | 0 | |
744 | ;--------------------------------------------------------------- | |
745 | this-command | |
746 | eval-last-sexp | |
747 | ;--------------------------------------------------------------- | |
748 | @end smallexample | |
749 | ||
750 | To delete a group, move point into it and type @kbd{C-c C-d}, or simply | |
751 | delete the text for the group and update the evaluation list with | |
752 | @kbd{C-c C-u}. To add a new expression to the evaluation list, insert | |
8241495d RS |
753 | the expression at a suitable place, insert a new comment line, then type |
754 | @kbd{C-c C-u}. You need not insert dashes in the comment line---its | |
755 | contents don't matter. | |
73804d4b RS |
756 | |
757 | After selecting @samp{*edebug*}, you can return to the source code | |
758 | buffer with @kbd{C-c C-w}. The @samp{*edebug*} buffer is killed when | |
759 | you continue execution, and recreated next time it is needed. | |
760 | ||
73804d4b RS |
761 | @node Printing in Edebug |
762 | @subsection Printing in Edebug | |
763 | ||
764 | @cindex printing (Edebug) | |
765 | @cindex printing circular structures | |
766 | @pindex cust-print | |
767 | If an expression in your program produces a value containing circular | |
768 | list structure, you may get an error when Edebug attempts to print it. | |
769 | ||
73804d4b RS |
770 | One way to cope with circular structure is to set @code{print-length} |
771 | or @code{print-level} to truncate the printing. Edebug does this for | |
622fa380 GM |
772 | you; it binds @code{print-length} and @code{print-level} to the values |
773 | of the variables @code{edebug-print-length} and | |
774 | @code{edebug-print-level} (so long as they have non-@code{nil} | |
775 | values). @xref{Output Variables}. | |
73804d4b | 776 | |
969fe9b5 | 777 | @defopt edebug-print-length |
8241495d RS |
778 | If non-@code{nil}, Edebug binds @code{print-length} to this value while |
779 | printing results. The default value is @code{50}. | |
969fe9b5 RS |
780 | @end defopt |
781 | ||
177c0ea7 | 782 | @defopt edebug-print-level |
8241495d RS |
783 | If non-@code{nil}, Edebug binds @code{print-level} to this value while |
784 | printing results. The default value is @code{50}. | |
969fe9b5 RS |
785 | @end defopt |
786 | ||
73804d4b | 787 | You can also print circular structures and structures that share |
8241495d RS |
788 | elements more informatively by binding @code{print-circle} |
789 | to a non-@code{nil} value. | |
73804d4b RS |
790 | |
791 | Here is an example of code that creates a circular structure: | |
792 | ||
793 | @example | |
794 | (setq a '(x y)) | |
a9f0a989 | 795 | (setcar a a) |
73804d4b RS |
796 | @end example |
797 | ||
798 | @noindent | |
799 | Custom printing prints this as @samp{Result: #1=(#1# y)}. The | |
800 | @samp{#1=} notation labels the structure that follows it with the label | |
a9f0a989 | 801 | @samp{1}, and the @samp{#1#} notation references the previously labeled |
73804d4b RS |
802 | structure. This notation is used for any shared elements of lists or |
803 | vectors. | |
804 | ||
177c0ea7 | 805 | @defopt edebug-print-circle |
8241495d | 806 | If non-@code{nil}, Edebug binds @code{print-circle} to this value while |
011caae1 | 807 | printing results. The default value is @code{t}. |
969fe9b5 RS |
808 | @end defopt |
809 | ||
73804d4b RS |
810 | Other programs can also use custom printing; see @file{cust-print.el} |
811 | for details. | |
812 | ||
813 | @node Trace Buffer | |
814 | @subsection Trace Buffer | |
815 | @cindex trace buffer | |
816 | ||
87b2d5ff | 817 | Edebug can record an execution trace, storing it in a buffer named |
73804d4b RS |
818 | @samp{*edebug-trace*}. This is a log of function calls and returns, |
819 | showing the function names and their arguments and values. To enable | |
820 | trace recording, set @code{edebug-trace} to a non-@code{nil} value. | |
821 | ||
822 | Making a trace buffer is not the same thing as using trace execution | |
823 | mode (@pxref{Edebug Execution Modes}). | |
824 | ||
825 | When trace recording is enabled, each function entry and exit adds | |
8241495d RS |
826 | lines to the trace buffer. A function entry record consists of |
827 | @samp{::::@{}, followed by the function name and argument values. A | |
828 | function exit record consists of @samp{::::@}}, followed by the function | |
73804d4b RS |
829 | name and result of the function. |
830 | ||
831 | The number of @samp{:}s in an entry shows its recursion depth. You | |
832 | can use the braces in the trace buffer to find the matching beginning or | |
833 | end of function calls. | |
834 | ||
835 | @findex edebug-print-trace-before | |
836 | @findex edebug-print-trace-after | |
837 | You can customize trace recording for function entry and exit by | |
838 | redefining the functions @code{edebug-print-trace-before} and | |
839 | @code{edebug-print-trace-after}. | |
840 | ||
841 | @defmac edebug-tracing string body@dots{} | |
842 | This macro requests additional trace information around the execution | |
843 | of the @var{body} forms. The argument @var{string} specifies text | |
c5f8bf2d LT |
844 | to put in the trace buffer, after the @samp{@{} or @samp{@}}. All |
845 | the arguments are evaluated, and @code{edebug-tracing} returns the | |
846 | value of the last form in @var{body}. | |
73804d4b RS |
847 | @end defmac |
848 | ||
849 | @defun edebug-trace format-string &rest format-args | |
850 | This function inserts text in the trace buffer. It computes the text | |
851 | with @code{(apply 'format @var{format-string} @var{format-args})}. | |
87b2d5ff | 852 | It also appends a newline to separate entries. |
73804d4b RS |
853 | @end defun |
854 | ||
1911e6e5 RS |
855 | @code{edebug-tracing} and @code{edebug-trace} insert lines in the |
856 | trace buffer whenever they are called, even if Edebug is not active. | |
857 | Adding text to the trace buffer also scrolls its window to show the last | |
858 | lines inserted. | |
73804d4b | 859 | |
73804d4b RS |
860 | @node Coverage Testing |
861 | @subsection Coverage Testing | |
862 | ||
77bf576c | 863 | @cindex coverage testing (Edebug) |
73804d4b RS |
864 | @cindex frequency counts |
865 | @cindex performance analysis | |
77bf576c | 866 | Edebug provides rudimentary coverage testing and display of execution |
1911e6e5 RS |
867 | frequency. |
868 | ||
869 | Coverage testing works by comparing the result of each expression with | |
870 | the previous result; each form in the program is considered ``covered'' | |
871 | if it has returned two different values since you began testing coverage | |
872 | in the current Emacs session. Thus, to do coverage testing on your | |
873 | program, execute it under various conditions and note whether it behaves | |
874 | correctly; Edebug will tell you when you have tried enough different | |
875 | conditions that each form has returned two different values. | |
876 | ||
877 | Coverage testing makes execution slower, so it is only done if | |
ebc6903b | 878 | @code{edebug-test-coverage} is non-@code{nil}. Frequency counting is |
622fa380 | 879 | performed for all executions of an instrumented function, even if the |
ebc6903b RS |
880 | execution mode is Go-nonstop, and regardless of whether coverage testing |
881 | is enabled. | |
1911e6e5 | 882 | |
89f6de49 RS |
883 | @kindex C-x X = |
884 | @findex edebug-temp-display-freq-count | |
885 | Use @kbd{C-x X =} (@code{edebug-display-freq-count}) to display both | |
886 | the coverage information and the frequency counts for a definition. | |
887 | Just @kbd{=} (@code{edebug-temp-display-freq-count}) displays the same | |
888 | information temporarily, only until you type another key. | |
73804d4b RS |
889 | |
890 | @deffn Command edebug-display-freq-count | |
891 | This command displays the frequency count data for each line of the | |
892 | current definition. | |
893 | ||
622fa380 GM |
894 | It inserts frequency counts as comment lines after each line of code. |
895 | You can undo all insertions with one @code{undo} command. The counts | |
896 | appear under the @samp{(} before an expression or the @samp{)} after | |
897 | an expression, or on the last character of a variable. To simplify | |
898 | the display, a count is not shown if it is equal to the count of an | |
899 | earlier expression on the same line. | |
73804d4b RS |
900 | |
901 | The character @samp{=} following the count for an expression says that | |
a9f0a989 | 902 | the expression has returned the same value each time it was evaluated. |
1911e6e5 | 903 | In other words, it is not yet ``covered'' for coverage testing purposes. |
73804d4b RS |
904 | |
905 | To clear the frequency count and coverage data for a definition, | |
a9f0a989 | 906 | simply reinstrument it with @code{eval-defun}. |
73804d4b RS |
907 | @end deffn |
908 | ||
909 | For example, after evaluating @code{(fac 5)} with a source | |
910 | breakpoint, and setting @code{edebug-test-coverage} to @code{t}, when | |
911 | the breakpoint is reached, the frequency data looks like this: | |
912 | ||
913 | @example | |
914 | (defun fac (n) | |
915 | (if (= n 0) (edebug)) | |
011caae1 | 916 | ;#6 1 = =5 |
73804d4b | 917 | (if (< 0 n) |
177c0ea7 | 918 | ;#5 = |
73804d4b | 919 | (* n (fac (1- n))) |
177c0ea7 | 920 | ;# 5 0 |
73804d4b | 921 | 1)) |
177c0ea7 | 922 | ;# 0 |
73804d4b RS |
923 | @end example |
924 | ||
87b2d5ff RS |
925 | The comment lines show that @code{fac} was called 6 times. The |
926 | first @code{if} statement returned 5 times with the same result each | |
73804d4b | 927 | time; the same is true of the condition on the second @code{if}. |
87b2d5ff | 928 | The recursive call of @code{fac} did not return at all. |
73804d4b RS |
929 | |
930 | ||
931 | @node The Outside Context | |
932 | @subsection The Outside Context | |
933 | ||
934 | Edebug tries to be transparent to the program you are debugging, but it | |
935 | does not succeed completely. Edebug also tries to be transparent when | |
936 | you evaluate expressions with @kbd{e} or with the evaluation list | |
937 | buffer, by temporarily restoring the outside context. This section | |
938 | explains precisely what context Edebug restores, and how Edebug fails to | |
939 | be completely transparent. | |
940 | ||
73804d4b | 941 | @menu |
d24880de GM |
942 | * Checking Whether to Stop:: When Edebug decides what to do. |
943 | * Edebug Display Update:: When Edebug updates the display. | |
944 | * Edebug Recursive Edit:: When Edebug stops execution. | |
73804d4b RS |
945 | @end menu |
946 | ||
947 | @node Checking Whether to Stop | |
948 | @subsubsection Checking Whether to Stop | |
949 | ||
87b2d5ff RS |
950 | Whenever Edebug is entered, it needs to save and restore certain data |
951 | before even deciding whether to make trace information or stop the | |
952 | program. | |
73804d4b RS |
953 | |
954 | @itemize @bullet | |
177c0ea7 | 955 | @item |
73804d4b | 956 | @code{max-lisp-eval-depth} and @code{max-specpdl-size} are both |
622fa380 GM |
957 | increased to reduce Edebug's impact on the stack. You could, however, |
958 | still run out of stack space when using Edebug. | |
73804d4b | 959 | |
177c0ea7 | 960 | @item |
73804d4b | 961 | The state of keyboard macro execution is saved and restored. While |
473671bd RS |
962 | Edebug is active, @code{executing-kbd-macro} is bound to @code{nil} |
963 | unless @code{edebug-continue-kbd-macro} is non-@code{nil}. | |
73804d4b RS |
964 | @end itemize |
965 | ||
966 | ||
967 | @node Edebug Display Update | |
968 | @subsubsection Edebug Display Update | |
969 | ||
87b2d5ff RS |
970 | @c This paragraph is not filled, because LaLiberte's conversion script |
971 | @c needs an xref to be on just one line. | |
73804d4b | 972 | When Edebug needs to display something (e.g., in trace mode), it saves |
177c0ea7 | 973 | the current window configuration from ``outside'' Edebug |
87b2d5ff RS |
974 | (@pxref{Window Configurations}). When you exit Edebug (by continuing |
975 | the program), it restores the previous window configuration. | |
73804d4b RS |
976 | |
977 | Emacs redisplays only when it pauses. Usually, when you continue | |
8241495d RS |
978 | execution, the program re-enters Edebug at a breakpoint or after |
979 | stepping, without pausing or reading input in between. In such cases, | |
73804d4b | 980 | Emacs never gets a chance to redisplay the ``outside'' configuration. |
8241495d RS |
981 | Consequently, what you see is the same window configuration as the last |
982 | time Edebug was active, with no interruption. | |
73804d4b RS |
983 | |
984 | Entry to Edebug for displaying something also saves and restores the | |
8241495d RS |
985 | following data (though some of them are deliberately not restored if an |
986 | error or quit signal occurs). | |
73804d4b RS |
987 | |
988 | @itemize @bullet | |
177c0ea7 | 989 | @item |
73804d4b RS |
990 | @cindex current buffer point and mark (Edebug) |
991 | Which buffer is current, and the positions of point and the mark in the | |
992 | current buffer, are saved and restored. | |
993 | ||
177c0ea7 | 994 | @item |
73804d4b RS |
995 | @cindex window configuration (Edebug) |
996 | The outside window configuration is saved and restored if | |
c5f8bf2d | 997 | @code{edebug-save-windows} is non-@code{nil} (@pxref{Edebug Options}). |
73804d4b RS |
998 | |
999 | The window configuration is not restored on error or quit, but the | |
1000 | outside selected window @emph{is} reselected even on error or quit in | |
1001 | case a @code{save-excursion} is active. If the value of | |
1002 | @code{edebug-save-windows} is a list, only the listed windows are saved | |
1003 | and restored. | |
1004 | ||
1005 | The window start and horizontal scrolling of the source code buffer are | |
1006 | not restored, however, so that the display remains coherent within Edebug. | |
1007 | ||
1008 | @item | |
73804d4b RS |
1009 | The value of point in each displayed buffer is saved and restored if |
1010 | @code{edebug-save-displayed-buffer-points} is non-@code{nil}. | |
1011 | ||
1012 | @item | |
1013 | The variables @code{overlay-arrow-position} and | |
622fa380 | 1014 | @code{overlay-arrow-string} are saved and restored, so you can safely |
73804d4b RS |
1015 | invoke Edebug from the recursive edit elsewhere in the same buffer. |
1016 | ||
177c0ea7 | 1017 | @item |
73804d4b RS |
1018 | @code{cursor-in-echo-area} is locally bound to @code{nil} so that |
1019 | the cursor shows up in the window. | |
1020 | @end itemize | |
1021 | ||
1022 | @node Edebug Recursive Edit | |
1023 | @subsubsection Edebug Recursive Edit | |
1024 | ||
1025 | When Edebug is entered and actually reads commands from the user, it | |
1026 | saves (and later restores) these additional data: | |
1027 | ||
1028 | @itemize @bullet | |
1029 | @item | |
1030 | The current match data. @xref{Match Data}. | |
1031 | ||
1032 | @item | |
342fd6cd | 1033 | The variables @code{last-command}, @code{this-command}, |
342fd6cd RS |
1034 | @code{last-input-event}, @code{last-command-event}, |
1035 | @code{last-event-frame}, @code{last-nonmenu-event}, and | |
1036 | @code{track-mouse}. Commands used within Edebug do not affect these | |
1037 | variables outside of Edebug. | |
73804d4b | 1038 | |
94da4eb4 RS |
1039 | Executing commands within Edebug can change the key sequence that |
1040 | would be returned by @code{this-command-keys}, and there is no way to | |
1041 | reset the key sequence from Lisp. | |
73804d4b | 1042 | |
87b2d5ff RS |
1043 | Edebug cannot save and restore the value of |
1044 | @code{unread-command-events}. Entering Edebug while this variable has a | |
1045 | nontrivial value can interfere with execution of the program you are | |
1046 | debugging. | |
1047 | ||
73804d4b RS |
1048 | @item |
1049 | Complex commands executed while in Edebug are added to the variable | |
1050 | @code{command-history}. In rare cases this can alter execution. | |
1051 | ||
1052 | @item | |
1053 | Within Edebug, the recursion depth appears one deeper than the recursion | |
1054 | depth outside Edebug. This is not true of the automatically updated | |
1055 | evaluation list window. | |
1056 | ||
1057 | @item | |
1058 | @code{standard-output} and @code{standard-input} are bound to @code{nil} | |
1059 | by the @code{recursive-edit}, but Edebug temporarily restores them during | |
1060 | evaluations. | |
1061 | ||
177c0ea7 | 1062 | @item |
73804d4b RS |
1063 | The state of keyboard macro definition is saved and restored. While |
1064 | Edebug is active, @code{defining-kbd-macro} is bound to | |
1065 | @code{edebug-continue-kbd-macro}. | |
1066 | @end itemize | |
1067 | ||
c5f8bf2d LT |
1068 | @node Edebug and Macros |
1069 | @subsection Edebug and Macros | |
1070 | ||
1071 | To make Edebug properly instrument expressions that call macros, some | |
1072 | extra care is needed. This subsection explains the details. | |
1073 | ||
1074 | @menu | |
1075 | * Instrumenting Macro Calls:: The basic problem. | |
d24880de GM |
1076 | * Specification List:: How to specify complex patterns of evaluation. |
1077 | * Backtracking:: What Edebug does when matching fails. | |
1078 | * Specification Examples:: To help understand specifications. | |
c5f8bf2d LT |
1079 | @end menu |
1080 | ||
73804d4b | 1081 | @node Instrumenting Macro Calls |
c5f8bf2d | 1082 | @subsubsection Instrumenting Macro Calls |
73804d4b | 1083 | |
969fe9b5 RS |
1084 | When Edebug instruments an expression that calls a Lisp macro, it needs |
1085 | additional information about the macro to do the job properly. This is | |
1086 | because there is no a-priori way to tell which subexpressions of the | |
1087 | macro call are forms to be evaluated. (Evaluation may occur explicitly | |
1088 | in the macro body, or when the resulting expansion is evaluated, or any | |
1089 | time later.) | |
1090 | ||
f9350c5c RS |
1091 | Therefore, you must define an Edebug specification for each macro |
1092 | that Edebug will encounter, to explain the format of calls to that | |
a7679889 | 1093 | macro. To do this, add a @code{debug} declaration to the macro |
f9350c5c RS |
1094 | definition. Here is a simple example that shows the specification for |
1095 | the @code{for} example macro (@pxref{Argument Evaluation}). | |
1096 | ||
342fd6cd | 1097 | @smallexample |
f9350c5c RS |
1098 | (defmacro for (var from init to final do &rest body) |
1099 | "Execute a simple \"for\" loop. | |
1100 | For example, (for i from 1 to 10 do (print i))." | |
af5a6df7 | 1101 | (declare (debug (symbolp "from" form "to" form "do" &rest form))) |
f9350c5c | 1102 | ...) |
342fd6cd | 1103 | @end smallexample |
f9350c5c | 1104 | |
89f6de49 | 1105 | The Edebug specification says which parts of a call to the macro are |
622fa380 | 1106 | forms to be evaluated. For simple macros, the specification |
a756468d RS |
1107 | often looks very similar to the formal argument list of the macro |
1108 | definition, but specifications are much more general than macro | |
1109 | arguments. @xref{Defining Macros}, for more explanation of | |
40d2bb40 | 1110 | the @code{declare} form. |
a756468d RS |
1111 | |
1112 | You can also define an edebug specification for a macro separately | |
f9350c5c | 1113 | from the macro definition with @code{def-edebug-spec}. Adding |
a7679889 LK |
1114 | @code{debug} declarations is preferred, and more convenient, for macro |
1115 | definitions in Lisp, but @code{def-edebug-spec} makes it possible to | |
1116 | define Edebug specifications for special forms implemented in C. | |
73804d4b RS |
1117 | |
1118 | @deffn Macro def-edebug-spec macro specification | |
1119 | Specify which expressions of a call to macro @var{macro} are forms to be | |
f9350c5c | 1120 | evaluated. @var{specification} should be the edebug specification. |
c5f8bf2d | 1121 | Neither argument is evaluated. |
73804d4b | 1122 | |
969fe9b5 | 1123 | The @var{macro} argument can actually be any symbol, not just a macro |
73804d4b RS |
1124 | name. |
1125 | @end deffn | |
1126 | ||
73804d4b RS |
1127 | Here is a table of the possibilities for @var{specification} and how each |
1128 | directs processing of arguments. | |
1129 | ||
ec221d13 | 1130 | @table @asis |
73804d4b RS |
1131 | @item @code{t} |
1132 | All arguments are instrumented for evaluation. | |
1133 | ||
1134 | @item @code{0} | |
1135 | None of the arguments is instrumented. | |
1136 | ||
1137 | @item a symbol | |
622fa380 | 1138 | The symbol must have an Edebug specification, which is used instead. |
73804d4b | 1139 | This indirection is repeated until another kind of specification is |
a9f0a989 | 1140 | found. This allows you to inherit the specification from another macro. |
73804d4b RS |
1141 | |
1142 | @item a list | |
1143 | The elements of the list describe the types of the arguments of a | |
1144 | calling form. The possible elements of a specification list are | |
1145 | described in the following sections. | |
1146 | @end table | |
1147 | ||
c5f8bf2d LT |
1148 | If a macro has no Edebug specification, neither through a @code{debug} |
1149 | declaration nor through a @code{def-edebug-spec} call, the variable | |
622fa380 GM |
1150 | @code{edebug-eval-macro-args} comes into play. |
1151 | ||
1152 | @defopt edebug-eval-macro-args | |
1153 | This controls the way Edebug treats macro arguments with no explicit | |
1154 | Edebug specification. If it is @code{nil} (the default), none of the | |
1155 | arguments is instrumented for evaluation. Otherwise, all arguments | |
1156 | are instrumented. | |
1157 | @end defopt | |
73804d4b RS |
1158 | |
1159 | @node Specification List | |
1160 | @subsubsection Specification List | |
1161 | ||
1162 | @cindex Edebug specification list | |
1163 | A @dfn{specification list} is required for an Edebug specification if | |
1164 | some arguments of a macro call are evaluated while others are not. Some | |
1165 | elements in a specification list match one or more arguments, but others | |
1166 | modify the processing of all following elements. The latter, called | |
1167 | @dfn{specification keywords}, are symbols beginning with @samp{&} (such | |
1168 | as @code{&optional}). | |
1169 | ||
1170 | A specification list may contain sublists which match arguments that are | |
1171 | themselves lists, or it may contain vectors used for grouping. Sublists | |
1172 | and groups thus subdivide the specification list into a hierarchy of | |
969fe9b5 | 1173 | levels. Specification keywords apply only to the remainder of the |
73804d4b RS |
1174 | sublist or group they are contained in. |
1175 | ||
1176 | When a specification list involves alternatives or repetition, matching | |
622fa380 GM |
1177 | it against an actual macro call may require backtracking. For more |
1178 | details, @pxref{Backtracking}. | |
73804d4b RS |
1179 | |
1180 | Edebug specifications provide the power of regular expression matching, | |
1181 | plus some context-free grammar constructs: the matching of sublists with | |
1182 | balanced parentheses, recursive processing of forms, and recursion via | |
1183 | indirect specifications. | |
1184 | ||
1185 | Here's a table of the possible elements of a specification list, with | |
67c1390d LT |
1186 | their meanings (see @ref{Specification Examples}, for the referenced |
1187 | examples): | |
73804d4b RS |
1188 | |
1189 | @table @code | |
1190 | @item sexp | |
1911e6e5 | 1191 | A single unevaluated Lisp object, which is not instrumented. |
a9f0a989 | 1192 | @c an "expression" is not necessarily intended for evaluation. |
73804d4b RS |
1193 | |
1194 | @item form | |
1195 | A single evaluated expression, which is instrumented. | |
1196 | ||
1197 | @item place | |
622fa380 GM |
1198 | @c I can't see that this index entry is useful without any explanation. |
1199 | @c @findex edebug-unwrap | |
73804d4b RS |
1200 | A place to store a value, as in the Common Lisp @code{setf} construct. |
1201 | ||
1202 | @item body | |
1203 | Short for @code{&rest form}. See @code{&rest} below. | |
1204 | ||
1205 | @item function-form | |
1206 | A function form: either a quoted function symbol, a quoted lambda | |
1207 | expression, or a form (that should evaluate to a function symbol or | |
1208 | lambda expression). This is useful when an argument that's a lambda | |
1209 | expression might be quoted with @code{quote} rather than | |
1210 | @code{function}, since it instruments the body of the lambda expression | |
1211 | either way. | |
1212 | ||
1213 | @item lambda-expr | |
1214 | A lambda expression with no quoting. | |
1215 | ||
1216 | @item &optional | |
89f6de49 | 1217 | @c @kindex &optional @r{(Edebug)} |
73804d4b | 1218 | All following elements in the specification list are optional; as soon |
177c0ea7 | 1219 | as one does not match, Edebug stops matching at this level. |
73804d4b RS |
1220 | |
1221 | To make just a few elements optional followed by non-optional elements, | |
1222 | use @code{[&optional @var{specs}@dots{}]}. To specify that several | |
1223 | elements must all match or none, use @code{&optional | |
67c1390d | 1224 | [@var{specs}@dots{}]}. See the @code{defun} example. |
73804d4b RS |
1225 | |
1226 | @item &rest | |
89f6de49 | 1227 | @c @kindex &rest @r{(Edebug)} |
73804d4b | 1228 | All following elements in the specification list are repeated zero or |
ebc6903b RS |
1229 | more times. In the last repetition, however, it is not a problem if the |
1230 | expression runs out before matching all of the elements of the | |
1231 | specification list. | |
73804d4b RS |
1232 | |
1233 | To repeat only a few elements, use @code{[&rest @var{specs}@dots{}]}. | |
1234 | To specify several elements that must all match on every repetition, use | |
1235 | @code{&rest [@var{specs}@dots{}]}. | |
1236 | ||
1237 | @item &or | |
89f6de49 | 1238 | @c @kindex &or @r{(Edebug)} |
73804d4b RS |
1239 | Each of the following elements in the specification list is an |
1240 | alternative. One of the alternatives must match, or the @code{&or} | |
1241 | specification fails. | |
1242 | ||
1243 | Each list element following @code{&or} is a single alternative. To | |
1244 | group two or more list elements as a single alternative, enclose them in | |
1245 | @code{[@dots{}]}. | |
1246 | ||
1247 | @item ¬ | |
89f6de49 | 1248 | @c @kindex ¬ @r{(Edebug)} |
73804d4b RS |
1249 | Each of the following elements is matched as alternatives as if by using |
1250 | @code{&or}, but if any of them match, the specification fails. If none | |
1251 | of them match, nothing is matched, but the @code{¬} specification | |
1252 | succeeds. | |
1253 | ||
177c0ea7 | 1254 | @item &define |
89f6de49 | 1255 | @c @kindex &define @r{(Edebug)} |
73804d4b | 1256 | Indicates that the specification is for a defining form. The defining |
a9f0a989 | 1257 | form itself is not instrumented (that is, Edebug does not stop before and |
73804d4b RS |
1258 | after the defining form), but forms inside it typically will be |
1259 | instrumented. The @code{&define} keyword should be the first element in | |
1260 | a list specification. | |
1261 | ||
1262 | @item nil | |
1263 | This is successful when there are no more arguments to match at the | |
1264 | current argument list level; otherwise it fails. See sublist | |
67c1390d | 1265 | specifications and the backquote example. |
73804d4b RS |
1266 | |
1267 | @item gate | |
1268 | @cindex preventing backtracking | |
1269 | No argument is matched but backtracking through the gate is disabled | |
1270 | while matching the remainder of the specifications at this level. This | |
1271 | is primarily used to generate more specific syntax error messages. See | |
67c1390d | 1272 | @ref{Backtracking}, for more details. Also see the @code{let} example. |
73804d4b RS |
1273 | |
1274 | @item @var{other-symbol} | |
1275 | @cindex indirect specifications | |
1276 | Any other symbol in a specification list may be a predicate or an | |
1277 | indirect specification. | |
1278 | ||
1279 | If the symbol has an Edebug specification, this @dfn{indirect | |
1280 | specification} should be either a list specification that is used in | |
1281 | place of the symbol, or a function that is called to process the | |
1282 | arguments. The specification may be defined with @code{def-edebug-spec} | |
622fa380 | 1283 | just as for macros. See the @code{defun} example. |
73804d4b RS |
1284 | |
1285 | Otherwise, the symbol should be a predicate. The predicate is called | |
1286 | with the argument and the specification fails if the predicate returns | |
622fa380 | 1287 | @code{nil}, and the argument is not instrumented. |
73804d4b | 1288 | |
73804d4b RS |
1289 | Some suitable predicates include @code{symbolp}, @code{integerp}, |
1290 | @code{stringp}, @code{vectorp}, and @code{atom}. | |
73804d4b RS |
1291 | |
1292 | @item [@var{elements}@dots{}] | |
1293 | @cindex [@dots{}] (Edebug) | |
1294 | A vector of elements groups the elements into a single @dfn{group | |
1295 | specification}. Its meaning has nothing to do with vectors. | |
1296 | ||
1297 | @item "@var{string}" | |
1298 | The argument should be a symbol named @var{string}. This specification | |
1299 | is equivalent to the quoted symbol, @code{'@var{symbol}}, where the name | |
1300 | of @var{symbol} is the @var{string}, but the string form is preferred. | |
1301 | ||
73804d4b RS |
1302 | @item (vector @var{elements}@dots{}) |
1303 | The argument should be a vector whose elements must match the | |
67c1390d | 1304 | @var{elements} in the specification. See the backquote example. |
73804d4b RS |
1305 | |
1306 | @item (@var{elements}@dots{}) | |
1307 | Any other list is a @dfn{sublist specification} and the argument must be | |
1308 | a list whose elements match the specification @var{elements}. | |
1309 | ||
1310 | @cindex dotted lists (Edebug) | |
1311 | A sublist specification may be a dotted list and the corresponding list | |
1312 | argument may then be a dotted list. Alternatively, the last @sc{cdr} of a | |
1313 | dotted list specification may be another sublist specification (via a | |
a9f0a989 | 1314 | grouping or an indirect specification, e.g., @code{(spec . [(more |
73804d4b RS |
1315 | specs@dots{})])}) whose elements match the non-dotted list arguments. |
1316 | This is useful in recursive specifications such as in the backquote | |
67c1390d | 1317 | example. Also see the description of a @code{nil} specification |
73804d4b RS |
1318 | above for terminating such recursion. |
1319 | ||
87b2d5ff RS |
1320 | Note that a sublist specification written as @code{(specs . nil)} |
1321 | is equivalent to @code{(specs)}, and @code{(specs . | |
1322 | (sublist-elements@dots{}))} is equivalent to @code{(specs | |
73804d4b RS |
1323 | sublist-elements@dots{})}. |
1324 | @end table | |
1325 | ||
1326 | @c Need to document extensions with &symbol and :symbol | |
1327 | ||
969fe9b5 | 1328 | Here is a list of additional specifications that may appear only after |
67c1390d | 1329 | @code{&define}. See the @code{defun} example. |
73804d4b RS |
1330 | |
1331 | @table @code | |
1332 | @item name | |
177c0ea7 | 1333 | The argument, a symbol, is the name of the defining form. |
73804d4b RS |
1334 | |
1335 | A defining form is not required to have a name field; and it may have | |
1336 | multiple name fields. | |
1337 | ||
1338 | @item :name | |
1339 | This construct does not actually match an argument. The element | |
1340 | following @code{:name} should be a symbol; it is used as an additional | |
1341 | name component for the definition. You can use this to add a unique, | |
1342 | static component to the name of the definition. It may be used more | |
1343 | than once. | |
1344 | ||
1345 | @item arg | |
1346 | The argument, a symbol, is the name of an argument of the defining form. | |
a9f0a989 | 1347 | However, lambda-list keywords (symbols starting with @samp{&}) |
87b2d5ff | 1348 | are not allowed. |
73804d4b RS |
1349 | |
1350 | @item lambda-list | |
1351 | @cindex lambda-list (Edebug) | |
1352 | This matches a lambda list---the argument list of a lambda expression. | |
73804d4b RS |
1353 | |
1354 | @item def-body | |
1355 | The argument is the body of code in a definition. This is like | |
1356 | @code{body}, described above, but a definition body must be instrumented | |
1357 | with a different Edebug call that looks up information associated with | |
1358 | the definition. Use @code{def-body} for the highest level list of forms | |
1359 | within the definition. | |
1360 | ||
1361 | @item def-form | |
1362 | The argument is a single, highest-level form in a definition. This is | |
622fa380 | 1363 | like @code{def-body}, except it is used to match a single form rather than |
73804d4b RS |
1364 | a list of forms. As a special case, @code{def-form} also means that |
1365 | tracing information is not output when the form is executed. See the | |
67c1390d | 1366 | @code{interactive} example. |
73804d4b RS |
1367 | @end table |
1368 | ||
1369 | @node Backtracking | |
969fe9b5 | 1370 | @subsubsection Backtracking in Specifications |
73804d4b RS |
1371 | |
1372 | @cindex backtracking | |
1373 | @cindex syntax error (Edebug) | |
1374 | If a specification fails to match at some point, this does not | |
1375 | necessarily mean a syntax error will be signaled; instead, | |
1376 | @dfn{backtracking} will take place until all alternatives have been | |
1377 | exhausted. Eventually every element of the argument list must be | |
1378 | matched by some element in the specification, and every required element | |
1379 | in the specification must match some argument. | |
177c0ea7 | 1380 | |
a9f0a989 | 1381 | When a syntax error is detected, it might not be reported until much |
622fa380 | 1382 | later, after higher-level alternatives have been exhausted, and with the |
a9f0a989 RS |
1383 | point positioned further from the real error. But if backtracking is |
1384 | disabled when an error occurs, it can be reported immediately. Note | |
1385 | that backtracking is also reenabled automatically in several situations; | |
622fa380 GM |
1386 | when a new alternative is established by @code{&optional}, |
1387 | @code{&rest}, or @code{&or}, or at the start of processing a sublist, | |
1388 | group, or indirect specification. The effect of enabling or disabling | |
1389 | backtracking is limited to the remainder of the level currently being | |
1390 | processed and lower levels. | |
a9f0a989 RS |
1391 | |
1392 | Backtracking is disabled while matching any of the | |
1393 | form specifications (that is, @code{form}, @code{body}, @code{def-form}, and | |
73804d4b RS |
1394 | @code{def-body}). These specifications will match any form so any error |
1395 | must be in the form itself rather than at a higher level. | |
1396 | ||
a9f0a989 | 1397 | Backtracking is also disabled after successfully matching a quoted |
73804d4b | 1398 | symbol or string specification, since this usually indicates a |
a9f0a989 | 1399 | recognized construct. But if you have a set of alternative constructs that |
73804d4b RS |
1400 | all begin with the same symbol, you can usually work around this |
1401 | constraint by factoring the symbol out of the alternatives, e.g., | |
1402 | @code{["foo" &or [first case] [second case] ...]}. | |
1403 | ||
3e7274ae | 1404 | Most needs are satisfied by these two ways that backtracking is |
a9f0a989 RS |
1405 | automatically disabled, but occasionally it is useful to explicitly |
1406 | disable backtracking by using the @code{gate} specification. This is | |
1407 | useful when you know that no higher alternatives could apply. See the | |
1408 | example of the @code{let} specification. | |
73804d4b | 1409 | |
73804d4b RS |
1410 | @node Specification Examples |
1411 | @subsubsection Specification Examples | |
1412 | ||
1413 | It may be easier to understand Edebug specifications by studying | |
1414 | the examples provided here. | |
1415 | ||
1416 | A @code{let} special form has a sequence of bindings and a body. Each | |
1417 | of the bindings is either a symbol or a sublist with a symbol and | |
a9f0a989 | 1418 | optional expression. In the specification below, notice the @code{gate} |
73804d4b RS |
1419 | inside of the sublist to prevent backtracking once a sublist is found. |
1420 | ||
622fa380 | 1421 | @c FIXME? The actual definition in edebug.el does not have a gate. |
73804d4b RS |
1422 | @example |
1423 | (def-edebug-spec let | |
1424 | ((&rest | |
1425 | &or symbolp (gate symbolp &optional form)) | |
1426 | body)) | |
1427 | @end example | |
1428 | ||
622fa380 GM |
1429 | Edebug uses the following specifications for @code{defun} and the |
1430 | associated argument list and @code{interactive} specifications. It is | |
1431 | necessary to handle interactive forms specially since an expression | |
1432 | argument is actually evaluated outside of the function body. (The | |
1433 | specification for @code{defmacro} is very similar to that for | |
1434 | @code{defun}, but allows for the @code{declare} statement.) | |
73804d4b | 1435 | |
87b2d5ff | 1436 | @smallexample |
177c0ea7 JB |
1437 | (def-edebug-spec defun |
1438 | (&define name lambda-list | |
87b2d5ff | 1439 | [&optional stringp] ; @r{Match the doc string, if present.} |
73804d4b RS |
1440 | [&optional ("interactive" interactive)] |
1441 | def-body)) | |
1442 | ||
1443 | (def-edebug-spec lambda-list | |
1444 | (([&rest arg] | |
1445 | [&optional ["&optional" arg &rest arg]] | |
1446 | &optional ["&rest" arg] | |
1447 | ))) | |
1448 | ||
1449 | (def-edebug-spec interactive | |
1450 | (&optional &or stringp def-form)) ; @r{Notice: @code{def-form}} | |
87b2d5ff | 1451 | @end smallexample |
73804d4b RS |
1452 | |
1453 | The specification for backquote below illustrates how to match | |
1454 | dotted lists and use @code{nil} to terminate recursion. It also | |
1455 | illustrates how components of a vector may be matched. (The actual | |
622fa380 GM |
1456 | specification defined by Edebug is a little different, and does not |
1457 | support dotted lists because doing so causes very deep recursion that | |
1458 | could fail.) | |
73804d4b | 1459 | |
87b2d5ff | 1460 | @smallexample |
622fa380 | 1461 | (def-edebug-spec \` (backquote-form)) ; @r{Alias just for clarity.} |
73804d4b RS |
1462 | |
1463 | (def-edebug-spec backquote-form | |
1464 | (&or ([&or "," ",@@"] &or ("quote" backquote-form) form) | |
1465 | (backquote-form . [&or nil backquote-form]) | |
1466 | (vector &rest backquote-form) | |
1467 | sexp)) | |
87b2d5ff | 1468 | @end smallexample |
73804d4b RS |
1469 | |
1470 | ||
1471 | @node Edebug Options | |
1472 | @subsection Edebug Options | |
1473 | ||
1474 | These options affect the behavior of Edebug: | |
622fa380 GM |
1475 | @c Previously defopt'd: |
1476 | @c edebug-sit-for-seconds, edebug-print-length, edebug-print-level | |
1477 | @c edebug-print-circle, edebug-eval-macro-args | |
73804d4b RS |
1478 | |
1479 | @defopt edebug-setup-hook | |
1480 | Functions to call before Edebug is used. Each time it is set to a new | |
1481 | value, Edebug will call those functions once and then | |
1482 | @code{edebug-setup-hook} is reset to @code{nil}. You could use this to | |
1483 | load up Edebug specifications associated with a package you are using | |
1484 | but only when you also use Edebug. | |
1485 | @xref{Instrumenting}. | |
1486 | @end defopt | |
1487 | ||
1488 | @defopt edebug-all-defs | |
1489 | If this is non-@code{nil}, normal evaluation of defining forms such as | |
1490 | @code{defun} and @code{defmacro} instruments them for Edebug. This | |
87b2d5ff RS |
1491 | applies to @code{eval-defun}, @code{eval-region}, @code{eval-buffer}, |
1492 | and @code{eval-current-buffer}. | |
1493 | ||
1494 | Use the command @kbd{M-x edebug-all-defs} to toggle the value of this | |
1495 | option. @xref{Instrumenting}. | |
73804d4b RS |
1496 | @end defopt |
1497 | ||
1498 | @defopt edebug-all-forms | |
87b2d5ff RS |
1499 | If this is non-@code{nil}, the commands @code{eval-defun}, |
1500 | @code{eval-region}, @code{eval-buffer}, and @code{eval-current-buffer} | |
1501 | instrument all forms, even those that don't define anything. | |
1502 | This doesn't apply to loading or evaluations in the minibuffer. | |
73804d4b RS |
1503 | |
1504 | Use the command @kbd{M-x edebug-all-forms} to toggle the value of this | |
87b2d5ff | 1505 | option. @xref{Instrumenting}. |
73804d4b RS |
1506 | @end defopt |
1507 | ||
1508 | @defopt edebug-save-windows | |
1509 | If this is non-@code{nil}, Edebug saves and restores the window | |
1510 | configuration. That takes some time, so if your program does not care | |
1511 | what happens to the window configurations, it is better to set this | |
1512 | variable to @code{nil}. | |
1513 | ||
1514 | If the value is a list, only the listed windows are saved and | |
177c0ea7 | 1515 | restored. |
73804d4b RS |
1516 | |
1517 | You can use the @kbd{W} command in Edebug to change this variable | |
1518 | interactively. @xref{Edebug Display Update}. | |
1519 | @end defopt | |
1520 | ||
1521 | @defopt edebug-save-displayed-buffer-points | |
87b2d5ff RS |
1522 | If this is non-@code{nil}, Edebug saves and restores point in all |
1523 | displayed buffers. | |
73804d4b RS |
1524 | |
1525 | Saving and restoring point in other buffers is necessary if you are | |
622fa380 | 1526 | debugging code that changes the point of a buffer that is displayed in |
73804d4b | 1527 | a non-selected window. If Edebug or the user then selects the window, |
87b2d5ff | 1528 | point in that buffer will move to the window's value of point. |
73804d4b RS |
1529 | |
1530 | Saving and restoring point in all buffers is expensive, since it | |
1531 | requires selecting each window twice, so enable this only if you need | |
1532 | it. @xref{Edebug Display Update}. | |
1533 | @end defopt | |
1534 | ||
1535 | @defopt edebug-initial-mode | |
1536 | If this variable is non-@code{nil}, it specifies the initial execution | |
1537 | mode for Edebug when it is first activated. Possible values are | |
1538 | @code{step}, @code{next}, @code{go}, @code{Go-nonstop}, @code{trace}, | |
1539 | @code{Trace-fast}, @code{continue}, and @code{Continue-fast}. | |
1540 | ||
177c0ea7 | 1541 | The default value is @code{step}. |
73804d4b RS |
1542 | @xref{Edebug Execution Modes}. |
1543 | @end defopt | |
1544 | ||
1545 | @defopt edebug-trace | |
42995636 | 1546 | If this is non-@code{nil}, trace each function entry and exit. |
73804d4b | 1547 | Tracing output is displayed in a buffer named @samp{*edebug-trace*}, one |
177c0ea7 | 1548 | function entry or exit per line, indented by the recursion level. |
73804d4b | 1549 | |
a9f0a989 | 1550 | Also see @code{edebug-tracing}, in @ref{Trace Buffer}. |
73804d4b RS |
1551 | @end defopt |
1552 | ||
177c0ea7 | 1553 | @defopt edebug-test-coverage |
73804d4b | 1554 | If non-@code{nil}, Edebug tests coverage of all expressions debugged. |
73804d4b RS |
1555 | @xref{Coverage Testing}. |
1556 | @end defopt | |
1557 | ||
177c0ea7 | 1558 | @defopt edebug-continue-kbd-macro |
73804d4b RS |
1559 | If non-@code{nil}, continue defining or executing any keyboard macro |
1560 | that is executing outside of Edebug. Use this with caution since it is not | |
1561 | debugged. | |
1562 | @xref{Edebug Execution Modes}. | |
1563 | @end defopt | |
1564 | ||
622fa380 GM |
1565 | @c FIXME edebug-unwrap-results |
1566 | ||
73804d4b RS |
1567 | @defopt edebug-on-error |
1568 | Edebug binds @code{debug-on-error} to this value, if | |
1569 | @code{debug-on-error} was previously @code{nil}. @xref{Trapping | |
1570 | Errors}. | |
1571 | @end defopt | |
1572 | ||
1573 | @defopt edebug-on-quit | |
1574 | Edebug binds @code{debug-on-quit} to this value, if | |
1575 | @code{debug-on-quit} was previously @code{nil}. @xref{Trapping | |
1576 | Errors}. | |
1577 | @end defopt | |
1578 | ||
1579 | If you change the values of @code{edebug-on-error} or | |
1580 | @code{edebug-on-quit} while Edebug is active, their values won't be used | |
87b2d5ff RS |
1581 | until the @emph{next} time Edebug is invoked via a new command. |
1582 | @c Not necessarily a deeper command level. | |
1583 | @c A new command is not precisely true, but that is close enough -- dan | |
73804d4b RS |
1584 | |
1585 | @defopt edebug-global-break-condition | |
9a8dc0d3 RS |
1586 | If non-@code{nil}, an expression to test for at every stop point. If |
1587 | the result is non-@code{nil}, then break. Errors are ignored. | |
73804d4b RS |
1588 | @xref{Global Break Condition}. |
1589 | @end defopt |