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129 | .\" ======================================================================== | |
130 | .\" | |
131 | .IX Title "B::Concise 3" | |
132 | .TH B::Concise 3 "2001-09-21" "perl v5.8.8" "Perl Programmers Reference Guide" | |
133 | .SH "NAME" | |
134 | B::Concise \- Walk Perl syntax tree, printing concise info about ops | |
135 | .SH "SYNOPSIS" | |
136 | .IX Header "SYNOPSIS" | |
137 | .Vb 1 | |
138 | \& perl -MO=Concise[,OPTIONS] foo.pl | |
139 | .Ve | |
140 | .PP | |
141 | .Vb 1 | |
142 | \& use B::Concise qw(set_style add_callback); | |
143 | .Ve | |
144 | .SH "DESCRIPTION" | |
145 | .IX Header "DESCRIPTION" | |
146 | This compiler backend prints the internal OPs of a Perl program's syntax | |
147 | tree in one of several space-efficient text formats suitable for debugging | |
148 | the inner workings of perl or other compiler backends. It can print OPs in | |
149 | the order they appear in the \s-1OP\s0 tree, in the order they will execute, or | |
150 | in a text approximation to their tree structure, and the format of the | |
151 | information displayed is customizable. Its function is similar to that of | |
152 | perl's \fB\-Dx\fR debugging flag or the \fBB::Terse\fR module, but it is more | |
153 | sophisticated and flexible. | |
154 | .SH "EXAMPLE" | |
155 | .IX Header "EXAMPLE" | |
156 | Here's an example of 2 outputs (aka 'renderings'), using the | |
157 | \&\-exec and \-basic (i.e. default) formatting conventions on the same code | |
158 | snippet. | |
159 | .PP | |
160 | .Vb 9 | |
161 | \& % perl -MO=Concise,-exec -e '$a = $b + 42' | |
162 | \& 1 <0> enter | |
163 | \& 2 <;> nextstate(main 1 -e:1) v | |
164 | \& 3 <#> gvsv[*b] s | |
165 | \& 4 <$> const[IV 42] s | |
166 | \& * 5 <2> add[t3] sK/2 | |
167 | \& 6 <#> gvsv[*a] s | |
168 | \& 7 <2> sassign vKS/2 | |
169 | \& 8 <@> leave[1 ref] vKP/REFC | |
170 | .Ve | |
171 | .PP | |
172 | Each line corresponds to an opcode. The opcode marked with '*' is used | |
173 | in a few examples below. | |
174 | .PP | |
175 | The 1st column is the op's sequence number, starting at 1, and is | |
176 | displayed in base 36 by default. This rendering is in \-exec (i.e. | |
177 | execution) order. | |
178 | .PP | |
179 | The symbol between angle brackets indicates the op's type, for | |
180 | example; <2> is a \s-1BINOP\s0, <@> a \s-1LISTOP\s0, and <#> is a \s-1PADOP\s0, which is | |
181 | used in threaded perls. (see \*(L"\s-1OP\s0 class abbreviations\*(R"). | |
182 | .PP | |
183 | The opname, as in \fB'add[t1]'\fR, which may be followed by op-specific | |
184 | information in parentheses or brackets (ex \fB'[t1]'\fR). | |
185 | .PP | |
186 | The op-flags (ex \fB'sK/2'\fR) follow, and are described in (\*(L"\s-1OP\s0 flags abbreviations\*(R"). | |
187 | .PP | |
188 | .Vb 11 | |
189 | \& % perl -MO=Concise -e '$a = $b + 42' | |
190 | \& 8 <@> leave[1 ref] vKP/REFC ->(end) | |
191 | \& 1 <0> enter ->2 | |
192 | \& 2 <;> nextstate(main 1 -e:1) v ->3 | |
193 | \& 7 <2> sassign vKS/2 ->8 | |
194 | \& * 5 <2> add[t1] sK/2 ->6 | |
195 | \& - <1> ex-rv2sv sK/1 ->4 | |
196 | \& 3 <$> gvsv(*b) s ->4 | |
197 | \& 4 <$> const(IV 42) s ->5 | |
198 | \& - <1> ex-rv2sv sKRM*/1 ->7 | |
199 | \& 6 <$> gvsv(*a) s ->7 | |
200 | .Ve | |
201 | .PP | |
202 | The default rendering is top\-down, so they're not in execution order. | |
203 | This form reflects the way the stack is used to parse and evaluate | |
204 | expressions; the add operates on the two terms below it in the tree. | |
205 | .PP | |
206 | Nullops appear as \f(CW\*(C`ex\-opname\*(C'\fR, where \fIopname\fR is an op that has been | |
207 | optimized away by perl. They're displayed with a sequence-number of | |
208 | \&'\-', because they are not executed (they don't appear in previous | |
209 | example), they're printed here because they reflect the parse. | |
210 | .PP | |
211 | The arrow points to the sequence number of the next op; they're not | |
212 | displayed in \-exec mode, for obvious reasons. | |
213 | .PP | |
214 | Note that because this rendering was done on a non-threaded perl, the | |
215 | PADOPs in the previous examples are now SVOPs, and some (but not all) | |
216 | of the square brackets have been replaced by round ones. This is a | |
217 | subtle feature to provide some visual distinction between renderings | |
218 | on threaded and un-threaded perls. | |
219 | .SH "OPTIONS" | |
220 | .IX Header "OPTIONS" | |
221 | Arguments that don't start with a hyphen are taken to be the names of | |
222 | subroutines to print the OPs of; if no such functions are specified, | |
223 | the main body of the program (outside any subroutines, and not | |
224 | including use'd or require'd files) is rendered. Passing \f(CW\*(C`BEGIN\*(C'\fR, | |
225 | \&\f(CW\*(C`CHECK\*(C'\fR, \f(CW\*(C`INIT\*(C'\fR, or \f(CW\*(C`END\*(C'\fR will cause all of the corresponding | |
226 | special blocks to be printed. | |
227 | .PP | |
228 | Options affect how things are rendered (ie printed). They're presented | |
229 | here by their visual effect, 1st being strongest. They're grouped | |
230 | according to how they interrelate; within each group the options are | |
231 | mutually exclusive (unless otherwise stated). | |
232 | .Sh "Options for Opcode Ordering" | |
233 | .IX Subsection "Options for Opcode Ordering" | |
234 | These options control the 'vertical display' of opcodes. The display | |
235 | \&'order' is also called 'mode' elsewhere in this document. | |
236 | .IP "\fB\-basic\fR" 4 | |
237 | .IX Item "-basic" | |
238 | Print OPs in the order they appear in the \s-1OP\s0 tree (a preorder | |
239 | traversal, starting at the root). The indentation of each \s-1OP\s0 shows its | |
240 | level in the tree, and the '\->' at the end of the line indicates the | |
241 | next opcode in execution order. This mode is the default, so the flag | |
242 | is included simply for completeness. | |
243 | .IP "\fB\-exec\fR" 4 | |
244 | .IX Item "-exec" | |
245 | Print OPs in the order they would normally execute (for the majority | |
246 | of constructs this is a postorder traversal of the tree, ending at the | |
247 | root). In most cases the \s-1OP\s0 that usually follows a given \s-1OP\s0 will | |
248 | appear directly below it; alternate paths are shown by indentation. In | |
249 | cases like loops when control jumps out of a linear path, a 'goto' | |
250 | line is generated. | |
251 | .IP "\fB\-tree\fR" 4 | |
252 | .IX Item "-tree" | |
253 | Print OPs in a text approximation of a tree, with the root of the tree | |
254 | at the left and 'left\-to\-right' order of children transformed into | |
255 | \&'top\-to\-bottom'. Because this mode grows both to the right and down, | |
256 | it isn't suitable for large programs (unless you have a very wide | |
257 | terminal). | |
258 | .Sh "Options for Line-Style" | |
259 | .IX Subsection "Options for Line-Style" | |
260 | These options select the line-style (or just style) used to render | |
261 | each opcode, and dictates what info is actually printed into each line. | |
262 | .IP "\fB\-concise\fR" 4 | |
263 | .IX Item "-concise" | |
264 | Use the author's favorite set of formatting conventions. This is the | |
265 | default, of course. | |
266 | .IP "\fB\-terse\fR" 4 | |
267 | .IX Item "-terse" | |
268 | Use formatting conventions that emulate the output of \fBB::Terse\fR. The | |
269 | basic mode is almost indistinguishable from the real \fBB::Terse\fR, and the | |
270 | exec mode looks very similar, but is in a more logical order and lacks | |
271 | curly brackets. \fBB::Terse\fR doesn't have a tree mode, so the tree mode | |
272 | is only vaguely reminiscent of \fBB::Terse\fR. | |
273 | .IP "\fB\-linenoise\fR" 4 | |
274 | .IX Item "-linenoise" | |
275 | Use formatting conventions in which the name of each \s-1OP\s0, rather than being | |
276 | written out in full, is represented by a one\- or two-character abbreviation. | |
277 | This is mainly a joke. | |
278 | .IP "\fB\-debug\fR" 4 | |
279 | .IX Item "-debug" | |
280 | Use formatting conventions reminiscent of \fBB::Debug\fR; these aren't | |
281 | very concise at all. | |
282 | .IP "\fB\-env\fR" 4 | |
283 | .IX Item "-env" | |
284 | Use formatting conventions read from the environment variables | |
285 | \&\f(CW\*(C`B_CONCISE_FORMAT\*(C'\fR, \f(CW\*(C`B_CONCISE_GOTO_FORMAT\*(C'\fR, and \f(CW\*(C`B_CONCISE_TREE_FORMAT\*(C'\fR. | |
286 | .Sh "Options for tree-specific formatting" | |
287 | .IX Subsection "Options for tree-specific formatting" | |
288 | .IP "\fB\-compact\fR" 4 | |
289 | .IX Item "-compact" | |
290 | Use a tree format in which the minimum amount of space is used for the | |
291 | lines connecting nodes (one character in most cases). This squeezes out | |
292 | a few precious columns of screen real estate. | |
293 | .IP "\fB\-loose\fR" 4 | |
294 | .IX Item "-loose" | |
295 | Use a tree format that uses longer edges to separate \s-1OP\s0 nodes. This format | |
296 | tends to look better than the compact one, especially in \s-1ASCII\s0, and is | |
297 | the default. | |
298 | .IP "\fB\-vt\fR" 4 | |
299 | .IX Item "-vt" | |
300 | Use tree connecting characters drawn from the \s-1VT100\s0 line-drawing set. | |
301 | This looks better if your terminal supports it. | |
302 | .IP "\fB\-ascii\fR" 4 | |
303 | .IX Item "-ascii" | |
304 | Draw the tree with standard \s-1ASCII\s0 characters like \f(CW\*(C`+\*(C'\fR and \f(CW\*(C`|\*(C'\fR. These don't | |
305 | look as clean as the \s-1VT100\s0 characters, but they'll work with almost any | |
306 | terminal (or the horizontal scrolling mode of \fIless\fR\|(1)) and are suitable | |
307 | for text documentation or email. This is the default. | |
308 | .PP | |
309 | These are pairwise exclusive, i.e. compact or loose, vt or ascii. | |
310 | .Sh "Options controlling sequence numbering" | |
311 | .IX Subsection "Options controlling sequence numbering" | |
312 | .IP "\fB\-base\fR\fIn\fR" 4 | |
313 | .IX Item "-basen" | |
314 | Print \s-1OP\s0 sequence numbers in base \fIn\fR. If \fIn\fR is greater than 10, the | |
315 | digit for 11 will be 'a', and so on. If \fIn\fR is greater than 36, the digit | |
316 | for 37 will be 'A', and so on until 62. Values greater than 62 are not | |
317 | currently supported. The default is 36. | |
318 | .IP "\fB\-bigendian\fR" 4 | |
319 | .IX Item "-bigendian" | |
320 | Print sequence numbers with the most significant digit first. This is the | |
321 | usual convention for Arabic numerals, and the default. | |
322 | .IP "\fB\-littleendian\fR" 4 | |
323 | .IX Item "-littleendian" | |
324 | Print seqence numbers with the least significant digit first. This is | |
325 | obviously mutually exclusive with bigendian. | |
326 | .Sh "Other options" | |
327 | .IX Subsection "Other options" | |
328 | These are pairwise exclusive. | |
329 | .IP "\fB\-main\fR" 4 | |
330 | .IX Item "-main" | |
331 | Include the main program in the output, even if subroutines were also | |
332 | specified. This rendering is normally suppressed when a subroutine | |
333 | name or reference is given. | |
334 | .IP "\fB\-nomain\fR" 4 | |
335 | .IX Item "-nomain" | |
336 | This restores the default behavior after you've changed it with '\-main' | |
337 | (it's not normally needed). If no subroutine name/ref is given, main is | |
338 | rendered, regardless of this flag. | |
339 | .IP "\fB\-nobanner\fR" 4 | |
340 | .IX Item "-nobanner" | |
341 | Renderings usually include a banner line identifying the function name | |
342 | or stringified subref. This suppresses the printing of the banner. | |
343 | .Sp | |
344 | \&\s-1TBC:\s0 Remove the stringified coderef; while it provides a 'cookie' for | |
345 | each function rendered, the cookies used should be 1,2,3.. not a | |
346 | random hex\-address. It also complicates string comparison of two | |
347 | different trees. | |
348 | .IP "\fB\-banner\fR" 4 | |
349 | .IX Item "-banner" | |
350 | restores default banner behavior. | |
351 | .IP "\fB\-banneris\fR => subref" 4 | |
352 | .IX Item "-banneris => subref" | |
353 | \&\s-1TBC:\s0 a hookpoint (and an option to set it) for a user-supplied | |
354 | function to produce a banner appropriate for users needs. It's not | |
355 | ideal, because the rendering-state variables, which are a natural | |
356 | candidate for use in concise.t, are unavailable to the user. | |
357 | .Sh "Option Stickiness" | |
358 | .IX Subsection "Option Stickiness" | |
359 | If you invoke Concise more than once in a program, you should know that | |
360 | the options are 'sticky'. This means that the options you provide in | |
361 | the first call will be remembered for the 2nd call, unless you | |
362 | re-specify or change them. | |
363 | .SH "ABBREVIATIONS" | |
364 | .IX Header "ABBREVIATIONS" | |
365 | The concise style uses symbols to convey maximum info with minimal | |
366 | clutter (like hex addresses). With just a little practice, you can | |
367 | start to see the flowers, not just the branches, in the trees. | |
368 | .Sh "\s-1OP\s0 class abbreviations" | |
369 | .IX Subsection "OP class abbreviations" | |
370 | These symbols appear before the op\-name, and indicate the | |
371 | B:: namespace that represents the ops in your Perl code. | |
372 | .PP | |
373 | .Vb 11 | |
374 | \& 0 OP (aka BASEOP) An OP with no children | |
375 | \& 1 UNOP An OP with one child | |
376 | \& 2 BINOP An OP with two children | |
377 | \& | LOGOP A control branch OP | |
378 | \& @ LISTOP An OP that could have lots of children | |
379 | \& / PMOP An OP with a regular expression | |
380 | \& $ SVOP An OP with an SV | |
381 | \& " PVOP An OP with a string | |
382 | \& { LOOP An OP that holds pointers for a loop | |
383 | \& ; COP An OP that marks the start of a statement | |
384 | \& # PADOP An OP with a GV on the pad | |
385 | .Ve | |
386 | .Sh "\s-1OP\s0 flags abbreviations" | |
387 | .IX Subsection "OP flags abbreviations" | |
388 | \&\s-1OP\s0 flags are either public or private. The public flags alter the | |
389 | behavior of each opcode in consistent ways, and are represented by 0 | |
390 | or more single characters. | |
391 | .PP | |
392 | .Vb 12 | |
393 | \& v OPf_WANT_VOID Want nothing (void context) | |
394 | \& s OPf_WANT_SCALAR Want single value (scalar context) | |
395 | \& l OPf_WANT_LIST Want list of any length (list context) | |
396 | \& Want is unknown | |
397 | \& K OPf_KIDS There is a firstborn child. | |
398 | \& P OPf_PARENS This operator was parenthesized. | |
399 | \& (Or block needs explicit scope entry.) | |
400 | \& R OPf_REF Certified reference. | |
401 | \& (Return container, not containee). | |
402 | \& M OPf_MOD Will modify (lvalue). | |
403 | \& S OPf_STACKED Some arg is arriving on the stack. | |
404 | \& * OPf_SPECIAL Do something weird for this op (see op.h) | |
405 | .Ve | |
406 | .PP | |
407 | Private flags, if any are set for an opcode, are displayed after a '/' | |
408 | .PP | |
409 | .Vb 2 | |
410 | \& 8 <@> leave[1 ref] vKP/REFC ->(end) | |
411 | \& 7 <2> sassign vKS/2 ->8 | |
412 | .Ve | |
413 | .PP | |
414 | They're opcode specific, and occur less often than the public ones, so | |
415 | they're represented by short mnemonics instead of single\-chars; see | |
416 | \&\fIop.h\fR for gory details, or try this quick 2\-liner: | |
417 | .PP | |
418 | .Vb 2 | |
419 | \& $> perl -MB::Concise -de 1 | |
420 | \& DB<1> |x \e%B::Concise::priv | |
421 | .Ve | |
422 | .SH "FORMATTING SPECIFICATIONS" | |
423 | .IX Header "FORMATTING SPECIFICATIONS" | |
424 | For each line-style ('concise', 'terse', 'linenoise', etc.) there are | |
425 | 3 format-specs which control how OPs are rendered. | |
426 | .PP | |
427 | The first is the 'default' format, which is used in both basic and exec | |
428 | modes to print all opcodes. The 2nd, goto\-format, is used in exec | |
429 | mode when branches are encountered. They're not real opcodes, and are | |
430 | inserted to look like a closing curly brace. The tree-format is tree | |
431 | specific. | |
432 | .PP | |
433 | When a line is rendered, the correct format-spec is copied and scanned | |
434 | for the following items; data is substituted in, and other | |
435 | manipulations like basic indenting are done, for each opcode rendered. | |
436 | .PP | |
437 | There are 3 kinds of items that may be populated; special patterns, | |
438 | #vars, and literal text, which is copied verbatim. (Yes, it's a set | |
439 | of s///g steps.) | |
440 | .Sh "Special Patterns" | |
441 | .IX Subsection "Special Patterns" | |
442 | These items are the primitives used to perform indenting, and to | |
443 | select text from amongst alternatives. | |
444 | .IP "\fB(x(\fR\fIexec_text\fR\fB;\fR\fIbasic_text\fR\fB)x)\fR" 4 | |
445 | .IX Item "(x(exec_text;basic_text)x)" | |
446 | Generates \fIexec_text\fR in exec mode, or \fIbasic_text\fR in basic mode. | |
447 | .IP "\fB(*(\fR\fItext\fR\fB)*)\fR" 4 | |
448 | .IX Item "(*(text)*)" | |
449 | Generates one copy of \fItext\fR for each indentation level. | |
450 | .IP "\fB(*(\fR\fItext1\fR\fB;\fR\fItext2\fR\fB)*)\fR" 4 | |
451 | .IX Item "(*(text1;text2)*)" | |
452 | Generates one fewer copies of \fItext1\fR than the indentation level, followed | |
453 | by one copy of \fItext2\fR if the indentation level is more than 0. | |
454 | .IP "\fB(?(\fR\fItext1\fR\fB#\fR\fIvar\fR\fIText2\fR\fB)?)\fR" 4 | |
455 | .IX Item "(?(text1#varText2)?)" | |
456 | If the value of \fIvar\fR is true (not empty or zero), generates the | |
457 | value of \fIvar\fR surrounded by \fItext1\fR and \fIText2\fR, otherwise | |
458 | nothing. | |
459 | .IP "\fB~\fR" 4 | |
460 | .IX Item "~" | |
461 | Any number of tildes and surrounding whitespace will be collapsed to | |
462 | a single space. | |
463 | .Sh "# Variables" | |
464 | .IX Subsection "# Variables" | |
465 | These #vars represent opcode properties that you may want as part of | |
466 | your rendering. The '#' is intended as a private sigil; a #var's | |
467 | value is interpolated into the style\-line, much like \*(L"read \f(CW$this\fR\*(R". | |
468 | .PP | |
469 | These vars take 3 forms: | |
470 | .IP "\fB#\fR\fIvar\fR" 4 | |
471 | .IX Item "#var" | |
472 | A property named 'var' is assumed to exist for the opcodes, and is | |
473 | interpolated into the rendering. | |
474 | .IP "\fB#\fR\fIvar\fR\fIN\fR" 4 | |
475 | .IX Item "#varN" | |
476 | Generates the value of \fIvar\fR, left justified to fill \fIN\fR spaces. | |
477 | Note that this means while you can have properties 'foo' and 'foo2', | |
478 | you cannot render 'foo2', but you could with 'foo2a'. You would be | |
479 | wise not to rely on this behavior going forward ;\-) | |
480 | .IP "\fB#\fR\fIVar\fR" 4 | |
481 | .IX Item "#Var" | |
482 | This ucfirst form of #var generates a tag-value form of itself for | |
483 | display; it converts '#Var' into a 'Var => #var' style, which is then | |
484 | handled as described above. (Imp\-note: #Vars cannot be used for | |
485 | conditional\-fills, because the => #var transform is done after the check | |
486 | for #Var's value). | |
487 | .PP | |
488 | The following variables are 'defined' by B::Concise; when they are | |
489 | used in a style, their respective values are plugged into the | |
490 | rendering of each opcode. | |
491 | .PP | |
492 | Only some of these are used by the standard styles, the others are | |
493 | provided for you to delve into optree mechanics, should you wish to | |
494 | add a new style (see \*(L"add_style\*(R" below) that uses them. You can | |
495 | also add new ones using \*(L"add_callback\*(R". | |
496 | .IP "\fB#addr\fR" 4 | |
497 | .IX Item "#addr" | |
498 | The address of the \s-1OP\s0, in hexadecimal. | |
499 | .IP "\fB#arg\fR" 4 | |
500 | .IX Item "#arg" | |
501 | The OP-specific information of the \s-1OP\s0 (such as the \s-1SV\s0 for an \s-1SVOP\s0, the | |
502 | non-local exit pointers for a \s-1LOOP\s0, etc.) enclosed in parentheses. | |
503 | .IP "\fB#class\fR" 4 | |
504 | .IX Item "#class" | |
505 | The B\-determined class of the \s-1OP\s0, in all caps. | |
506 | .IP "\fB#classsym\fR" 4 | |
507 | .IX Item "#classsym" | |
508 | A single symbol abbreviating the class of the \s-1OP\s0. | |
509 | .IP "\fB#coplabel\fR" 4 | |
510 | .IX Item "#coplabel" | |
511 | The label of the statement or block the \s-1OP\s0 is the start of, if any. | |
512 | .IP "\fB#exname\fR" 4 | |
513 | .IX Item "#exname" | |
514 | The name of the \s-1OP\s0, or 'ex\-foo' if the \s-1OP\s0 is a null that used to be a foo. | |
515 | .IP "\fB#extarg\fR" 4 | |
516 | .IX Item "#extarg" | |
517 | The target of the \s-1OP\s0, or nothing for a nulled \s-1OP\s0. | |
518 | .IP "\fB#firstaddr\fR" 4 | |
519 | .IX Item "#firstaddr" | |
520 | The address of the \s-1OP\s0's first child, in hexadecimal. | |
521 | .IP "\fB#flags\fR" 4 | |
522 | .IX Item "#flags" | |
523 | The \s-1OP\s0's flags, abbreviated as a series of symbols. | |
524 | .IP "\fB#flagval\fR" 4 | |
525 | .IX Item "#flagval" | |
526 | The numeric value of the \s-1OP\s0's flags. | |
527 | .IP "\fB#hyphseq\fR" 4 | |
528 | .IX Item "#hyphseq" | |
529 | The sequence number of the \s-1OP\s0, or a hyphen if it doesn't have one. | |
530 | .IP "\fB#label\fR" 4 | |
531 | .IX Item "#label" | |
532 | \&'\s-1NEXT\s0', '\s-1LAST\s0', or '\s-1REDO\s0' if the \s-1OP\s0 is a target of one of those in exec | |
533 | mode, or empty otherwise. | |
534 | .IP "\fB#lastaddr\fR" 4 | |
535 | .IX Item "#lastaddr" | |
536 | The address of the \s-1OP\s0's last child, in hexadecimal. | |
537 | .IP "\fB#name\fR" 4 | |
538 | .IX Item "#name" | |
539 | The \s-1OP\s0's name. | |
540 | .IP "\fB#NAME\fR" 4 | |
541 | .IX Item "#NAME" | |
542 | The \s-1OP\s0's name, in all caps. | |
543 | .IP "\fB#next\fR" 4 | |
544 | .IX Item "#next" | |
545 | The sequence number of the \s-1OP\s0's next \s-1OP\s0. | |
546 | .IP "\fB#nextaddr\fR" 4 | |
547 | .IX Item "#nextaddr" | |
548 | The address of the \s-1OP\s0's next \s-1OP\s0, in hexadecimal. | |
549 | .IP "\fB#noise\fR" 4 | |
550 | .IX Item "#noise" | |
551 | A one\- or two-character abbreviation for the \s-1OP\s0's name. | |
552 | .IP "\fB#private\fR" 4 | |
553 | .IX Item "#private" | |
554 | The \s-1OP\s0's private flags, rendered with abbreviated names if possible. | |
555 | .IP "\fB#privval\fR" 4 | |
556 | .IX Item "#privval" | |
557 | The numeric value of the \s-1OP\s0's private flags. | |
558 | .IP "\fB#seq\fR" 4 | |
559 | .IX Item "#seq" | |
560 | The sequence number of the \s-1OP\s0. Note that this is a sequence number | |
561 | generated by B::Concise. | |
562 | .IP "\fB#seqnum\fR" 4 | |
563 | .IX Item "#seqnum" | |
564 | 5.8.x and earlier only. 5.9 and later do not provide this. | |
565 | .Sp | |
566 | The real sequence number of the \s-1OP\s0, as a regular number and not adjusted | |
567 | to be relative to the start of the real program. (This will generally be | |
568 | a fairly large number because all of \fBB::Concise\fR is compiled before | |
569 | your program is). | |
570 | .IP "\fB#opt\fR" 4 | |
571 | .IX Item "#opt" | |
572 | Whether or not the op has been optimised by the peephole optimiser. | |
573 | .Sp | |
574 | Only available in 5.9 and later. | |
575 | .IP "\fB#static\fR" 4 | |
576 | .IX Item "#static" | |
577 | Whether or not the op is statically defined. This flag is used by the | |
578 | B::C compiler backend and indicates that the op should not be freed. | |
579 | .Sp | |
580 | Only available in 5.9 and later. | |
581 | .IP "\fB#sibaddr\fR" 4 | |
582 | .IX Item "#sibaddr" | |
583 | The address of the \s-1OP\s0's next youngest sibling, in hexadecimal. | |
584 | .IP "\fB#svaddr\fR" 4 | |
585 | .IX Item "#svaddr" | |
586 | The address of the \s-1OP\s0's \s-1SV\s0, if it has an \s-1SV\s0, in hexadecimal. | |
587 | .IP "\fB#svclass\fR" 4 | |
588 | .IX Item "#svclass" | |
589 | The class of the \s-1OP\s0's \s-1SV\s0, if it has one, in all caps (e.g., '\s-1IV\s0'). | |
590 | .IP "\fB#svval\fR" 4 | |
591 | .IX Item "#svval" | |
592 | The value of the \s-1OP\s0's \s-1SV\s0, if it has one, in a short human-readable format. | |
593 | .IP "\fB#targ\fR" 4 | |
594 | .IX Item "#targ" | |
595 | The numeric value of the \s-1OP\s0's targ. | |
596 | .IP "\fB#targarg\fR" 4 | |
597 | .IX Item "#targarg" | |
598 | The name of the variable the \s-1OP\s0's targ refers to, if any, otherwise the | |
599 | letter t followed by the \s-1OP\s0's targ in decimal. | |
600 | .IP "\fB#targarglife\fR" 4 | |
601 | .IX Item "#targarglife" | |
602 | Same as \fB#targarg\fR, but followed by the \s-1COP\s0 sequence numbers that delimit | |
603 | the variable's lifetime (or 'end' for a variable in an open scope) for a | |
604 | variable. | |
605 | .IP "\fB#typenum\fR" 4 | |
606 | .IX Item "#typenum" | |
607 | The numeric value of the \s-1OP\s0's type, in decimal. | |
608 | .SH "Using B::Concise outside of the O framework" | |
609 | .IX Header "Using B::Concise outside of the O framework" | |
610 | The common (and original) usage of B::Concise was for command-line | |
611 | renderings of simple code, as given in \s-1EXAMPLE\s0. But you can also use | |
612 | \&\fBB::Concise\fR from your code, and call \fIcompile()\fR directly, and | |
613 | repeatedly. By doing so, you can avoid the compile-time only | |
614 | operation of O.pm, and even use the debugger to step through | |
615 | \&\fIB::Concise::compile()\fR itself. | |
616 | .PP | |
617 | Once you're doing this, you may alter Concise output by adding new | |
618 | rendering styles, and by optionally adding callback routines which | |
619 | populate new variables, if such were referenced from those (just | |
620 | added) styles. | |
621 | .Sh "Example: Altering Concise Renderings" | |
622 | .IX Subsection "Example: Altering Concise Renderings" | |
623 | .Vb 9 | |
624 | \& use B::Concise qw(set_style add_callback); | |
625 | \& add_style($yourStyleName => $defaultfmt, $gotofmt, $treefmt); | |
626 | \& add_callback | |
627 | \& ( sub { | |
628 | \& my ($h, $op, $format, $level, $stylename) = @_; | |
629 | \& $h->{variable} = some_func($op); | |
630 | \& }); | |
631 | \& $walker = B::Concise::compile(@options,@subnames,@subrefs); | |
632 | \& $walker->(); | |
633 | .Ve | |
634 | .Sh "\fIset_style()\fP" | |
635 | .IX Subsection "set_style()" | |
636 | \&\fBset_style\fR accepts 3 arguments, and updates the three format-specs | |
637 | comprising a line-style (basic\-exec, goto, tree). It has one minor | |
638 | drawback though; it doesn't register the style under a new name. This | |
639 | can become an issue if you render more than once and switch styles. | |
640 | Thus you may prefer to use \fIadd_style()\fR and/or \fIset_style_standard()\fR | |
641 | instead. | |
642 | .Sh "set_style_standard($name)" | |
643 | .IX Subsection "set_style_standard($name)" | |
644 | This restores one of the standard line\-styles: \f(CW\*(C`terse\*(C'\fR, \f(CW\*(C`concise\*(C'\fR, | |
645 | \&\f(CW\*(C`linenoise\*(C'\fR, \f(CW\*(C`debug\*(C'\fR, \f(CW\*(C`env\*(C'\fR, into effect. It also accepts style | |
646 | names previously defined with \fIadd_style()\fR. | |
647 | .Sh "\fIadd_style()\fP" | |
648 | .IX Subsection "add_style()" | |
649 | This subroutine accepts a new style name and three style arguments as | |
650 | above, and creates, registers, and selects the newly named style. It is | |
651 | an error to re-add a style; call \fIset_style_standard()\fR to switch between | |
652 | several styles. | |
653 | .Sh "\fIadd_callback()\fP" | |
654 | .IX Subsection "add_callback()" | |
655 | If your newly minted styles refer to any new #variables, you'll need | |
656 | to define a callback subroutine that will populate (or modify) those | |
657 | variables. They are then available for use in the style you've | |
658 | chosen. | |
659 | .PP | |
660 | The callbacks are called for each opcode visited by Concise, in the | |
661 | same order as they are added. Each subroutine is passed five | |
662 | parameters. | |
663 | .PP | |
664 | .Vb 6 | |
665 | \& 1. A hashref, containing the variable names and values which are | |
666 | \& populated into the report-line for the op | |
667 | \& 2. the op, as a B<B::OP> object | |
668 | \& 3. a reference to the format string | |
669 | \& 4. the formatting (indent) level | |
670 | \& 5. the selected stylename | |
671 | .Ve | |
672 | .PP | |
673 | To define your own variables, simply add them to the hash, or change | |
674 | existing values if you need to. The level and format are passed in as | |
675 | references to scalars, but it is unlikely that they will need to be | |
676 | changed or even used. | |
677 | .Sh "Running \fIB::Concise::compile()\fP" | |
678 | .IX Subsection "Running B::Concise::compile()" | |
679 | \&\fBcompile\fR accepts options as described above in \*(L"\s-1OPTIONS\s0\*(R", and | |
680 | arguments, which are either coderefs, or subroutine names. | |
681 | .PP | |
682 | It constructs and returns a \f(CW$treewalker\fR coderef, which when invoked, | |
683 | traverses, or walks, and renders the optrees of the given arguments to | |
684 | \&\s-1STDOUT\s0. You can reuse this, and can change the rendering style used | |
685 | each time; thereafter the coderef renders in the new style. | |
686 | .PP | |
687 | \&\fBwalk_output\fR lets you change the print destination from \s-1STDOUT\s0 to | |
688 | another open filehandle, or into a string passed as a ref (unless | |
689 | you've built perl with \-Uuseperlio). | |
690 | .PP | |
691 | .Vb 7 | |
692 | \& my $walker = B::Concise::compile('-terse','aFuncName', \e&aSubRef); # 1 | |
693 | \& walk_output(\emy $buf); | |
694 | \& $walker->(); # 1 renders -terse | |
695 | \& set_style_standard('concise'); # 2 | |
696 | \& $walker->(); # 2 renders -concise | |
697 | \& $walker->(@new); # 3 renders whatever | |
698 | \& print "3 different renderings: terse, concise, and @new: $buf\en"; | |
699 | .Ve | |
700 | .PP | |
701 | When \f(CW$walker\fR is called, it traverses the subroutines supplied when it | |
702 | was created, and renders them using the current style. You can change | |
703 | the style afterwards in several different ways: | |
704 | .PP | |
705 | .Vb 3 | |
706 | \& 1. call C<compile>, altering style or mode/order | |
707 | \& 2. call C<set_style_standard> | |
708 | \& 3. call $walker, passing @new options | |
709 | .Ve | |
710 | .PP | |
711 | Passing new options to the \f(CW$walker\fR is the easiest way to change | |
712 | amongst any pre-defined styles (the ones you add are automatically | |
713 | recognized as options), and is the only way to alter rendering order | |
714 | without calling compile again. Note however that rendering state is | |
715 | still shared amongst multiple \f(CW$walker\fR objects, so they must still be | |
716 | used in a coordinated manner. | |
717 | .Sh "\fIB::Concise::reset_sequence()\fP" | |
718 | .IX Subsection "B::Concise::reset_sequence()" | |
719 | This function (not exported) lets you reset the sequence numbers (note | |
720 | that they're numbered arbitrarily, their goal being to be human | |
721 | readable). Its purpose is mostly to support testing, i.e. to compare | |
722 | the concise output from two identical anonymous subroutines (but | |
723 | different instances). Without the reset, B::Concise, seeing that | |
724 | they're separate optrees, generates different sequence numbers in | |
725 | the output. | |
726 | .Sh "Errors" | |
727 | .IX Subsection "Errors" | |
728 | Errors in rendering (non\-existent function\-name, non-existent coderef) | |
729 | are written to the \s-1STDOUT\s0, or wherever you've set it via | |
730 | \&\fIwalk_output()\fR. | |
731 | .PP | |
732 | Errors using the various *style* calls, and bad args to \fIwalk_output()\fR, | |
733 | result in \fIdie()\fR. Use an eval if you wish to catch these errors and | |
734 | continue processing. | |
735 | .SH "AUTHOR" | |
736 | .IX Header "AUTHOR" | |
737 | Stephen McCamant, <smcc@CSUA.Berkeley.EDU>. |