Mercurial > hg > xemacs-beta
annotate man/lispref/edebug-inc.texi @ 5167:e374ea766cc1
clean up, rearrange allocation statistics code
-------------------- ChangeLog entries follow: --------------------
src/ChangeLog addition:
2010-03-21 Ben Wing <ben@xemacs.org>
* alloc.c:
* alloc.c (assert_proper_sizing):
* alloc.c (c_readonly):
* alloc.c (malloced_storage_size):
* alloc.c (fixed_type_block_overhead):
* alloc.c (lisp_object_storage_size):
* alloc.c (inc_lrecord_stats):
* alloc.c (dec_lrecord_stats):
* alloc.c (pluralize_word):
* alloc.c (object_memory_usage_stats):
* alloc.c (Fobject_memory_usage):
* alloc.c (compute_memusage_stats_length):
* alloc.c (disksave_object_finalization_1):
* alloc.c (Fgarbage_collect):
* mc-alloc.c:
* mc-alloc.c (mc_alloced_storage_size):
* mc-alloc.h:
No functionality change here. Collect the allocations-statistics
code that was scattered throughout alloc.c into one place. Add
remaining section headings so that all sections have headings
clearly identifying the start of the section and its purpose.
Expose mc_alloced_storage_size() even when not MEMORY_USAGE_STATS;
this fixes build problems and is related to the export of
lisp_object_storage_size() and malloced_storage_size() when
non-MEMORY_USAGE_STATS in the previous change set.
| author | Ben Wing <ben@xemacs.org> |
|---|---|
| date | Sun, 21 Mar 2010 04:41:49 -0500 |
| parents | 755ae5b97edb |
| children | d11efddf3617 |
| rev | line source |
|---|---|
| 428 | 1 @comment -*-texinfo-*- |
| 2 | |
| 3 @node Edebug, , Compilation Errors, Top | |
| 4 @section Edebug | |
| 5 @cindex Edebug mode | |
| 6 | |
| 7 @cindex Edebug | |
| 8 Edebug is a source-level debugger for XEmacs Lisp programs that | |
| 9 provides the following features: | |
| 10 | |
| 11 @itemize @bullet | |
| 12 @item | |
| 13 Step through evaluation, stopping before and after each expression. | |
| 14 | |
| 15 @item | |
| 16 Set conditional or unconditional breakpoints, install embedded | |
| 17 breakpoints, or a global break event. | |
| 18 | |
| 19 @item | |
| 20 Trace slow or fast stopping briefly at each stop point, or | |
| 21 each breakpoint. | |
| 22 | |
| 23 @item | |
| 24 Display expression results and evaluate expressions as if outside of | |
| 444 | 25 Edebug. Interface with the custom printing package |
| 428 | 26 for printing circular structures. |
| 27 | |
| 444 | 28 @item |
| 428 | 29 Automatically reevaluate a list of expressions and |
| 30 display their results each time Edebug updates the display. | |
| 31 | |
| 32 @item | |
| 33 Output trace info on function enter and exit. | |
| 34 | |
| 35 @item | |
| 36 Errors stop before the source causing the error. | |
| 37 | |
| 38 @item | |
| 39 Display backtrace without Edebug calls. | |
| 40 | |
| 41 @item | |
| 42 Allow specification of argument evaluation for macros and defining forms. | |
| 43 | |
| 44 @item | |
| 45 Provide rudimentary coverage testing and display of frequency counts. | |
| 46 | |
| 47 @end itemize | |
| 48 | |
| 49 The first three sections should tell you enough about Edebug to enable | |
| 50 you to use it. | |
| 51 | |
| 52 @menu | |
| 53 * Using Edebug:: Introduction to use of Edebug. | |
| 54 * Instrumenting:: You must first instrument code. | |
| 55 * Edebug Execution Modes:: Execution modes, stopping more or less often. | |
| 56 * Jumping:: Commands to jump to a specified place. | |
| 57 * Edebug Misc:: Miscellaneous commands. | |
| 58 * Breakpoints:: Setting breakpoints to make the program stop. | |
| 59 * Trapping Errors:: trapping errors with Edebug. | |
| 60 * Edebug Views:: Views inside and outside of Edebug. | |
| 61 * Edebug Eval:: Evaluating expressions within Edebug. | |
| 62 * Eval List:: Automatic expression evaluation. | |
| 63 * Reading in Edebug:: Customization of reading. | |
| 64 * Printing in Edebug:: Customization of printing. | |
| 65 * Tracing:: How to produce tracing output. | |
| 66 * Coverage Testing:: How to test evaluation coverage. | |
| 67 * The Outside Context:: Data that Edebug saves and restores. | |
| 68 * Instrumenting Macro Calls:: Specifying how to handle macro calls. | |
| 69 * Edebug Options:: Option variables for customizing Edebug. | |
| 70 @end menu | |
| 71 | |
| 72 @node Using Edebug | |
| 73 @subsection Using Edebug | |
| 74 | |
| 75 To debug an XEmacs Lisp program with Edebug, you must first | |
| 76 @dfn{instrument} the Lisp code that you want to debug. If you want to | |
| 77 just try it now, load @file{edebug.el}, move point into a definition and | |
| 78 do @kbd{C-u C-M-x} (@code{eval-defun} with a prefix argument). | |
| 79 See @ref{Instrumenting} for alternative ways to instrument code. | |
| 80 | |
| 81 Once a function is instrumented, any call to the function activates | |
| 82 Edebug. Activating Edebug may stop execution and let you step through | |
| 83 the function, or it may update the display and continue execution while | |
| 84 checking for debugging commands, depending on the selected Edebug | |
| 85 execution mode. The initial execution mode is @code{step}, by default, | |
| 86 which does stop execution. @xref{Edebug Execution Modes}. | |
| 87 | |
| 88 Within Edebug, you normally view an XEmacs buffer showing the source of | |
| 89 the Lisp function you are debugging. This is referred to as the | |
| 90 @dfn{source code buffer}---but note that it is not always the same | |
| 91 buffer depending on which function is currently being executed. | |
| 92 | |
| 93 An arrow at the left margin indicates the line where the function is | |
| 94 executing. Point initially shows where within the line the function is | |
| 95 executing, but you can move point yourself. | |
| 96 | |
| 97 If you instrument the definition of @code{fac} (shown below) and then | |
| 98 execute @code{(fac 3)}, here is what you normally see. Point is at the | |
| 99 open-parenthesis before @code{if}. | |
| 100 | |
| 101 @example | |
| 102 (defun fac (n) | |
| 103 =>@point{}(if (< 0 n) | |
| 104 (* n (fac (1- n))) | |
| 105 1)) | |
| 106 @end example | |
| 107 | |
| 108 @cindex stop points | |
| 109 The places within a function where Edebug can stop execution are called | |
| 110 @dfn{stop points}. These occur both before and after each subexpression | |
| 444 | 111 that is a list, and also after each variable reference. |
| 428 | 112 Here we show with periods the stop points found in the function |
| 113 @code{fac}: | |
| 114 | |
| 115 @example | |
| 116 (defun fac (n) | |
| 117 .(if .(< 0 n.). | |
| 118 .(* n. .(fac (1- n.).).). | |
| 119 1).) | |
| 120 @end example | |
| 121 | |
| 122 While the source code buffer is selected, the special commands of Edebug | |
| 123 are available in it, in addition to the commands of XEmacs Lisp mode. | |
| 124 (The buffer is temporarily made read-only, however.) For example, you | |
| 125 can type the Edebug command @key{SPC} to execute until the next stop | |
| 126 point. If you type @key{SPC} once after entry to @code{fac}, here is | |
| 127 the display you will see: | |
| 128 | |
| 129 @example | |
| 130 (defun fac (n) | |
| 131 =>(if @point{}(< 0 n) | |
| 132 (* n (fac (1- n))) | |
| 133 1)) | |
| 134 @end example | |
| 135 | |
| 136 When Edebug stops execution after an expression, it displays the | |
| 444 | 137 expression's value in the echo area. |
| 428 | 138 |
| 139 Other frequently used commands are @kbd{b} to set a breakpoint at a stop | |
| 140 point, @kbd{g} to execute until a breakpoint is reached, and @kbd{q} to | |
| 141 exit to the top-level command loop. Type @kbd{?} to display a list of | |
| 142 all Edebug commands. | |
| 143 | |
| 144 | |
| 145 @node Instrumenting | |
| 146 @subsection Instrumenting for Edebug | |
| 147 | |
| 148 In order to use Edebug to debug Lisp code, you must first | |
| 149 @dfn{instrument} the code. Instrumenting a form inserts additional code | |
| 150 into it which invokes Edebug at the proper places. Furthermore, if | |
| 151 Edebug detects a syntax error while instrumenting, point is left at the | |
| 152 erroneous code and an @code{invalid-read-syntax} error is signaled. | |
| 153 | |
| 154 @kindex C-M-x | |
| 155 @findex eval-defun (Edebug) | |
| 156 @findex edebug-all-defs | |
| 157 Once you have loaded Edebug, the command @kbd{C-M-x} | |
| 158 (@code{eval-defun}) is redefined so that when invoked with a prefix | |
| 159 argument on a definition, it instruments the definition before | |
| 160 evaluating it. (The source code itself is not modified.) If the | |
| 161 variable @code{edebug-all-defs} is non-@code{nil}, that inverts the | |
| 162 meaning of the prefix argument: then @kbd{C-M-x} instruments the | |
| 163 definition @emph{unless} it has a prefix argument. The default value of | |
| 164 @code{edebug-all-defs} is @code{nil}. The command @kbd{M-x | |
| 165 edebug-all-defs} toggles the value of the variable | |
| 166 @code{edebug-all-defs}. | |
| 167 | |
| 168 @findex edebug-all-forms | |
| 169 @findex eval-region (Edebug) | |
| 170 @findex eval-current-buffer (Edebug) | |
| 171 If @code{edebug-all-defs} is non-@code{nil}, then the commands | |
| 172 @code{eval-region}, @code{eval-current-buffer}, and @code{eval-buffer} | |
| 173 also instrument any definitions they evaluate. Similarly, | |
| 174 @code{edebug-all-forms} controls whether @code{eval-region} should | |
| 175 instrument @emph{any} form, even non-defining forms. This doesn't apply | |
| 176 to loading or evaluations in the minibuffer. The command @kbd{M-x | |
| 177 edebug-all-forms} toggles this option. | |
| 178 | |
| 179 @findex edebug-eval-top-level-form | |
| 180 Another command, @kbd{M-x edebug-eval-top-level-form}, is available to | |
| 181 instrument any top-level form regardless of the value of | |
| 182 @code{edebug-all-defs} or @code{edebug-all-forms}. | |
| 183 | |
| 184 Just before Edebug instruments any code, it calls any functions in the | |
| 185 variable @code{edebug-setup-hook} and resets its value to @code{nil}. | |
| 186 You could use this to load up Edebug specifications associated with a | |
| 187 package you are using but only when you also use Edebug. For example, | |
| 188 @file{my-specs.el} may be loaded automatically when you use | |
| 189 @code{my-package} with Edebug by including the following code in | |
| 190 @file{my-package.el}. | |
| 191 | |
| 192 @example | |
| 444 | 193 (add-hook 'edebug-setup-hook |
| 428 | 194 (function (lambda () (require 'my-specs)))) |
| 195 @end example | |
| 196 | |
| 197 While Edebug is active, the command @kbd{I} | |
| 198 (@code{edebug-instrument-callee}) instruments the definition of the | |
| 199 function or macro called by the list form after point, if is not already | |
| 200 instrumented. If the location of the definition is not known to Edebug, | |
| 201 this command cannot be used. After loading Edebug, @code{eval-region} | |
| 202 records the position of every definition it evaluates, even if not | |
| 203 instrumenting it. Also see the command @kbd{i} (@ref{Jumping}) which | |
| 204 steps into the callee. | |
| 205 | |
|
4905
755ae5b97edb
Change "special form" to "special operator" in our sources.
Aidan Kehoe <kehoea@parhasard.net>
parents:
444
diff
changeset
|
206 @cindex special operators (Edebug) |
| 428 | 207 @cindex interactive commands (Edebug) |
| 208 @cindex anonymous lambda expressions (Edebug) | |
| 209 @cindex Common Lisp (Edebug) | |
| 210 @pindex cl.el (Edebug) | |
| 211 @pindex cl-specs.el | |
|
4905
755ae5b97edb
Change "special form" to "special operator" in our sources.
Aidan Kehoe <kehoea@parhasard.net>
parents:
444
diff
changeset
|
212 Edebug knows how to instrument all the standard special operators, an |
| 428 | 213 interactive form with an expression argument, anonymous lambda |
| 214 expressions, and other defining forms. (Specifications for macros | |
| 215 defined by @file{cl.el} (version 2.03) are provided in | |
| 216 @file{cl-specs.el}.) Edebug cannot know what a user-defined macro will | |
| 217 do with the arguments of a macro call so you must tell it. See | |
| 218 @ref{Instrumenting Macro Calls} for the details. | |
| 219 | |
| 220 @findex eval-expression (Edebug) | |
| 221 Note that a couple ways remain to evaluate expressions without | |
| 222 instrumenting them. Loading a file via the @code{load} subroutine does | |
| 223 not instrument expressions for Edebug. Evaluations in the minibuffer | |
| 224 via @code{eval-expression} (@kbd{M-ESC}) are not instrumented. | |
| 225 | |
| 226 To remove instrumentation from a definition, simply reevaluate it with | |
| 227 one of the non-instrumenting commands, or reload the file. | |
| 228 | |
| 229 See @ref{Edebug Eval} for other evaluation functions available | |
| 230 inside of Edebug. | |
| 231 | |
| 232 | |
| 233 @node Edebug Execution Modes | |
| 234 @subsection Edebug Execution Modes | |
| 235 | |
| 236 @cindex Edebug execution modes | |
| 237 Edebug supports several execution modes for running the program you are | |
| 238 debugging. We call these alternatives @dfn{Edebug execution modes}; do | |
| 239 not confuse them with major or minor modes. The current Edebug | |
| 240 execution mode determines how Edebug displays the progress of the | |
| 241 evaluation, whether it stops at each stop point, or continues to the | |
| 242 next breakpoint, for example. | |
| 243 | |
| 244 Normally, you specify the Edebug execution mode by typing a command | |
| 245 to continue the program in a certain mode. Here is a table of these | |
| 246 commands. All except for @kbd{S} resume execution of the program, at | |
| 247 least for a certain distance. | |
| 248 | |
| 249 @table @kbd | |
| 250 @item S | |
| 251 Stop: don't execute any more of the program for now, just wait for more | |
| 252 Edebug commands (@code{edebug-stop}). | |
| 253 | |
| 254 @item @key{SPC} | |
| 255 Step: stop at the next stop point encountered (@code{edebug-step-mode}). | |
| 256 | |
| 257 @item n | |
| 258 Next: stop at the next stop point encountered after an expression | |
| 259 (@code{edebug-next-mode}). Also see @code{edebug-forward-sexp} in | |
| 260 @ref{Edebug Misc}. | |
| 261 | |
| 262 @item t | |
| 263 Trace: pause one second at each Edebug stop point (@code{edebug-trace-mode}). | |
| 264 | |
| 265 @item T | |
| 266 Rapid trace: update at each stop point, but don't actually | |
| 267 pause (@code{edebug-Trace-fast-mode}). | |
| 268 | |
| 269 @item g | |
| 270 Go: run until the next breakpoint (@code{edebug-go-mode}). @xref{Breakpoints}. | |
| 271 | |
| 272 @item c | |
| 273 Continue: pause for one second at each breakpoint, but don't stop | |
| 274 (@code{edebug-continue-mode}). | |
| 275 | |
| 276 @item C | |
| 277 Rapid continue: update at each breakpoint, but don't actually pause | |
| 278 (@code{edebug-Continue-fast-mode}). | |
| 279 | |
| 280 @item G | |
| 281 Go non-stop: ignore breakpoints (@code{edebug-Go-nonstop-mode}). You | |
| 282 can still stop the program by hitting any key. | |
| 283 @end table | |
| 284 | |
| 285 In general, the execution modes earlier in the above list run the | |
| 286 program more slowly or stop sooner. | |
| 287 | |
| 288 When you enter a new Edebug level, the initial execution mode comes from | |
| 289 the value of the variable @code{edebug-initial-mode}. By default, this | |
| 290 specifies @code{step} mode. Note that you may reenter the same Edebug | |
| 444 | 291 level several times if, for example, an instrumented function is called |
| 428 | 292 several times from one command. |
| 293 | |
| 294 While executing or tracing, you can interrupt the execution by typing | |
| 295 any Edebug command. Edebug stops the program at the next stop point and | |
| 296 then executes the command that you typed. For example, typing @kbd{t} | |
| 297 during execution switches to trace mode at the next stop point. You can | |
| 298 use @kbd{S} to stop execution without doing anything else. | |
| 299 | |
| 300 If your function happens to read input, a character you hit intending to | |
| 301 interrupt execution may be read by the function instead. You can avoid | |
| 302 such unintended results by paying attention to when your program wants | |
| 303 input. | |
| 304 | |
| 305 @cindex keyboard macros (Edebug) | |
| 306 Keyboard macros containing Edebug commands do not work; when you exit | |
| 307 from Edebug, to resume the program, whether you are defining or | |
| 308 executing a keyboard macro is forgotten. Also, defining or executing a | |
| 309 keyboard macro outside of Edebug does not affect the command loop inside | |
| 310 Edebug. This is usually an advantage. But see | |
| 311 @code{edebug-continue-kbd-macro}. | |
| 312 | |
| 313 | |
| 314 @node Jumping | |
| 315 @subsection Jumping | |
| 316 | |
| 317 Commands described here let you jump to a specified location. | |
| 318 All, except @kbd{i}, use temporary breakpoints to establish the stop | |
| 319 point and then switch to @code{go} mode. Any other breakpoint reached | |
| 320 before the intended stop point will also stop execution. See | |
| 321 @ref{Breakpoints} for the details on breakpoints. | |
| 322 | |
| 323 @table @kbd | |
| 324 @item f | |
| 325 Run the program forward over one expression | |
| 326 (@code{edebug-forward-sexp}). More precisely, set a temporary | |
| 327 breakpoint at the position that @kbd{C-M-f} would reach, then execute in | |
| 328 @code{go} mode so that the program will stop at breakpoints. | |
| 329 | |
| 330 With a prefix argument @var{n}, the temporary breakpoint is placed | |
| 331 @var{n} sexps beyond point. If the containing list ends before @var{n} | |
| 332 more elements, then the place to stop is after the containing | |
| 333 expression. | |
| 334 | |
| 335 Be careful that the position @kbd{C-M-f} finds is a place that the | |
| 336 program will really get to; this may not be true in a | |
| 337 @code{cond}, for example. | |
| 338 | |
| 339 This command does @code{forward-sexp} starting at point rather than the | |
| 340 stop point. If you want to execute one expression from the current stop | |
| 341 point, type @kbd{w} first, to move point there. | |
| 342 | |
| 343 @item o | |
| 344 Continue ``out of'' an expression (@code{edebug-step-out}). It places a | |
| 444 | 345 temporary breakpoint at the end of the sexp containing point. |
| 428 | 346 |
| 347 If the containing sexp is a function definition itself, it continues | |
| 348 until just before the last sexp in the definition. If that is where you | |
| 349 are now, it returns from the function and then stops. In other words, | |
| 350 this command does not exit the currently executing function unless you | |
| 351 are positioned after the last sexp. | |
| 352 | |
| 353 @item I | |
| 354 Step into the function or macro after point after first ensuring that it | |
| 355 is instrumented. It does this by calling @code{edebug-on-entry} and | |
| 356 then switching to @code{go} mode. | |
| 357 | |
| 358 Although the automatic instrumentation is convenient, it is not | |
| 359 later automatically uninstrumented. | |
| 360 | |
| 361 @item h | |
| 362 Proceed to the stop point near where point is using a temporary | |
| 363 breakpoint (@code{edebug-goto-here}). | |
| 364 | |
| 365 @end table | |
| 366 | |
| 367 All the commands in this section may fail to work as expected in case | |
| 368 of nonlocal exit, because a nonlocal exit can bypass the temporary | |
| 369 breakpoint where you expected the program to stop. | |
| 370 | |
| 371 @node Edebug Misc | |
| 372 @subsection Miscellaneous | |
| 373 | |
| 374 Some miscellaneous commands are described here. | |
| 375 | |
| 376 @table @kbd | |
| 377 @item ? | |
| 378 Display the help message for Edebug (@code{edebug-help}). | |
| 379 | |
| 380 @item C-] | |
| 381 Abort one level back to the previous command level | |
| 382 (@code{abort-recursive-edit}). | |
| 383 | |
| 384 @item q | |
| 385 Return to the top level editor command loop (@code{top-level}). This | |
| 386 exits all recursive editing levels, including all levels of Edebug | |
| 387 activity. However, instrumented code protected with | |
| 388 @code{unwind-protect} or @code{condition-case} forms may resume | |
| 389 debugging. | |
| 390 | |
| 391 @item Q | |
| 392 Like @kbd{q} but don't stop even for protected code | |
| 393 (@code{top-level-nonstop}). | |
| 394 | |
| 395 @item r | |
| 396 Redisplay the most recently known expression result in the echo area | |
| 397 (@code{edebug-previous-result}). | |
| 398 | |
| 399 @item d | |
| 400 Display a backtrace, excluding Edebug's own functions for clarity | |
| 401 (@code{edebug-backtrace}). | |
| 402 | |
| 403 You cannot use debugger commands in the backtrace buffer in Edebug as | |
| 404 you would in the standard debugger. | |
| 405 | |
| 406 The backtrace buffer is killed automatically when you continue | |
| 407 execution. | |
| 408 @end table | |
| 409 | |
| 410 From the Edebug recursive edit, you may invoke commands that activate | |
| 411 Edebug again recursively. Any time Edebug is active, you can quit to | |
| 412 the top level with @kbd{q} or abort one recursive edit level with | |
| 444 | 413 @kbd{C-]}. You can display a backtrace of all the |
| 428 | 414 pending evaluations with @kbd{d}. |
| 415 | |
| 416 | |
| 417 @node Breakpoints | |
| 418 @subsection Breakpoints | |
| 419 | |
| 420 @cindex breakpoints | |
| 421 There are three more ways to stop execution once it has started: | |
| 422 breakpoints, the global break condition, and embedded breakpoints. | |
| 423 | |
| 424 While using Edebug, you can specify @dfn{breakpoints} in the program you | |
| 425 are testing: points where execution should stop. You can set a | |
| 426 breakpoint at any stop point, as defined in @ref{Using Edebug}. For | |
| 427 setting and unsetting breakpoints, the stop point that is affected is | |
| 428 the first one at or after point in the source code buffer. Here are the | |
| 429 Edebug commands for breakpoints: | |
| 430 | |
| 431 @table @kbd | |
| 432 @item b | |
| 433 Set a breakpoint at the stop point at or after point | |
| 434 (@code{edebug-set-breakpoint}). If you use a prefix argument, the | |
| 435 breakpoint is temporary (it turns off the first time it stops the | |
| 436 program). | |
| 437 | |
| 438 @item u | |
| 439 Unset the breakpoint (if any) at the stop point at or after the current | |
| 440 point (@code{edebug-unset-breakpoint}). | |
| 441 | |
| 442 @item x @var{condition} @key{RET} | |
| 443 Set a conditional breakpoint which stops the program only if | |
| 444 @var{condition} evaluates to a non-@code{nil} value | |
| 445 (@code{edebug-set-conditional-breakpoint}). If you use a prefix | |
| 446 argument, the breakpoint is temporary (it turns off the first time it | |
| 447 stops the program). | |
| 448 | |
| 449 @item B | |
| 450 Move point to the next breakpoint in the definition | |
| 451 (@code{edebug-next-breakpoint}). | |
| 452 @end table | |
| 453 | |
| 454 While in Edebug, you can set a breakpoint with @kbd{b} and unset one | |
| 455 with @kbd{u}. First you must move point to a position at or before the | |
| 456 desired Edebug stop point, then hit the key to change the breakpoint. | |
| 457 Unsetting a breakpoint that has not been set does nothing. | |
| 458 | |
| 459 Reevaluating or reinstrumenting a definition clears all its breakpoints. | |
| 460 | |
| 461 A @dfn{conditional breakpoint} tests a condition each time the program | |
| 462 gets there. To set a conditional breakpoint, use @kbd{x}, and specify | |
| 463 the condition expression in the minibuffer. Setting a conditional | |
| 464 breakpoint at a stop point that already has a conditional breakpoint | |
| 465 puts the current condition expression in the minibuffer so you can edit | |
| 466 it. | |
| 467 | |
| 468 You can make both conditional and unconditional breakpoints | |
| 469 @dfn{temporary} by using a prefix arg to the command to set the | |
| 470 breakpoint. After breaking at a temporary breakpoint, it is | |
| 471 automatically cleared. | |
| 472 | |
| 473 Edebug always stops or pauses at a breakpoint except when the Edebug | |
| 474 mode is @code{Go-nonstop}. In that mode, it ignores breakpoints entirely. | |
| 475 | |
| 476 To find out where your breakpoints are, use @kbd{B}, which | |
| 477 moves point to the next breakpoint in the definition following point, or | |
| 478 to the first breakpoint if there are no following breakpoints. This | |
| 479 command does not continue execution---it just moves point in the buffer. | |
| 480 | |
| 481 @menu | |
| 444 | 482 * Global Break Condition:: Breaking on an event. |
| 428 | 483 * Embedded Breakpoints:: Embedding breakpoints in code. |
| 484 @end menu | |
| 485 | |
| 486 | |
| 487 @node Global Break Condition | |
| 488 @subsubsection Global Break Condition | |
| 489 | |
| 490 @cindex stopping on events | |
| 491 @cindex global break condition | |
| 492 In contrast to breaking when execution reaches specified locations, | |
| 493 you can also cause a break when a certain event occurs. The @dfn{global | |
| 494 break condition} is a condition that is repeatedly evaluated at every | |
| 495 stop point. If it evaluates to a non-@code{nil} value, then execution | |
| 496 is stopped or paused depending on the execution mode, just like a | |
| 497 breakpoint. Any errors that might occur as a result of evaluating the | |
| 444 | 498 condition are ignored, as if the result were @code{nil}. |
| 428 | 499 |
| 500 @findex edebug-set-global-break-condition | |
| 501 @vindex edebug-global-break-condition | |
| 502 You can set or edit the condition expression, stored in | |
| 503 @code{edebug-global-break-condition}, using @kbd{X} | |
| 504 (@code{edebug-set-global-break-condition}). | |
| 505 | |
| 506 Using the global break condition is perhaps the fastest way | |
| 507 to find where in your code some event occurs, but since it is rather | |
| 508 expensive you should reset the condition to @code{nil} when not in use. | |
| 509 | |
| 510 | |
| 511 @node Embedded Breakpoints | |
| 512 @subsubsection Embedded Breakpoints | |
| 513 | |
| 514 @findex edebug | |
| 515 @cindex embedded breakpoints | |
| 516 Since all breakpoints in a definition are cleared each time you | |
| 517 reinstrument it, you might rather create an @dfn{embedded breakpoint} | |
| 518 which is simply a call to the function @code{edebug}. You can, of | |
| 519 course, make such a call conditional. For example, in the @code{fac} | |
| 520 function, insert the first line as shown below to stop when the argument | |
| 521 reaches zero: | |
| 522 | |
| 523 @example | |
| 524 (defun fac (n) | |
| 525 (if (= n 0) (edebug)) | |
| 526 (if (< 0 n) | |
| 527 (* n (fac (1- n))) | |
| 528 1)) | |
| 529 @end example | |
| 530 | |
| 531 When the @code{fac} definition is instrumented and the function is | |
| 532 called, Edebug will stop before the call to @code{edebug}. Depending on | |
| 533 the execution mode, Edebug will stop or pause. | |
| 534 | |
| 535 However, if no instrumented code is being executed, calling | |
| 536 @code{edebug} will instead invoke @code{debug}. Calling @code{debug} | |
| 537 will always invoke the standard backtrace debugger. | |
| 538 | |
| 539 | |
| 540 @node Trapping Errors | |
| 541 @subsection Trapping Errors | |
| 542 | |
| 543 @vindex edebug-on-error | |
| 544 @vindex edebug-on-quit | |
| 545 An error may be signaled by subroutines or XEmacs Lisp code. If a signal | |
| 546 is not handled by a @code{condition-case}, this indicates an | |
| 547 unrecognized situation has occurred. If Edebug is not active when an | |
| 548 unhandled error is signaled, @code{debug} is run normally (if | |
| 549 @code{debug-on-error} is non-@code{nil}). But while Edebug is active, | |
| 550 @code{debug-on-error} and @code{debug-on-quit} are bound to | |
| 551 @code{edebug-on-error} and @code{edebug-on-quit}, which are both | |
| 552 @code{t} by default. Actually, if @code{debug-on-error} already has | |
| 553 a non-@code{nil} value, that value is still used. | |
| 554 | |
| 555 It is best to change the values of @code{edebug-on-error} or | |
| 556 @code{edebug-on-quit} when Edebug is not active since their values won't | |
| 557 be used until the next time Edebug is invoked at a deeper command level. | |
| 558 If you only change @code{debug-on-error} or @code{debug-on-quit} while | |
| 559 Edebug is active, these changes will be forgotten when Edebug becomes | |
| 560 inactive. Furthermore, during Edebug's recursive edit, these variables | |
| 561 are bound to the values they had outside of Edebug. | |
| 562 | |
| 563 Edebug shows you the last stop point that it knew about before the | |
| 564 error was signaled. This may be the location of a call to a function | |
| 565 which was not instrumented, within which the error actually occurred. | |
| 566 For an unbound variable error, the last known stop point might be quite | |
| 567 distant from the offending variable. If the cause of the error is not | |
| 568 obvious at first, note that you can also get a full backtrace inside of | |
| 569 Edebug (see @ref{Edebug Misc}). | |
| 570 | |
| 571 Edebug can also trap signals even if they are handled. If | |
| 572 @code{debug-on-error} is a list of signal names, Edebug will stop when | |
| 573 any of these errors are signaled. Edebug shows you the last known stop | |
| 574 point just as for unhandled errors. After you continue execution, the | |
| 575 error is signaled again (but without being caught by Edebug). Edebug | |
| 576 can only trap errors that are handled if they are signaled in Lisp code | |
| 577 (not subroutines) since it does so by temporarily replacing the | |
| 578 @code{signal} function. | |
| 579 | |
| 580 | |
| 581 @node Edebug Views | |
| 582 @subsection Edebug Views | |
| 583 | |
| 584 The following Edebug commands let you view aspects of the buffer and | |
| 585 window status that obtained before entry to Edebug. | |
| 586 | |
| 587 @table @kbd | |
| 588 @item v | |
| 589 View the outside window configuration (@code{edebug-view-outside}). | |
| 590 | |
| 591 @item p | |
| 592 Temporarily display the outside current buffer with point at its outside | |
| 593 position (@code{edebug-bounce-point}). If prefix arg is supplied, sit for | |
| 594 that many seconds instead. | |
| 595 | |
| 596 @item w | |
| 597 Move point back to the current stop point (@code{edebug-where}) in the | |
| 598 source code buffer. Also, if you use this command in another window | |
| 599 displaying the same buffer, this window will be used instead to | |
| 600 display the buffer in the future. | |
| 601 | |
| 602 @item W | |
| 603 Toggle the @code{edebug-save-windows} variable which indicates whether | |
| 604 the outside window configuration is saved and restored | |
| 605 (@code{edebug-toggle-save-windows}). Also, each time it is toggled on, | |
| 606 make the outside window configuration the same as the current window | |
| 607 configuration. | |
| 608 | |
| 609 With a prefix argument, @code{edebug-toggle-save-windows} only toggles | |
| 610 saving and restoring of the selected window. To specify a window that | |
| 611 is not displaying the source code buffer, you must use @kbd{C-xXW} from | |
| 612 the global keymap. | |
| 613 | |
| 614 | |
| 615 @end table | |
| 616 | |
| 617 You can view the outside window configuration with @kbd{v} or just | |
| 618 bounce to the current point in the current buffer with @kbd{p}, even if | |
| 619 it is not normally displayed. After moving point, you may wish to pop | |
| 620 back to the stop point with @kbd{w} from a source code buffer. | |
| 621 | |
| 622 By using @kbd{W} twice, Edebug again saves and restores the | |
| 623 outside window configuration, but to the current configuration. This is | |
| 624 a convenient way to, for example, add another buffer to be displayed | |
| 625 whenever Edebug is active. However, the automatic redisplay of | |
| 626 @samp{*edebug*} and @samp{*edebug-trace*} may conflict with the buffers | |
| 627 you wish to see unless you have enough windows open. | |
| 628 | |
| 629 | |
| 630 @node Edebug Eval | |
| 631 @subsection Evaluation | |
| 632 | |
| 633 While within Edebug, you can evaluate expressions ``as if'' Edebug were | |
| 634 not running. Edebug tries to be invisible to the expression's | |
| 635 evaluation and printing. Evaluation of expressions that cause side | |
| 636 effects will work as expected except for things that Edebug explicitly | |
| 637 saves and restores. See @ref{The Outside Context} for details on this | |
| 638 process. Also see @ref{Reading in Edebug} and @ref{Printing in Edebug} | |
| 639 for topics related to evaluation. | |
| 640 | |
| 641 @table @kbd | |
| 642 @item e @var{exp} @key{RET} | |
| 643 Evaluate expression @var{exp} in the context outside of Edebug | |
| 644 (@code{edebug-eval-expression}). In other words, Edebug tries to avoid | |
| 645 altering the effect of @var{exp}. | |
| 646 | |
| 647 @item M-@key{ESC} @var{exp} @key{RET} | |
| 648 Evaluate expression @var{exp} in the context of Edebug itself. | |
| 649 | |
| 650 @item C-x C-e | |
| 651 Evaluate the expression before point, in the context outside of Edebug | |
| 652 (@code{edebug-eval-last-sexp}). | |
| 653 @end table | |
| 654 | |
| 655 @cindex lexical binding (Edebug) | |
| 656 Edebug supports evaluation of expressions containing references to | |
| 657 lexically bound symbols created by the following constructs in | |
| 658 @file{cl.el} (version 2.03 or later): @code{lexical-let}, | |
| 659 @code{macrolet}, and @code{symbol-macrolet}. | |
| 660 | |
| 661 | |
| 662 @node Eval List | |
| 663 @subsection Evaluation List Buffer | |
| 664 | |
| 665 You can use the @dfn{evaluation list buffer}, called @samp{*edebug*}, to | |
| 666 evaluate expressions interactively. You can also set up the | |
| 667 @dfn{evaluation list} of expressions to be evaluated automatically each | |
| 668 time Edebug updates the display. | |
| 669 | |
| 670 @table @kbd | |
| 671 @item E | |
| 672 Switch to the evaluation list buffer @samp{*edebug*} | |
| 673 (@code{edebug-visit-eval-list}). | |
| 674 @end table | |
| 675 | |
| 676 In the @samp{*edebug*} buffer you can use the commands of Lisp | |
| 677 Interaction as well as these special commands: | |
| 678 | |
| 679 @table @kbd | |
| 680 @item LFD | |
| 681 Evaluate the expression before point, in the outside context, and insert | |
| 682 the value in the buffer (@code{edebug-eval-print-last-sexp}). | |
| 683 | |
| 684 @item C-x C-e | |
| 685 Evaluate the expression before point, in the context outside of Edebug | |
| 686 (@code{edebug-eval-last-sexp}). | |
| 687 | |
| 688 @item C-c C-u | |
| 689 Build a new evaluation list from the first expression of each group, | |
| 690 reevaluate and redisplay (@code{edebug-update-eval-list}). Groups are | |
| 691 separated by comment lines. | |
| 692 | |
| 693 @item C-c C-d | |
| 694 Delete the evaluation list group that point is in | |
| 695 (@code{edebug-delete-eval-item}). | |
| 696 | |
| 697 @item C-c C-w | |
| 698 Switch back to the source code buffer at the current stop point | |
| 699 (@code{edebug-where}). | |
| 700 @end table | |
| 701 | |
| 702 You can evaluate expressions in the evaluation list window with | |
| 703 @kbd{LFD} or @kbd{C-x C-e}, just as you would in @samp{*scratch*}; | |
| 704 but they are evaluated in the context outside of Edebug. | |
| 705 | |
| 706 @cindex evaluation list (Edebug) | |
| 707 The expressions you enter interactively (and their results) are lost | |
| 708 when you continue execution unless you add them to the | |
| 709 evaluation list with @kbd{C-c C-u}. This command builds a new list from | |
| 710 the first expression of each @dfn{evaluation list group}. Groups are | |
| 711 separated by comment lines. Be careful not to add expressions that | |
| 712 execute instrumented code otherwise an infinite loop will result. | |
| 713 | |
| 714 When the evaluation list is redisplayed, each expression is displayed | |
| 715 followed by the result of evaluating it, and a comment line. If an | |
| 716 error occurs during an evaluation, the error message is displayed in a | |
| 717 string as if it were the result. Therefore expressions that, for | |
| 718 example, use variables not currently valid do not interrupt your | |
| 719 debugging. | |
| 720 | |
| 721 Here is an example of what the evaluation list window looks like after | |
| 722 several expressions have been added to it: | |
| 723 | |
| 724 @smallexample | |
| 725 (current-buffer) | |
| 726 #<buffer *scratch*> | |
| 727 ;--------------------------------------------------------------- | |
| 728 (selected-window) | |
| 729 #<window 16 on *scratch*> | |
| 730 ;--------------------------------------------------------------- | |
| 731 (point) | |
| 732 196 | |
| 733 ;--------------------------------------------------------------- | |
| 734 bad-var | |
| 735 "Symbol's value as variable is void: bad-var" | |
| 736 ;--------------------------------------------------------------- | |
| 737 (recursion-depth) | |
| 738 0 | |
| 739 ;--------------------------------------------------------------- | |
| 740 this-command | |
| 741 eval-last-sexp | |
| 742 ;--------------------------------------------------------------- | |
| 743 @end smallexample | |
| 744 | |
| 745 To delete a group, move point into it and type @kbd{C-c C-d}, or simply | |
| 746 delete the text for the group and update the evaluation list with | |
| 747 @kbd{C-c C-u}. When you add a new group, be sure it is separated from | |
| 748 its neighbors by a comment line. | |
| 749 | |
| 750 After selecting @samp{*edebug*}, you can return to the source code | |
| 751 buffer with @kbd{C-c C-w}. The @samp{*edebug*} buffer is killed when | |
| 752 you continue execution, and recreated next time it is needed. | |
| 753 | |
| 754 | |
| 755 @node Reading in Edebug | |
| 756 @subsection Reading in Edebug | |
| 757 | |
| 758 @cindex reading (Edebug) | |
| 759 To instrument a form, Edebug first reads the whole form. Edebug | |
| 760 replaces the standard Lisp Reader with its own reader that remembers the | |
| 761 positions of expressions. This reader is used by the Edebug | |
| 762 replacements for @code{eval-region}, @code{eval-defun}, | |
| 763 @code{eval-buffer}, and @code{eval-current-buffer}. | |
| 764 | |
| 765 @pindex cl-read | |
| 766 Another package, @file{cl-read.el}, replaces the standard reader with | |
| 767 one that understands Common Lisp reader macros. If you use that | |
| 768 package, Edebug will automatically load @file{edebug-cl-read.el} to | |
| 769 provide corresponding reader macros that remember positions of | |
| 770 expressions. If you define new reader macros, you will have to define | |
| 771 similar reader macros for Edebug. | |
| 772 | |
| 773 | |
| 774 @node Printing in Edebug | |
| 775 @subsection Printing in Edebug | |
| 776 | |
| 777 @cindex printing (Edebug) | |
| 778 @cindex printing circular structures | |
| 779 @pindex cust-print | |
| 780 If the result of an expression in your program contains a circular | |
| 781 reference, you may get an error when Edebug attempts to print it. You | |
| 782 can set @code{print-length} to a non-zero value to limit the print | |
| 783 length of lists (the number of cdrs), and in Emacs 19, set | |
| 784 @code{print-level} to a non-zero value to limit the print depth of | |
| 785 lists. But you can print such circular structures and structures that | |
| 786 share elements more informatively by using the @file{cust-print} | |
| 787 package. | |
| 788 | |
| 789 To load @file{cust-print} and activate custom printing only for Edebug, | |
| 790 simply use the command @kbd{M-x edebug-install-custom-print}. To | |
| 791 restore the standard print functions, use @kbd{M-x | |
| 792 edebug-uninstall-custom-print}. You can also activate custom printing | |
| 793 for printing in any Lisp code; see the package for details. | |
| 794 | |
| 795 Here is an example of code that creates a circular structure: | |
| 796 | |
| 797 @example | |
| 798 (progn | |
| 799 (edebug-install-custom-print) | |
| 800 (setq a '(x y)) | |
| 801 (setcar a a)) | |
| 802 @end example | |
| 803 | |
| 804 Edebug will print the result of the @code{setcar} as @samp{Result: | |
| 805 #1=(#1# y)}. The @samp{#1=} notation names the structure that follows | |
| 806 it, and the @samp{#1#} notation references the previously named | |
| 807 structure. This notation is used for any shared elements of lists or | |
| 808 vectors. | |
| 809 | |
| 810 @vindex edebug-print-length | |
| 811 @vindex edebug-print-level | |
| 812 @vindex edebug-print-circle | |
| 813 @vindex print-readably | |
| 814 Independent of whether @file{cust-print} is active, while printing | |
| 815 results Edebug binds @code{print-length}, @code{print-level}, and | |
| 816 @code{print-circle} to @code{edebug-print-length} (@code{50}), | |
| 817 @code{edebug-print-level} (@code{50}), and @code{edebug-print-circle} | |
| 818 (@code{t}) respectively, if these values are non-@code{nil}. Also, | |
| 819 @code{print-readably} is bound to @code{nil} since some objects simply | |
| 820 cannot be printed readably. | |
| 821 | |
| 822 | |
| 823 @node Tracing | |
| 824 @subsection Tracing | |
| 825 | |
| 826 @cindex tracing | |
| 827 In addition to automatic stepping through source code, which is also | |
| 828 called @emph{tracing} (see @ref{Edebug Execution Modes}), Edebug can | |
| 829 produce a traditional trace listing of execution in a separate buffer, | |
| 830 @samp{*edebug-trace*}. | |
| 831 | |
| 832 @findex edebug-print-trace-before | |
| 833 @findex edebug-print-trace-after | |
| 444 | 834 If the variable @code{edebug-trace} is non-@code{nil}, each function entry and |
| 428 | 835 exit adds lines to the trace buffer. On function entry, Edebug prints |
| 836 @samp{::::@{} followed by the function name and argument values. On | |
| 837 function exit, Edebug prints @samp{::::@}} followed by the function name | |
| 838 and result of the function. The number of @samp{:}s is computed from | |
| 839 the recursion depth. The balanced braces in the trace buffer can be | |
| 840 used to find the matching beginning or end of function calls. These | |
| 841 displays may be customized by replacing the functions | |
| 842 @code{edebug-print-trace-before} and @code{edebug-print-trace-after}, | |
| 843 which take an arbitrary message string to print. | |
| 844 | |
| 845 @findex edebug-tracing | |
| 846 The macro @code{edebug-tracing} provides tracing similar to function | |
| 847 enter and exit tracing, but for arbitrary expressions. This macro | |
| 848 should be explicitly inserted by you around expressions you wish to | |
| 849 trace the execution of. The first argument is a message string | |
| 850 (evaluated), and the rest are expressions to evaluate. The result of | |
| 851 the last expression is returned. | |
| 852 | |
| 853 @findex edebug-trace | |
| 854 Finally, you can insert arbitrary strings into the trace buffer with | |
| 855 explicit calls to @code{edebug-trace}. The arguments of this function | |
| 856 are the same as for @code{message}, but a newline is always inserted | |
| 857 after each string printed in this way. | |
| 858 | |
| 859 @code{edebug-tracing} and @code{edebug-trace} insert lines in the trace | |
| 860 buffer even if Edebug is not active. Every time the trace buffer is | |
| 861 added to, the window is scrolled to show the last lines inserted. | |
| 862 (There may be some display problems if you use tracing along with the | |
| 863 evaluation list.) | |
| 864 | |
| 865 | |
| 866 @node Coverage Testing | |
| 867 @subsection Coverage Testing | |
| 868 | |
| 869 @cindex coverage testing | |
| 870 @cindex frequency counts | |
| 871 @cindex performance analysis | |
| 872 Edebug provides a rudimentary coverage tester and display of execution | |
| 873 frequency. Frequency counts are always accumulated, both before and | |
| 874 after evaluation of each instrumented expression, even if the execution | |
| 875 mode is @code{Go-nonstop}. Coverage testing is only done if the option | |
| 876 @code{edebug-test-coverage} is non-@code{nil} because this is relatively | |
| 877 expensive. Both data sets are displayed by @kbd{M-x | |
| 878 edebug-display-freq-count}. | |
| 879 | |
| 880 @deffn Command edebug-display-freq-count | |
| 881 Display the frequency count data for each line of the current | |
| 882 definition. The frequency counts are inserted as comment lines after | |
| 883 each line, and you can undo all insertions with one @code{undo} command. | |
| 884 The counts are inserted starting under the @kbd{(} before an expression | |
| 885 or the @kbd{)} after an expression, or on the last char of a symbol. | |
| 886 The counts are only displayed when they differ from previous counts on | |
| 887 the same line. | |
| 888 | |
| 889 If coverage is being tested, whenever all known results of an expression | |
| 890 are @code{eq}, the char @kbd{=} will be appended after the count | |
| 891 for that expression. Note that this is always the case for an | |
| 892 expression only evaluated once. | |
| 893 | |
| 894 To clear the frequency count and coverage data for a definition, | |
| 895 reinstrument it. | |
| 896 | |
| 897 @end deffn | |
| 898 | |
| 899 For example, after evaluating @code{(fac 5)} with an embedded | |
| 900 breakpoint, and setting @code{edebug-test-coverage} to @code{t}, when | |
| 901 the breakpoint is reached, the frequency data is looks like this: | |
| 902 | |
| 903 @example | |
| 904 (defun fac (n) | |
| 905 (if (= n 0) (edebug)) | |
| 444 | 906 ;#6 1 0 =5 |
| 428 | 907 (if (< 0 n) |
| 444 | 908 ;#5 = |
| 428 | 909 (* n (fac (1- n))) |
| 444 | 910 ;# 5 0 |
| 428 | 911 1)) |
| 444 | 912 ;# 0 |
| 428 | 913 @end example |
| 914 | |
| 915 The comment lines show that @code{fac} has been called 6 times. The | |
| 916 first @code{if} statement has returned 5 times with the same result each | |
| 917 time, and the same is true for the condition on the second @code{if}. | |
| 918 The recursive call of @code{fac} has not returned at all. | |
| 919 | |
| 920 | |
| 921 @node The Outside Context | |
| 922 @subsection The Outside Context | |
| 923 | |
| 924 Edebug tries to be transparent to the program you are debugging. In | |
| 925 addition, most evaluations you do within Edebug (see @ref{Edebug Eval}) | |
| 926 occur in the same outside context which is temporarily restored for the | |
| 927 evaluation. But Edebug is not completely successful and this section | |
| 928 explains precisely how it fails. Edebug operation unavoidably alters | |
| 929 some data in XEmacs, and this can interfere with debugging certain | |
| 930 programs. Also notice that Edebug's protection against change of | |
| 931 outside data means that any side effects @emph{intended} by the user in | |
| 932 the course of debugging will be defeated. | |
| 933 | |
| 934 @menu | |
| 935 * Checking Whether to Stop:: When Edebug decides what to do. | |
| 936 * Edebug Display Update:: When Edebug updates the display. | |
| 937 * Edebug Recursive Edit:: When Edebug stops execution. | |
| 938 @end menu | |
| 939 | |
| 940 | |
| 941 @node Checking Whether to Stop | |
| 942 @subsubsection Checking Whether to Stop | |
| 943 | |
| 944 Whenever Edebug is entered just to think about whether to take some | |
| 945 action, it needs to save and restore certain data. | |
| 946 | |
| 947 @itemize @bullet | |
| 444 | 948 @item |
| 428 | 949 @code{max-lisp-eval-depth} and @code{max-specpdl-size} are both |
| 950 incremented one time to reduce Edebug's impact on the stack. | |
| 951 You could, however, still run out of stack space when using Edebug. | |
| 952 | |
| 444 | 953 @item |
| 428 | 954 The state of keyboard macro execution is saved and restored. While |
| 955 Edebug is active, @code{executing-macro} is bound to | |
| 956 @code{edebug-continue-kbd-macro}. | |
| 957 | |
| 958 @end itemize | |
| 959 | |
| 960 | |
| 961 @node Edebug Display Update | |
| 962 @subsubsection Edebug Display Update | |
| 963 | |
| 964 When Edebug needs to display something (e.g., in trace mode), it saves | |
| 965 the current window configuration from ``outside'' Edebug. When you exit | |
| 966 Edebug (by continuing the program), it restores the previous window | |
| 967 configuration. | |
| 968 | |
| 969 XEmacs redisplays only when it pauses. Usually, when you continue | |
| 970 execution, the program comes back into Edebug at a breakpoint or after | |
| 971 stepping without pausing or reading input in between. In such cases, | |
| 972 XEmacs never gets a chance to redisplay the ``outside'' configuration. | |
| 973 What you see is the same window configuration as the last time Edebug | |
| 974 was active, with no interruption. | |
| 975 | |
| 976 Entry to Edebug for displaying something also saves and restores the | |
| 977 following data, but some of these are deliberately not restored if an | |
| 978 error or quit signal occurs. | |
| 979 | |
| 980 @itemize @bullet | |
| 444 | 981 @item |
| 428 | 982 @cindex current buffer point and mark (Edebug) |
| 983 Which buffer is current, and where point and mark are in the current | |
| 984 buffer are saved and restored. | |
| 985 | |
| 444 | 986 @item |
| 428 | 987 @cindex window configuration (Edebug) |
| 988 @findex save-excursion (Edebug) | |
| 989 @vindex edebug-save-windows | |
| 990 The Edebug Display Update, is saved and restored if | |
| 991 @code{edebug-save-windows} is non-@code{nil}. It is not restored on | |
| 992 error or quit, but the outside selected window @emph{is} reselected even | |
| 444 | 993 on error or quit in case a @code{save-excursion} is active. |
| 428 | 994 If the value of @code{edebug-save-windows} is a list, only the listed |
| 995 windows are saved and restored. | |
| 996 | |
| 997 The window start and horizontal scrolling of the source code buffer are | |
| 998 not restored, however, so that the display remains coherent. | |
| 999 | |
| 1000 @item | |
| 1001 @vindex edebug-save-displayed-buffer-points | |
| 1002 The value of point in each displayed buffer is saved and restored if | |
| 1003 @code{edebug-save-displayed-buffer-points} is non-@code{nil}. | |
| 1004 | |
| 1005 @item | |
| 1006 The variables @code{overlay-arrow-position} and | |
| 1007 @code{overlay-arrow-string} are saved and restored. So you can safely | |
| 1008 invoke Edebug from the recursive edit elsewhere in the same buffer. | |
| 1009 | |
| 444 | 1010 @item |
| 428 | 1011 @code{cursor-in-echo-area} is locally bound to @code{nil} so that |
| 1012 the cursor shows up in the window. | |
| 1013 | |
| 1014 @end itemize | |
| 1015 | |
| 1016 | |
| 1017 @node Edebug Recursive Edit | |
| 1018 @subsubsection Edebug Recursive Edit | |
| 1019 | |
| 1020 When Edebug is entered and actually reads commands from the user, it | |
| 1021 saves (and later restores) these additional data: | |
| 1022 | |
| 1023 @itemize @bullet | |
| 1024 @item | |
| 1025 The current match data, for whichever buffer was current. | |
| 1026 | |
| 1027 @item | |
| 1028 @code{last-command}, @code{this-command}, @code{last-command-char}, | |
| 1029 @code{last-input-char}, @code{last-input-event}, | |
| 1030 @code{last-command-event}, | |
| 1031 @code{last-event-frame}, @code{last-nonmenu-event}, and | |
| 1032 @code{track-mouse} . Commands used within Edebug do not affect these | |
| 1033 variables outside of Edebug. | |
| 1034 | |
| 1035 The key sequence returned by @code{this-command-keys} is changed by | |
| 1036 executing commands within Edebug and there is no way to reset | |
| 1037 the key sequence from Lisp. | |
| 1038 | |
| 1039 For Emacs 18, Edebug cannot save and restore the value of | |
| 1040 @code{unread-command-char}. Entering Edebug while this variable has | |
| 1041 a nontrivial value can interfere with execution of the program you are | |
| 1042 debugging. | |
| 1043 | |
| 1044 @item | |
| 1045 Complex commands executed while in Edebug are added to the variable | |
| 1046 @code{command-history}. In rare cases this can alter execution. | |
| 1047 | |
| 1048 @item | |
| 1049 Within Edebug, the recursion depth appears one deeper than the recursion | |
| 1050 depth outside Edebug. This is not true of the automatically updated | |
| 1051 evaluation list window. | |
| 1052 | |
| 1053 @item | |
| 1054 @code{standard-output} and @code{standard-input} are bound to @code{nil} | |
| 1055 by the @code{recursive-edit}, but Edebug temporarily restores them during | |
| 1056 evaluations. | |
| 1057 | |
| 444 | 1058 @item |
| 428 | 1059 The state of keyboard macro definition is saved and restored. While |
| 1060 Edebug is active, @code{defining-kbd-macro} is bound to | |
| 1061 @code{edebug-continue-kbd-macro}. | |
| 1062 | |
| 1063 @end itemize | |
| 1064 | |
| 1065 | |
| 1066 @node Instrumenting Macro Calls | |
| 1067 @subsection Instrumenting Macro Calls | |
| 1068 | |
| 1069 When Edebug instruments an expression that calls a Lisp macro, it needs | |
| 1070 additional advice to do the job properly. This is because there is no | |
| 1071 way to tell which subexpressions of the macro call may be evaluated. | |
| 1072 (Evaluation may occur explicitly in the macro body, or when the | |
| 1073 resulting expansion is evaluated, or any time later.) You must explain | |
| 1074 the format of macro call arguments by using @code{def-edebug-spec} to | |
| 1075 define an @dfn{Edebug specification} for each macro. | |
| 1076 | |
| 444 | 1077 @defmac def-edebug-spec macro specification |
| 428 | 1078 Specify which expressions of a call to macro @var{macro} are forms to be |
| 1079 evaluated. For simple macros, the @var{specification} often looks very | |
| 1080 similar to the formal argument list of the macro definition, but | |
| 1081 specifications are much more general than macro arguments. | |
| 1082 | |
| 1083 The @var{macro} argument may actually be any symbol, not just a macro | |
| 1084 name. | |
| 1085 | |
| 1086 Unless you are using Emacs 19 or XEmacs, this macro is only defined | |
| 1087 in Edebug, so you may want to use the following which is equivalent: | |
| 1088 @code{(put '@var{macro} 'edebug-form-spec '@var{specification})} | |
| 444 | 1089 @end defmac |
| 428 | 1090 |
| 1091 Here is a simple example that defines the specification for the | |
| 1092 @code{for} macro described in the XEmacs Lisp Reference Manual, followed | |
| 1093 by an alternative, equivalent specification. | |
| 1094 | |
| 1095 @example | |
| 1096 (def-edebug-spec for | |
| 1097 (symbolp "from" form "to" form "do" &rest form)) | |
| 1098 | |
| 1099 (def-edebug-spec for | |
| 1100 (symbolp ['from form] ['to form] ['do body])) | |
| 1101 @end example | |
| 1102 | |
| 1103 Here is a table of the possibilities for @var{specification} and how each | |
| 1104 directs processing of arguments. | |
| 1105 | |
| 1106 @table @bullet | |
| 1107 | |
| 1108 @item @code{t} | |
| 1109 All arguments are instrumented for evaluation. | |
| 1110 | |
| 1111 @item @code{0} | |
| 1112 None of the arguments is instrumented. | |
| 1113 | |
| 1114 @item a symbol | |
| 1115 The symbol must have an Edebug specification which is used instead. | |
| 1116 This indirection is repeated until another kind of specification is | |
| 1117 found. This allows you to inherit the specification for another macro. | |
| 1118 | |
| 1119 @item a list | |
| 1120 The elements of the list describe the types of the arguments of a | |
| 1121 calling form. The possible elements of a specification list are | |
| 1122 described in the following sections. | |
| 1123 @end table | |
| 1124 | |
| 1125 @menu | |
| 1126 * Specification List:: How to specify complex patterns of evaluation. | |
| 1127 * Backtracking:: What Edebug does when matching fails. | |
| 1128 * Debugging Backquote:: Debugging Backquote | |
| 1129 * Specification Examples:: To help understand specifications. | |
| 1130 @end menu | |
| 1131 | |
| 1132 | |
| 1133 @node Specification List | |
| 1134 @subsubsection Specification List | |
| 1135 | |
| 1136 @cindex Edebug specification list | |
| 1137 A @dfn{specification list} is required for an Edebug specification if | |
| 1138 some arguments of a macro call are evaluated while others are not. Some | |
| 1139 elements in a specification list match one or more arguments, but others | |
| 1140 modify the processing of all following elements. The latter, called | |
| 1141 @dfn{keyword specifications}, are symbols beginning with @samp{@code{&}} | |
| 1142 (e.g. @code{&optional}). | |
| 1143 | |
| 1144 A specification list may contain sublists which match arguments that are | |
| 1145 themselves lists, or it may contain vectors used for grouping. Sublists | |
| 1146 and groups thus subdivide the specification list into a hierarchy of | |
| 1147 levels. Keyword specifications only apply to the remainder of the | |
| 1148 sublist or group they are contained in and there is an implicit grouping | |
| 1149 around a keyword specification and all following elements in the | |
| 1150 sublist or group. | |
| 1151 | |
| 1152 If a specification list fails | |
| 1153 at some level, then backtracking may be invoked to find some alternative | |
| 1154 at a higher level, or if no alternatives remain, an error will be | |
| 1155 signaled. See @ref{Backtracking} for more details. | |
| 1156 | |
| 1157 Edebug specifications provide at least the power of regular expression | |
| 1158 matching. Some context-free constructs are also supported: the matching | |
| 1159 of sublists with balanced parentheses, recursive processing of forms, | |
| 1160 and recursion via indirect specifications. | |
| 1161 | |
| 1162 Each element of a specification list may be one of the following, with | |
| 1163 the corresponding type of argument: | |
| 1164 | |
| 1165 @table @code | |
| 1166 | |
| 1167 @item sexp | |
| 1168 A single unevaluated expression. | |
| 1169 | |
| 1170 @item form | |
| 1171 A single evaluated expression, which is instrumented. | |
| 1172 | |
| 1173 @item place | |
| 1174 @findex edebug-unwrap | |
| 1175 A place as in the Common Lisp @code{setf} place argument. It will be | |
| 1176 instrumented just like a form, but the macro is expected to strip the | |
| 1177 instrumentation. Two functions, @code{edebug-unwrap} and | |
| 1178 @code{edebug-unwrap*}, are provided to strip the instrumentation one | |
| 1179 level or recursively at all levels. | |
| 1180 | |
| 1181 @item body | |
| 1182 Short for @code{&rest form}. See @code{&rest} below. | |
| 1183 | |
| 1184 @item function-form | |
| 1185 A function form: either a quoted function symbol, a quoted lambda expression, | |
| 1186 or a form (that should evaluate to a function symbol or lambda | |
| 1187 expression). This is useful when function arguments might be quoted | |
| 1188 with @code{quote} rather than @code{function} since the body of a lambda | |
| 1189 expression will be instrumented either way. | |
| 1190 | |
| 1191 @item lambda-expr | |
| 1192 An unquoted anonymous lambda expression. | |
| 1193 | |
| 1194 @item &optional | |
| 1195 @cindex &optional (Edebug) | |
| 1196 All following elements in the specification list are optional; as soon | |
| 444 | 1197 as one does not match, Edebug stops matching at this level. |
| 428 | 1198 |
| 1199 To make just a few elements optional followed by non-optional elements, | |
| 1200 use @code{[&optional @var{specs}@dots{}]}. To specify that several | |
| 1201 elements should all succeed together, use @code{&optional | |
| 1202 [@var{specs}@dots{}]}. See the @code{defun} example below. | |
| 1203 | |
| 1204 @item &rest | |
| 1205 @cindex &rest (Edebug) | |
| 1206 All following elements in the specification list are repeated zero or | |
| 1207 more times. All the elements need not match in the last repetition, | |
| 1208 however. | |
| 1209 | |
| 1210 To repeat only a few elements, use @code{[&rest @var{specs}@dots{}]}. | |
| 1211 To specify all elements must match on every repetition, use @code{&rest | |
| 1212 [@var{specs}@dots{}]}. | |
| 1213 | |
| 1214 @item &or | |
| 1215 @cindex &or (Edebug) | |
| 1216 Each of the following elements in the specification list is an | |
| 1217 alternative, processed left to right until one matches. One of the | |
| 1218 alternatives must match otherwise the @code{&or} specification fails. | |
| 1219 | |
| 1220 Each list element following @code{&or} is a single alternative even if | |
| 1221 it is a keyword specification. (This breaks the implicit grouping rule.) | |
| 1222 To group two or more list elements as a single alternative, enclose them | |
| 1223 in @code{[@dots{}]}. | |
| 1224 | |
| 1225 @item ¬ | |
| 1226 @cindex ¬ (Edebug) | |
| 1227 Each of the following elements is matched as alternatives as if by using | |
| 1228 @code{&or}, but if any of them match, the specification fails. If none | |
| 1229 of them match, nothing is matched, but the @code{¬} specification | |
| 1230 succeeds. | |
| 1231 | |
| 444 | 1232 @item &define |
| 428 | 1233 @cindex &define (Edebug) |
| 1234 Indicates that the specification is for a defining form. The defining | |
| 1235 form itself is not instrumented (i.e. Edebug does not stop before and | |
| 1236 after the defining form), but forms inside it typically will be | |
| 1237 instrumented. The @code{&define} keyword should be the first element in | |
| 1238 a list specification. | |
| 1239 | |
| 1240 Additional specifications that may only appear after @code{&define} are | |
| 1241 described here. See the @code{defun} example below. | |
| 1242 | |
| 1243 @table @code | |
| 1244 | |
| 1245 @item name | |
| 444 | 1246 The argument, a symbol, is the name of the defining form. |
| 428 | 1247 But a defining form need not be named at all, in which |
| 1248 case a unique name will be created for it. | |
| 1249 | |
| 1250 The @code{name} specification may be used more than once in the | |
| 1251 specification and each subsequent use will append the corresponding | |
| 1252 symbol argument to the previous name with @samp{@code{@@}} between them. | |
| 1253 This is useful for generating unique but meaningful names for | |
| 1254 definitions such as @code{defadvice} and @code{defmethod}. | |
| 1255 | |
| 1256 @item :name | |
| 1257 The element following @code{:name} should be a symbol; it is used as an | |
| 1258 additional name component for the definition. This is useful to add a | |
| 1259 unique, static component to the name of the definition. It may be used | |
| 1260 more than once. No argument is matched. | |
| 1261 | |
| 1262 @item arg | |
| 1263 The argument, a symbol, is the name of an argument of the defining form. | |
| 1264 However, lambda list keywords (symbols starting with @samp{@code{&}}) | |
| 1265 are not allowed. See @code{lambda-list} and the example below. | |
| 1266 | |
| 1267 @item lambda-list | |
| 1268 @cindex lambda-list (Edebug) | |
| 1269 This matches the whole argument list of an XEmacs Lisp lambda | |
| 1270 expression, which is a list of symbols and the keywords | |
| 1271 @code{&optional} and @code{&rest} | |
| 1272 | |
| 1273 @item def-body | |
| 1274 The argument is the body of code in a definition. This is like | |
| 1275 @code{body}, described above, but a definition body must be instrumented | |
| 1276 with a different Edebug call that looks up information associated with | |
| 1277 the definition. Use @code{def-body} for the highest level list of forms | |
| 1278 within the definition. | |
| 1279 | |
| 1280 @item def-form | |
| 1281 The argument is a single, highest-level form in a definition. This is | |
| 1282 like @code{def-body}, except use this to match a single form rather than | |
| 1283 a list of forms. As a special case, @code{def-form} also means that | |
| 1284 tracing information is not output when the form is executed. See the | |
| 1285 @code{interactive} example below. | |
| 1286 | |
| 1287 @end table | |
| 1288 | |
| 1289 @item nil | |
| 1290 This is successful when there are no more arguments to match at the | |
| 1291 current argument list level; otherwise it fails. See sublist | |
| 1292 specifications and the backquote example below. | |
| 1293 | |
| 1294 @item gate | |
| 1295 @cindex preventing backtracking | |
| 1296 No argument is matched but backtracking through the gate is disabled | |
| 1297 while matching the remainder of the specifications at this level. This | |
| 1298 is primarily used to generate more specific syntax error messages. See | |
| 1299 @ref{Backtracking} for more details. Also see the @code{let} example | |
| 1300 below. | |
| 1301 | |
| 1302 @item @var{other-symbol} | |
| 1303 @cindex indirect specifications | |
| 1304 Any other symbol in a specification list may be a predicate or an | |
| 1305 indirect specification. | |
| 1306 | |
| 1307 If the symbol has an Edebug specification, this @dfn{indirect | |
| 1308 specification} should be either a list specification that is used in | |
| 1309 place of the symbol, or a function that is called to process the | |
| 1310 arguments. The specification may be defined with @code{def-edebug-spec} | |
| 1311 just as for macros. See the @code{defun} example below. | |
| 1312 | |
| 1313 Otherwise, the symbol should be a predicate. The predicate is called | |
| 1314 with the argument and the specification fails if the predicate fails. | |
| 1315 The argument is not instrumented. | |
| 1316 | |
| 1317 @findex keywordp | |
| 1318 @findex lambda-list-keywordp | |
| 1319 Predicates that may be used include: @code{symbolp}, @code{integerp}, | |
| 1320 @code{stringp}, @code{vectorp}, @code{atom} (which matches a number, | |
| 1321 string, symbol, or vector), @code{keywordp}, and | |
| 1322 @code{lambda-list-keywordp}. The last two, defined in @file{edebug.el}, | |
| 1323 test whether the argument is a symbol starting with @samp{@code{:}} and | |
| 1324 @samp{@code{&}} respectively. | |
| 1325 | |
| 1326 @item [@var{elements}@dots{}] | |
| 1327 @cindex [@dots{}] (Edebug) | |
| 1328 Rather than matching a vector argument, a vector treats | |
| 1329 the @var{elements} as a single @dfn{group specification}. | |
| 1330 | |
| 1331 @item "@var{string}" | |
| 1332 The argument should be a symbol named @var{string}. This specification | |
| 1333 is equivalent to the quoted symbol, @code{'@var{symbol}}, where the name | |
| 1334 of @var{symbol} is the @var{string}, but the string form is preferred. | |
| 1335 | |
| 1336 @item '@var{symbol} @r{or} (quote @var{symbol}) | |
| 1337 The argument should be the symbol @var{symbol}. But use a string | |
| 1338 specification instead. | |
| 1339 | |
| 1340 @item (vector @var{elements}@dots{}) | |
| 1341 The argument should be a vector whose elements must match the | |
| 1342 @var{elements} in the specification. See the backquote example below. | |
| 1343 | |
| 1344 @item (@var{elements}@dots{}) | |
| 1345 Any other list is a @dfn{sublist specification} and the argument must be | |
| 1346 a list whose elements match the specification @var{elements}. | |
| 1347 | |
| 1348 @cindex dotted lists (Edebug) | |
| 1349 A sublist specification may be a dotted list and the corresponding list | |
| 1350 argument may then be a dotted list. Alternatively, the last cdr of a | |
| 1351 dotted list specification may be another sublist specification (via a | |
| 1352 grouping or an indirect specification, e.g. @code{(spec . [(more | |
| 1353 specs@dots{})])}) whose elements match the non-dotted list arguments. | |
| 1354 This is useful in recursive specifications such as in the backquote | |
| 1355 example below. Also see the description of a @code{nil} specification | |
| 1356 above for terminating such recursion. | |
| 1357 | |
| 1358 Note that a sublist specification of the form @code{(specs . nil)} | |
| 1359 means the same as @code{(specs)}, and @code{(specs . | |
| 1360 (sublist-elements@dots{}))} means the same as @code{(specs | |
| 1361 sublist-elements@dots{})}. | |
| 1362 | |
| 1363 @end table | |
| 1364 | |
| 1365 @c Need to document extensions with &symbol and :symbol | |
| 1366 | |
| 1367 @node Backtracking | |
| 1368 @subsubsection Backtracking | |
| 1369 | |
| 1370 @cindex backtracking | |
| 1371 @cindex syntax error (Edebug) | |
| 1372 If a specification fails to match at some point, this does not | |
| 1373 necessarily mean a syntax error will be signaled; instead, | |
| 1374 @dfn{backtracking} will take place until all alternatives have been | |
| 1375 exhausted. Eventually every element of the argument list must be | |
| 1376 matched by some element in the specification, and every required element | |
| 1377 in the specification must match some argument. | |
| 1378 | |
| 1379 Backtracking is disabled for the remainder of a sublist or group when | |
| 1380 certain conditions occur, described below. Backtracking is reenabled | |
| 1381 when a new alternative is established by @code{&optional}, @code{&rest}, | |
| 1382 or @code{&or}. It is also reenabled initially when processing a | |
| 1383 sublist or group specification or an indirect specification. | |
| 1384 | |
| 1385 You might want to disable backtracking to commit to some alternative so | |
| 1386 that Edebug can provide a more specific syntax error message. Normally, | |
| 1387 if no alternative matches, Edebug reports that none matched, but if one | |
| 1388 alternative is committed to, Edebug can report how it failed to match. | |
| 1389 | |
| 1390 First, backtracking is disabled while matching any of the form | |
| 1391 specifications (i.e. @code{form}, @code{body}, @code{def-form}, and | |
| 1392 @code{def-body}). These specifications will match any form so any error | |
| 1393 must be in the form itself rather than at a higher level. | |
| 1394 | |
| 1395 Second, backtracking is disabled after successfully matching a quoted | |
| 1396 symbol or string specification, since this usually indicates a | |
| 1397 recognized construct. If you have a set of alternative constructs that | |
| 1398 all begin with the same symbol, you can usually work around this | |
| 1399 constraint by factoring the symbol out of the alternatives, e.g., | |
| 1400 @code{["foo" &or [first case] [second case] ...]}. | |
| 1401 | |
| 1402 Third, backtracking may be explicitly disabled by using the | |
| 1403 @code{gate} specification. This is useful when you know that | |
| 1404 no higher alternatives may apply. | |
| 1405 | |
| 1406 | |
| 1407 @node Debugging Backquote | |
| 1408 @subsubsection Debugging Backquote | |
| 1409 | |
| 1410 @findex ` (Edebug) | |
| 1411 @cindex backquote (Edebug) | |
| 1412 Backquote (@kbd{`}) is a macro that results in an expression that may or | |
| 1413 may not be evaluated. It is often used to simplify the definition of a | |
| 1414 macro to return an expression that is evaluated, but Edebug does not know | |
| 1415 when this is the case. However, the forms inside unquotes (@code{,} and | |
| 1416 @code{,@@}) are evaluated and Edebug instruments them. | |
| 1417 | |
| 1418 Nested backquotes are supported by Edebug, but there is a limit on the | |
| 1419 support of quotes inside of backquotes. Quoted forms (with @code{'}) | |
| 1420 are not normally evaluated, but if the quoted form appears immediately | |
| 1421 within @code{,} and @code{,@@} forms, Edebug treats this as a backquoted | |
| 1422 form at the next higher level (even if there is not a next higher level | |
| 1423 - this is difficult to fix). | |
| 1424 | |
| 1425 @findex edebug-` | |
| 1426 If the backquoted forms happen to be code intended to be evaluated, you | |
| 1427 can have Edebug instrument them by using @code{edebug-`} instead of the | |
| 1428 regular @code{`}. Unquoted forms can always appear inside | |
| 1429 @code{edebug-`} anywhere a form is normally allowed. But @code{(, | |
| 1430 @var{form})} may be used in two other places specially recognized by | |
| 1431 Edebug: wherever a predicate specification would match, and at the head | |
| 1432 of a list form in place of a function name or lambda expression. The | |
| 1433 @var{form} inside a spliced unquote, @code{(,@@ @var{form})}, will be | |
| 1434 wrapped, but the unquote form itself will not be wrapped since this | |
| 1435 would interfere with the splicing. | |
| 1436 | |
| 1437 There is one other complication with using @code{edebug-`}. If the | |
| 1438 @code{edebug-`} call is in a macro and the macro may be called from code | |
| 1439 that is also instrumented, and if unquoted forms contain any macro | |
| 1440 arguments bound to instrumented forms, then you should modify the | |
| 1441 specification for the macro as follows: the specifications for those | |
| 1442 arguments must use @code{def-form} instead of @code{form}. (This is to | |
| 1443 reestablish the Edebugging context for those external forms.) | |
| 1444 | |
| 444 | 1445 For example, the @code{for} macro |
| 428 | 1446 @c (@pxref{Problems with Macros}) @c in XEmacs Lisp Reference Manual |
| 1447 (@pxref{Problems with Macros,,,, XEmacs Lisp Reference Manual}) @c Edebug Doc | |
| 1448 is shown here but with @code{edebug-`} | |
| 1449 substituted for regular @code{`}. | |
| 1450 | |
| 1451 @example | |
| 1452 (defmacro inc (var) | |
| 1453 (list 'setq var (list '1+ var))) | |
| 1454 | |
| 1455 (defmacro for (var from init to final do &rest body) | |
| 1456 (let ((tempvar (make-symbol "max"))) | |
| 1457 (edebug-` (let (((, var) (, init)) | |
| 1458 ((, tempvar) (, final))) | |
| 1459 (while (<= (, var) (, tempvar)) | |
| 1460 (,@ body) | |
| 1461 (inc (, var))))))) | |
| 1462 @end example | |
| 1463 | |
| 1464 Here is the corresponding modified Edebug specification and some code | |
| 1465 that calls the macro: | |
| 1466 | |
| 1467 @example | |
| 1468 (def-edebug-spec for | |
| 1469 (symbolp "from" def-form "to" def-form "do" &rest def-form)) | |
| 1470 | |
| 1471 (let ((n 5)) | |
| 1472 (for i from n to (* n (+ n 1)) do | |
| 1473 (message "%s" i))) | |
| 1474 @end example | |
| 1475 | |
| 1476 After instrumenting the @code{for} macro and the macro call, Edebug | |
| 1477 first steps to the beginning of the macro call, then into the macro | |
| 1478 body, then through each of the unquoted expressions in the backquote | |
| 1479 showing the expressions that will be embedded in the backquote form. | |
| 1480 Then when the macro expansion is evaluated, Edebug will step through the | |
| 1481 @code{let} form and each time it gets to an unquoted form, it will jump | |
| 1482 back to an argument of the macro call to step through that expression. | |
| 1483 Finally stepping will continue after the macro call. Even more | |
| 1484 convoluted execution paths may result when using anonymous functions. | |
| 1485 | |
| 1486 @vindex edebug-unwrap-results | |
| 1487 When the result of an expression is an instrumented expression, it is | |
| 1488 difficult to see the expression inside the instrumentation. So | |
| 1489 you may want to set the option @code{edebug-unwrap-results} to a | |
| 1490 non-@code{nil} value while debugging such expressions, but it would slow | |
| 1491 Edebug down to always do this. | |
| 1492 | |
| 1493 | |
| 1494 @node Specification Examples | |
| 1495 @subsubsection Specification Examples | |
| 1496 | |
| 1497 Here we provide several examples of Edebug specifications to show | |
| 1498 many of its capabilities. | |
| 1499 | |
|
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Change "special form" to "special operator" in our sources.
Aidan Kehoe <kehoea@parhasard.net>
parents:
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changeset
|
1500 A @code{let} special operator has a sequence of bindings and a body. Each |
| 428 | 1501 of the bindings is either a symbol or a sublist with a symbol and |
| 1502 optional value. In the specification below, notice the @code{gate} | |
| 1503 inside of the sublist to prevent backtracking. | |
| 1504 | |
| 1505 @example | |
| 1506 (def-edebug-spec let | |
| 1507 ((&rest | |
| 1508 &or symbolp (gate symbolp &optional form)) | |
| 1509 body)) | |
| 1510 @end example | |
| 1511 | |
| 1512 Edebug uses the following specifications for @code{defun} and | |
| 1513 @code{defmacro} and the associated argument list and @code{interactive} | |
| 1514 specifications. It is necessary to handle the expression argument of an | |
| 1515 interactive form specially since it is actually evaluated outside of the | |
| 1516 function body. | |
| 1517 | |
| 1518 @example | |
| 1519 (def-edebug-spec defmacro defun) ; @r{Indirect ref to @code{defun} spec} | |
| 444 | 1520 (def-edebug-spec defun |
| 1521 (&define name lambda-list | |
| 428 | 1522 [&optional stringp] ; @r{Match the doc string, if present.} |
| 1523 [&optional ("interactive" interactive)] | |
| 1524 def-body)) | |
| 1525 | |
| 1526 (def-edebug-spec lambda-list | |
| 1527 (([&rest arg] | |
| 1528 [&optional ["&optional" arg &rest arg]] | |
| 1529 &optional ["&rest" arg] | |
| 1530 ))) | |
| 1531 | |
| 1532 (def-edebug-spec interactive | |
| 1533 (&optional &or stringp def-form)) ; @r{Notice: @code{def-form}} | |
| 1534 @end example | |
| 1535 | |
| 1536 The specification for backquote below illustrates how to match | |
| 1537 dotted lists and use @code{nil} to terminate recursion. It also | |
| 1538 illustrates how components of a vector may be matched. (The actual | |
| 1539 specification provided by Edebug does not support dotted lists because | |
| 1540 doing so causes very deep recursion that could fail.) | |
| 1541 | |
| 1542 @example | |
| 1543 (def-edebug-spec ` (backquote-form)) ;; alias just for clarity | |
| 1544 | |
| 1545 (def-edebug-spec backquote-form | |
| 1546 (&or ([&or "," ",@@"] &or ("quote" backquote-form) form) | |
| 1547 (backquote-form . [&or nil backquote-form]) | |
| 1548 (vector &rest backquote-form) | |
| 1549 sexp)) | |
| 1550 @end example | |
| 1551 | |
| 1552 | |
| 1553 @node Edebug Options | |
| 1554 @subsection Edebug Options | |
| 1555 | |
| 1556 These options affect the behavior of Edebug: | |
| 1557 | |
| 1558 @defopt edebug-setup-hook | |
| 1559 Functions to call before Edebug is used. Each time it is set to a new | |
| 1560 value, Edebug will call those functions once and then | |
| 1561 @code{edebug-setup-hook} is reset to @code{nil}. You could use this to | |
| 1562 load up Edebug specifications associated with a package you are using | |
| 1563 but only when you also use Edebug. | |
| 1564 See @ref{Instrumenting}. | |
| 1565 @end defopt | |
| 1566 | |
| 1567 @defopt edebug-all-defs | |
| 1568 If non-@code{nil}, normal evaluation of any defining forms (e.g. | |
| 1569 @code{defun} and @code{defmacro}) will instrument them for Edebug. This | |
| 1570 applies to @code{eval-defun}, @code{eval-region}, and | |
| 1571 @code{eval-current-buffer}. | |
| 1572 | |
| 1573 Use the command @kbd{M-x edebug-all-defs} to toggle the value of | |
| 1574 this variable. You may want to make this variable local to each | |
| 1575 buffer by calling @code{(make-local-variable 'edebug-all-defs)} in your | |
| 1576 @code{emacs-lisp-mode-hook}. | |
| 1577 See @ref{Instrumenting}. | |
| 1578 @end defopt | |
| 1579 | |
| 1580 @defopt edebug-all-forms | |
| 1581 If non-@code{nil}, normal evaluation of any forms by @code{eval-defun}, | |
| 1582 @code{eval-region}, and @code{eval-current-buffer} will instrument them | |
| 1583 for Edebug. | |
| 1584 | |
| 1585 Use the command @kbd{M-x edebug-all-forms} to toggle the value of this | |
| 1586 option. | |
| 1587 See @ref{Instrumenting}. | |
| 1588 @end defopt | |
| 1589 | |
| 1590 @defopt edebug-save-windows | |
| 1591 If non-@code{nil}, save and restore window configuration on Edebug | |
| 1592 calls. It takes some time to do this, so if your program does not care | |
| 1593 what happens to data about windows, you may want to set this variable to | |
| 1594 @code{nil}. | |
| 1595 | |
| 1596 If the value is a list, only the listed windows are saved and | |
| 444 | 1597 restored. |
| 428 | 1598 |
| 1599 @kbd{M-x edebug-toggle-save-windows} may be used to change this variable. | |
| 1600 This command is bound to @kbd{W} in source code buffers. | |
| 1601 See @ref{Edebug Display Update}. | |
| 1602 @end defopt | |
| 1603 | |
| 1604 @defopt edebug-save-displayed-buffer-points | |
| 1605 If non-@code{nil}, save and restore point in all displayed buffers. | |
| 1606 This is necessary if you are debugging code that changes the point of a | |
| 1607 buffer which is displayed in a non-selected window. If Edebug or the | |
| 1608 user then selects the window, the buffer's point will be changed to the | |
| 1609 window's point. | |
| 1610 | |
| 1611 This is an expensive operation since it visits each window and therefore | |
| 1612 each displayed buffer twice for each Edebug activation, so it is best to | |
| 1613 avoid it if you can. | |
| 1614 See @ref{Edebug Display Update}. | |
| 1615 @end defopt | |
| 1616 | |
| 1617 | |
| 1618 @defopt edebug-initial-mode | |
| 1619 If this variable is non-@code{nil}, it specifies the initial execution | |
| 1620 mode for Edebug when it is first activated. Possible values are | |
| 1621 @code{step}, @code{next}, @code{go}, @code{Go-nonstop}, @code{trace}, | |
| 1622 @code{Trace-fast}, @code{continue}, and @code{Continue-fast}. | |
| 1623 | |
| 444 | 1624 The default value is @code{step}. |
| 428 | 1625 See @ref{Edebug Execution Modes}. |
| 1626 @end defopt | |
| 1627 | |
| 1628 @defopt edebug-trace | |
| 1629 @findex edebug-print-trace-before | |
| 1630 @findex edebug-print-trace-after | |
| 1631 Non-@code{nil} means display a trace of function entry and exit. | |
| 1632 Tracing output is displayed in a buffer named @samp{*edebug-trace*}, one | |
| 444 | 1633 function entry or exit per line, indented by the recursion level. |
| 428 | 1634 |
| 444 | 1635 The default value is @code{nil}. |
| 428 | 1636 |
| 1637 Also see @code{edebug-tracing}. | |
| 1638 See @ref{Tracing}. | |
| 1639 @end defopt | |
| 1640 | |
| 444 | 1641 @defopt edebug-test-coverage |
| 428 | 1642 If non-@code{nil}, Edebug tests coverage of all expressions debugged. |
| 1643 This is done by comparing the result of each expression | |
| 1644 with the previous result. Coverage is considered OK if two different | |
| 1645 results are found. So to sufficiently test the coverage of your code, | |
| 1646 try to execute it under conditions that evaluate all expressions more | |
| 1647 than once, and produce different results for each expression. | |
| 1648 | |
| 1649 Use @kbd{M-x edebug-display-freq-count} to display the frequency count | |
| 1650 and coverage information for a definition. | |
| 1651 See @ref{Coverage Testing}. | |
| 1652 @end defopt | |
| 1653 | |
| 444 | 1654 @defopt edebug-continue-kbd-macro |
| 428 | 1655 If non-@code{nil}, continue defining or executing any keyboard macro |
| 1656 that is executing outside of Edebug. Use this with caution since it is not | |
| 1657 debugged. | |
| 1658 See @ref{Edebug Execution Modes}. | |
| 1659 @end defopt | |
| 1660 | |
| 1661 @defopt edebug-print-length | |
| 1662 If non-@code{nil}, bind @code{print-length} to this while printing | |
| 1663 results in Edebug. The default value is @code{50}. | |
| 1664 See @ref{Printing in Edebug}. | |
| 1665 @end defopt | |
| 1666 | |
| 444 | 1667 @defopt edebug-print-level |
| 428 | 1668 If non-@code{nil}, bind @code{print-level} to this while printing |
| 1669 results in Edebug. The default value is @code{50}. | |
| 1670 @end defopt | |
| 1671 | |
| 444 | 1672 @defopt edebug-print-circle |
| 428 | 1673 If non-@code{nil}, bind @code{print-circle} to this while printing |
| 1674 results in Edebug. The default value is @code{nil}. | |
| 1675 @end defopt | |
| 1676 | |
| 1677 @defopt edebug-on-error | |
| 1678 @code{debug-on-error} is bound to this while Edebug is active. | |
| 1679 See @ref{Trapping Errors}. | |
| 1680 @end defopt | |
| 1681 | |
| 1682 @defopt edebug-on-quit | |
| 1683 @code{debug-on-quit} is bound to this while Edebug is active. | |
| 1684 See @ref{Trapping Errors}. | |
| 1685 @end defopt | |
| 1686 | |
| 1687 @defopt edebug-unwrap-results | |
| 1688 Non-@code{nil} if Edebug should unwrap results of expressions. | |
| 1689 This is useful when debugging macros where the results of expressions | |
| 1690 are instrumented expressions. But don't do this when results might be | |
| 1691 circular or an infinite loop will result. | |
| 1692 See @ref{Debugging Backquote}. | |
| 1693 @end defopt | |
| 1694 | |
| 1695 @defopt edebug-global-break-condition | |
| 1696 If non-@code{nil}, an expression to test for at every stop point. | |
| 444 | 1697 If the result is non-@code{nil}, then break. Errors are ignored. |
| 428 | 1698 See @ref{Global Break Condition}. |
| 1699 @end defopt |