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| 103 | .ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V' |
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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>. |