2 # Copyright (C) 2000-2003 Stephen McCamant. All rights reserved.
3 # This program is free software; you can redistribute and/or modify it
4 # under the same terms as Perl itself.
6 # Note: we need to keep track of how many use declarations/BEGIN
7 # blocks this module uses, so we can avoid printing them when user
8 # asks for the BEGIN blocks in her program. Update the comments and
9 # the count in concise_specials if you add or delete one. The
10 # -MO=Concise counts as use #1.
13 use warnings; # uses #3 and #4, since warnings uses Carp
15 use Exporter (); # use #5
17 our $VERSION = "0.63";
18 our @ISA = qw(Exporter);
19 our @EXPORT_OK = qw( set_style set_style_standard add_callback
20 concise_subref concise_cv concise_main
21 add_style walk_output compile reset_sequence );
23 ( io => [qw( walk_output compile reset_sequence )],
24 style => [qw( add_style set_style_standard )],
25 cb => [qw( add_callback )],
26 mech => [qw( concise_subref concise_cv concise_main )], );
29 use B qw(class ppname main_start main_root main_cv cstring svref_2object
30 SVf_IOK SVf_NOK SVf_POK SVf_IVisUV SVf_FAKE OPf_KIDS OPf_SPECIAL
35 ["(?(#label =>\n)?)(*( )*)#class (#addr) #name (?([#targ])?) "
36 . "#svclass~(?((#svaddr))?)~#svval~(?(label \"#coplabel\")?)\n",
37 "(*( )*)goto #class (#addr)\n",
40 ["#hyphseq2 (*( (x( ;)x))*)<#classsym> "
41 . "#exname#arg(?([#targarglife])?)~#flags(?(/#private)?)(x(;~->#next)x)\n"
42 , " (*( )*) goto #seq\n",
43 "(?(<#seq>)?)#exname#arg(?([#targarglife])?)"],
45 ["(x(;(*( )*))x)#noise#arg(?([#targarg])?)(x( ;\n)x)",
47 "(?(#seq)?)#noise#arg(?([#targarg])?)"],
49 ["#class (#addr)\n\top_next\t\t#nextaddr\n\top_sibling\t#sibaddr\n\t"
50 . "op_ppaddr\tPL_ppaddr[OP_#NAME]\n\top_type\t\t#typenum\n"
51 . "\top_flags\t#flagval\n\top_private\t#privval\n"
52 . "(?(\top_first\t#firstaddr\n)?)(?(\top_last\t\t#lastaddr\n)?)"
53 . "(?(\top_sv\t\t#svaddr\n)?)",
56 "env" => [$ENV{B_CONCISE_FORMAT}, $ENV{B_CONCISE_GOTO_FORMAT},
57 $ENV{B_CONCISE_TREE_FORMAT}],
60 # Renderings, ie how Concise prints, is controlled by these vars
62 our $stylename; # selects current style from %style
63 my $order = "basic"; # how optree is walked & printed: basic, exec, tree
65 # rendering mechanics:
66 # these 'formats' are the line-rendering templates
67 # they're updated from %style when $stylename changes
68 my ($format, $gotofmt, $treefmt);
71 my $base = 36; # how <sequence#> is displayed
72 my $big_endian = 1; # more <sequence#> display
73 my $tree_style = 0; # tree-order details
74 my $banner = 1; # print banner before optree is traversed
75 my $do_main = 0; # force printing of main routine
77 # another factor: can affect all styles!
78 our @callbacks; # allow external management
80 set_style_standard("concise");
86 ($format, $gotofmt, $treefmt) = @_;
87 #warn "set_style: deprecated, use set_style_standard instead\n"; # someday
88 die "expecting 3 style-format args\n" unless @_ == 3;
92 my ($newstyle,@args) = @_;
93 die "style '$newstyle' already exists, choose a new name\n"
94 if exists $style{$newstyle};
95 die "expecting 3 style-format args\n" unless @args == 3;
96 $style{$newstyle} = [@args];
97 $stylename = $newstyle; # update rendering state
100 sub set_style_standard {
101 ($stylename) = @_; # update rendering state
102 die "err: style '$stylename' unknown\n" unless exists $style{$stylename};
103 set_style(@{$style{$stylename}});
110 # output handle, used with all Concise-output printing
111 our $walkHandle; # public for your convenience
112 BEGIN { $walkHandle = \*STDOUT }
114 sub walk_output { # updates $walkHandle
116 return $walkHandle unless $handle; # allow use as accessor
118 if (ref $handle eq 'SCALAR') {
120 die "no perlio in this build, can't call walk_output (\\\$scalar)\n"
121 unless $Config::Config{useperlio};
122 # in 5.8+, open(FILEHANDLE,MODE,REFERENCE) writes to string
123 open my $tmp, '>', $handle; # but cant re-set existing STDOUT
124 $walkHandle = $tmp; # so use my $tmp as intermediate var
127 my $iotype = ref $handle;
128 die "expecting argument/object that can print\n"
129 unless $iotype eq 'GLOB' or $iotype and $handle->can('print');
130 $walkHandle = $handle;
134 my($order, $coderef) = @_;
135 my $codeobj = svref_2object($coderef);
137 return concise_stashref(@_)
138 unless ref $codeobj eq 'B::CV';
139 concise_cv_obj($order, $codeobj);
142 sub concise_stashref {
144 foreach my $k (sort keys %$h) {
146 my $coderef = *s{CODE} or next;
148 print "FUNC: ", *s, "\n";
149 my $codeobj = svref_2object($coderef);
150 next unless ref $codeobj eq 'B::CV';
151 eval { concise_cv_obj($order, $codeobj) }
152 or warn "err $@ on $codeobj";
156 # This should have been called concise_subref, but it was exported
157 # under this name in versions before 0.56
158 sub concise_cv { concise_subref(@_); }
161 my ($order, $cv) = @_;
163 die "err: coderef has no START\n" if class($cv->START) eq "NULL";
164 sequence($cv->START);
165 if ($order eq "exec") {
166 walk_exec($cv->START);
167 } elsif ($order eq "basic") {
168 walk_topdown($cv->ROOT, sub { $_[0]->concise($_[1]) }, 0);
170 print $walkHandle tree($cv->ROOT, 0);
176 sequence(main_start);
178 if ($order eq "exec") {
179 return if class(main_start) eq "NULL";
180 walk_exec(main_start);
181 } elsif ($order eq "tree") {
182 return if class(main_root) eq "NULL";
183 print $walkHandle tree(main_root, 0);
184 } elsif ($order eq "basic") {
185 return if class(main_root) eq "NULL";
186 walk_topdown(main_root,
187 sub { $_[0]->concise($_[1]) }, 0);
191 sub concise_specials {
192 my($name, $order, @cv_s) = @_;
194 if ($name eq "BEGIN") {
195 splice(@cv_s, 0, 7); # skip 7 BEGIN blocks in this file
196 } elsif ($name eq "CHECK") {
197 pop @cv_s; # skip the CHECK block that calls us
200 print $walkHandle "$name $i:\n";
202 concise_cv_obj($order, $cv);
206 my $start_sym = "\e(0"; # "\cN" sometimes also works
207 my $end_sym = "\e(B"; # "\cO" respectively
209 my @tree_decorations =
210 ([" ", "--", "+-", "|-", "| ", "`-", "-", 1],
211 [" ", "-", "+", "+", "|", "`", "", 0],
212 [" ", map("$start_sym$_$end_sym", "qq", "wq", "tq", "x ", "mq", "q"), 1],
213 [" ", map("$start_sym$_$end_sym", "q", "w", "t", "x", "m"), "", 0],
218 # set rendering state from options and args
219 my @options = grep(/^-/, @_);
220 my @args = grep(!/^-/, @_);
221 for my $o (@options) {
223 if ($o eq "-basic") {
225 } elsif ($o eq "-exec") {
227 } elsif ($o eq "-tree") {
231 elsif ($o eq "-compact") {
233 } elsif ($o eq "-loose") {
235 } elsif ($o eq "-vt") {
237 } elsif ($o eq "-ascii") {
241 elsif ($o =~ /^-base(\d+)$/) {
243 } elsif ($o eq "-bigendian") {
245 } elsif ($o eq "-littleendian") {
248 elsif ($o eq "-nobanner") {
250 } elsif ($o eq "-banner") {
253 elsif ($o eq "-main") {
255 } elsif ($o eq "-nomain") {
259 elsif (exists $style{substr($o, 1)}) {
260 $stylename = substr($o, 1);
261 set_style_standard($stylename);
263 warn "Option $o unrecognized";
270 my (@args) = compileOpts(@_);
272 my @newargs = compileOpts(@_); # accept new rendering options
273 warn "disregarding non-options: @newargs\n" if @newargs;
275 for my $objname (@args) {
277 if ($objname eq "BEGIN") {
278 concise_specials("BEGIN", $order,
279 B::begin_av->isa("B::AV") ?
280 B::begin_av->ARRAY : ());
281 } elsif ($objname eq "INIT") {
282 concise_specials("INIT", $order,
283 B::init_av->isa("B::AV") ?
284 B::init_av->ARRAY : ());
285 } elsif ($objname eq "CHECK") {
286 concise_specials("CHECK", $order,
287 B::check_av->isa("B::AV") ?
288 B::check_av->ARRAY : ());
289 } elsif ($objname eq "END") {
290 concise_specials("END", $order,
291 B::end_av->isa("B::AV") ?
292 B::end_av->ARRAY : ());
295 # convert function names to subrefs
298 print $walkHandle "B::Concise::compile($objname)\n"
302 $objname = "main::" . $objname unless $objname =~ /::/;
303 print $walkHandle "$objname:\n";
305 die "err: unknown function ($objname)\n"
306 unless *{$objname}{CODE};
307 $objref = \&$objname;
309 concise_subref($order, $objref);
312 if (!@args or $do_main) {
313 print $walkHandle "main program:\n" if $do_main;
314 concise_main($order);
316 return @args; # something
321 my $lastnext; # remembers op-chain, used to insert gotos
323 my %opclass = ('OP' => "0", 'UNOP' => "1", 'BINOP' => "2", 'LOGOP' => "|",
324 'LISTOP' => "@", 'PMOP' => "/", 'SVOP' => "\$", 'GVOP' => "*",
325 'PVOP' => '"', 'LOOP' => "{", 'COP' => ";", 'PADOP' => "#");
327 no warnings 'qw'; # "Possible attempt to put comments..."; use #7
329 qw'# () sc ( @? 1 $* gv *{ m$ m@ m% m? p/ *$ $ $# & a& pt \\ s\\ rf bl
330 ` *? <> ?? ?/ r/ c/ // qr s/ /c y/ = @= C sC Cp sp df un BM po +1 +I
331 -1 -I 1+ I+ 1- I- ** * i* / i/ %$ i% x + i+ - i- . " << >> < i<
332 > i> <= i, >= i. == i= != i! <? i? s< s> s, s. s= s! s? b& b^ b| -0 -i
333 ! ~ a2 si cs rd sr e^ lg sq in %x %o ab le ss ve ix ri sf FL od ch cy
334 uf lf uc lc qm @ [f [ @[ eh vl ky dl ex % ${ @{ uk pk st jn ) )[ a@
335 a% sl +] -] [- [+ so rv GS GW MS MW .. f. .f && || ^^ ?: &= |= -> s{ s}
336 v} ca wa di rs ;; ; ;d }{ { } {} f{ it {l l} rt }l }n }r dm }g }e ^o
337 ^c ^| ^# um bm t~ u~ ~d DB db ^s se ^g ^r {w }w pf pr ^O ^K ^R ^W ^d ^v
338 ^e ^t ^k t. fc ic fl .s .p .b .c .l .a .h g1 s1 g2 s2 ?. l? -R -W -X -r
339 -w -x -e -o -O -z -s -M -A -C -S -c -b -f -d -p -l -u -g -k -t -T -B cd
340 co cr u. cm ut r. l@ s@ r@ mD uD oD rD tD sD wD cD f$ w$ p$ sh e$ k$ g3
341 g4 s4 g5 s5 T@ C@ L@ G@ A@ S@ Hg Hc Hr Hw Mg Mc Ms Mr Sg Sc So rq do {e
342 e} {t t} g6 G6 6e g7 G7 7e g8 G8 8e g9 G9 9e 6s 7s 8s 9s 6E 7E 8E 9E Pn
343 Pu GP SP EP Gn Gg GG SG EG g0 c$ lk t$ ;s n> // /= CO';
345 my $chars = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
350 push @v, "v" if ($x & 3) == 1;
351 push @v, "s" if ($x & 3) == 2;
352 push @v, "l" if ($x & 3) == 3;
353 push @v, "K" if $x & 4;
354 push @v, "P" if $x & 8;
355 push @v, "R" if $x & 16;
356 push @v, "M" if $x & 32;
357 push @v, "S" if $x & 64;
358 push @v, "*" if $x & 128;
364 return "-" . base_n(-$x) if $x < 0;
366 do { $str .= substr($chars, $x % $base, 1) } while $x = int($x / $base);
367 $str = reverse $str if $big_endian;
383 return "-" if not exists $sequence_num{$$op};
384 return base_n($sequence_num{$$op});
388 my($op, $sub, $level) = @_;
390 if ($op->flags & OPf_KIDS) {
391 for (my $kid = $op->first; $$kid; $kid = $kid->sibling) {
392 walk_topdown($kid, $sub, $level + 1);
395 if (class($op) eq "PMOP") {
396 my $maybe_root = $op->pmreplroot;
397 if (ref($maybe_root) and $maybe_root->isa("B::OP")) {
398 # It really is the root of the replacement, not something
399 # else stored here for lack of space elsewhere
400 walk_topdown($maybe_root, $sub, $level + 1);
406 my($ar, $level) = @_;
408 if (ref($l) eq "ARRAY") {
409 walklines($l, $level + 1);
417 my($top, $level) = @_;
420 my @todo = ([$top, \@lines]);
421 while (@todo and my($op, $targ) = @{shift @todo}) {
422 for (; $$op; $op = $op->next) {
423 last if $opsseen{$$op}++;
425 my $name = $op->name;
426 if (class($op) eq "LOGOP") {
429 push @todo, [$op->other, $ar];
430 } elsif ($name eq "subst" and $ {$op->pmreplstart}) {
433 push @todo, [$op->pmreplstart, $ar];
434 } elsif ($name =~ /^enter(loop|iter)$/) {
435 $labels{${$op->nextop}} = "NEXT";
436 $labels{${$op->lastop}} = "LAST";
437 $labels{${$op->redoop}} = "REDO";
441 walklines(\@lines, 0);
444 # The structure of this routine is purposely modeled after op.c's peep()
448 return if class($op) eq "NULL" or exists $sequence_num{$$op};
449 for (; $$op; $op = $op->next) {
450 last if exists $sequence_num{$$op};
451 my $name = $op->name;
452 if ($name =~ /^(null|scalar|lineseq|scope)$/) {
453 next if $oldop and $ {$op->next};
455 $sequence_num{$$op} = $seq_max++;
456 if (class($op) eq "LOGOP") {
457 my $other = $op->other;
458 $other = $other->next while $other->name eq "null";
460 } elsif (class($op) eq "LOOP") {
461 my $redoop = $op->redoop;
462 $redoop = $redoop->next while $redoop->name eq "null";
464 my $nextop = $op->nextop;
465 $nextop = $nextop->next while $nextop->name eq "null";
467 my $lastop = $op->lastop;
468 $lastop = $lastop->next while $lastop->name eq "null";
470 } elsif ($name eq "subst" and $ {$op->pmreplstart}) {
471 my $replstart = $op->pmreplstart;
472 $replstart = $replstart->next while $replstart->name eq "null";
473 sequence($replstart);
480 sub fmt_line { # generate text-line for op.
481 my($hr, $op, $text, $level) = @_;
483 $_->($hr, $op, \$text, \$level, $stylename) for @callbacks;
485 return '' if $hr->{SKIP}; # suppress line if a callback said so
486 return '' if $hr->{goto} and $hr->{goto} eq '-'; # no goto nowhere
488 # spec: (?(text1#varText2)?)
489 $text =~ s/\(\?\(([^\#]*?)\#(\w+)([^\#]*?)\)\?\)/
490 $hr->{$2} ? $1.$hr->{$2}.$3 : ""/eg;
492 # spec: (x(exec_text;basic_text)x)
493 $text =~ s/\(x\((.*?);(.*?)\)x\)/$order eq "exec" ? $1 : $2/egs;
496 $text =~ s/\(\*\(([^;]*?)\)\*\)/$1 x $level/egs;
498 # spec: (*(text1;text2)*)
499 $text =~ s/\(\*\((.*?);(.*?)\)\*\)/$1 x ($level - 1) . $2 x ($level>0)/egs;
501 # convert #Var to tag=>val form: Var\t#var
502 $text =~ s/\#([A-Z][a-z]+)(\d+)?/\t\u$1\t\L#$1$2/gs;
505 $text =~ s/\#([a-zA-Z]+)(\d+)/sprintf("%-$2s", $hr->{$1})/eg;
507 $text =~ s/\#([a-zA-Z]+)/$hr->{$1}/eg; # populate #var's
508 $text =~ s/[ \t]*~+[ \t]*/ /g; # squeeze tildes
510 return "$text\n" if $text ne "";
511 return $text; # suppress empty lines
515 $priv{$_}{128} = "LVINTRO"
516 for ("pos", "substr", "vec", "threadsv", "gvsv", "rv2sv", "rv2hv", "rv2gv",
517 "rv2av", "rv2arylen", "aelem", "helem", "aslice", "hslice", "padsv",
518 "padav", "padhv", "enteriter");
519 $priv{$_}{64} = "REFC" for ("leave", "leavesub", "leavesublv", "leavewrite");
520 $priv{"aassign"}{64} = "COMMON";
521 $priv{"aassign"}{32} = "PHASH" if $] < 5.009;
522 $priv{"sassign"}{64} = "BKWARD";
523 $priv{$_}{64} = "RTIME" for ("match", "subst", "substcont");
524 @{$priv{"trans"}}{1,2,4,8,16,64} = ("<UTF", ">UTF", "IDENT", "SQUASH", "DEL",
526 $priv{"repeat"}{64} = "DOLIST";
527 $priv{"leaveloop"}{64} = "CONT";
528 @{$priv{$_}}{32,64,96} = ("DREFAV", "DREFHV", "DREFSV")
529 for (qw(rv2gv rv2sv padsv aelem helem));
530 $priv{"entersub"}{16} = "DBG";
531 $priv{"entersub"}{32} = "TARG";
532 @{$priv{$_}}{4,8,128} = ("INARGS","AMPER","NO()") for ("entersub", "rv2cv");
533 $priv{"gv"}{32} = "EARLYCV";
534 $priv{"aelem"}{16} = $priv{"helem"}{16} = "LVDEFER";
535 $priv{$_}{16} = "OURINTR" for ("gvsv", "rv2sv", "rv2av", "rv2hv", "r2gv",
537 $priv{$_}{16} = "TARGMY"
538 for (map(($_,"s$_"),"chop", "chomp"),
539 map(($_,"i_$_"), "postinc", "postdec", "multiply", "divide", "modulo",
540 "add", "subtract", "negate"), "pow", "concat", "stringify",
541 "left_shift", "right_shift", "bit_and", "bit_xor", "bit_or",
542 "complement", "atan2", "sin", "cos", "rand", "exp", "log", "sqrt",
543 "int", "hex", "oct", "abs", "length", "index", "rindex", "sprintf",
544 "ord", "chr", "crypt", "quotemeta", "join", "push", "unshift", "flock",
545 "chdir", "chown", "chroot", "unlink", "chmod", "utime", "rename",
546 "link", "symlink", "mkdir", "rmdir", "wait", "waitpid", "system",
547 "exec", "kill", "getppid", "getpgrp", "setpgrp", "getpriority",
548 "setpriority", "time", "sleep");
549 @{$priv{"const"}}{8,16,32,64,128} = ("STRICT","ENTERED", '$[', "BARE", "WARN");
550 $priv{"flip"}{64} = $priv{"flop"}{64} = "LINENUM";
551 $priv{"list"}{64} = "GUESSED";
552 $priv{"delete"}{64} = "SLICE";
553 $priv{"exists"}{64} = "SUB";
554 $priv{$_}{64} = "LOCALE"
555 for ("sort", "prtf", "sprintf", "slt", "sle", "seq", "sne", "sgt", "sge",
556 "scmp", "lc", "uc", "lcfirst", "ucfirst");
557 @{$priv{"sort"}}{1,2,4,8,16} = ("NUM", "INT", "REV", "INPLACE","DESC");
558 $priv{"threadsv"}{64} = "SVREFd";
559 @{$priv{$_}}{16,32,64,128} = ("INBIN","INCR","OUTBIN","OUTCR")
560 for ("open", "backtick");
561 $priv{"exit"}{128} = "VMS";
562 $priv{$_}{2} = "FTACCESS"
563 for ("ftrread", "ftrwrite", "ftrexec", "fteread", "ftewrite", "fteexec");
565 # Stacked filetests are post 5.8.x
566 $priv{$_}{4} = "FTSTACKED"
567 for ("ftrread", "ftrwrite", "ftrexec", "fteread", "ftewrite", "fteexec",
568 "ftis", "fteowned", "ftrowned", "ftzero", "ftsize", "ftmtime",
569 "ftatime", "ftctime", "ftsock", "ftchr", "ftblk", "ftfile", "ftdir",
570 "ftpipe", "ftlink", "ftsuid", "ftsgid", "ftsvtx", "fttty", "fttext",
572 # Lexical $_ is post 5.8.x
573 $priv{$_}{2} = "GREPLEX"
574 for ("mapwhile", "mapstart", "grepwhile", "grepstart");
580 for my $flag (128, 96, 64, 32, 16, 8, 4, 2, 1) {
581 if ($priv{$name}{$flag} and $x & $flag and $x >= $flag) {
583 push @s, $priv{$name}{$flag};
587 return join(",", @s);
592 $hr->{svclass} = class($sv);
593 $hr->{svclass} = "UV"
594 if $hr->{svclass} eq "IV" and $sv->FLAGS & SVf_IVisUV;
595 $hr->{svaddr} = sprintf("%#x", $$sv);
596 if ($hr->{svclass} eq "GV") {
598 my $stash = $gv->STASH->NAME;
599 if ($stash eq "main") {
602 $stash = $stash . "::";
604 $hr->{svval} = "*$stash" . $gv->SAFENAME;
605 return "*$stash" . $gv->SAFENAME;
607 while (class($sv) eq "RV") {
608 $hr->{svval} .= "\\";
611 if (class($sv) eq "SPECIAL") {
612 $hr->{svval} .= ["Null", "sv_undef", "sv_yes", "sv_no"]->[$$sv];
613 } elsif ($sv->FLAGS & SVf_NOK) {
614 $hr->{svval} .= $sv->NV;
615 } elsif ($sv->FLAGS & SVf_IOK) {
616 $hr->{svval} .= $sv->int_value;
617 } elsif ($sv->FLAGS & SVf_POK) {
618 $hr->{svval} .= cstring($sv->PV);
619 } elsif (class($sv) eq "HV") {
620 $hr->{svval} .= 'HASH';
623 $hr->{svval} = 'undef' unless defined $hr->{svval};
624 my $out = $hr->{svclass};
625 return $out .= " $hr->{svval}" ;
630 my ($op, $level, $format) = @_;
632 $h{exname} = $h{name} = $op->name;
633 $h{NAME} = uc $h{name};
634 $h{class} = class($op);
635 $h{extarg} = $h{targ} = $op->targ;
636 $h{extarg} = "" unless $h{extarg};
637 if ($h{name} eq "null" and $h{targ}) {
638 # targ holds the old type
639 $h{exname} = "ex-" . substr(ppname($h{targ}), 3);
641 } elsif ($op->name =~ /^leave(sub(lv)?|write)?$/) {
642 # targ potentially holds a reference count
643 if ($op->private & 64) {
644 my $refs = "ref" . ($h{targ} != 1 ? "s" : "");
645 $h{targarglife} = $h{targarg} = "$h{targ} $refs";
648 my $padname = (($curcv->PADLIST->ARRAY)[0]->ARRAY)[$h{targ}];
649 if (defined $padname and class($padname) ne "SPECIAL") {
650 $h{targarg} = $padname->PVX;
651 if ($padname->FLAGS & SVf_FAKE) {
653 $h{targarglife} = "$h{targarg}:FAKE";
655 # These changes relate to the jumbo closure fix.
656 # See changes 19939 and 20005
658 $fake .= 'a' if $padname->IVX & 1; # PAD_FAKELEX_ANON
659 $fake .= 'm' if $padname->IVX & 2; # PAD_FAKELEX_MULTI
660 $fake .= ':' . $padname->NVX if $curcv->CvFLAGS & CVf_ANON;
661 $h{targarglife} = "$h{targarg}:FAKE:$fake";
665 my $intro = $padname->NVX - $cop_seq_base;
666 my $finish = int($padname->IVX) - $cop_seq_base;
667 $finish = "end" if $finish == 999999999 - $cop_seq_base;
668 $h{targarglife} = "$h{targarg}:$intro,$finish";
671 $h{targarglife} = $h{targarg} = "t" . $h{targ};
675 $h{svclass} = $h{svaddr} = $h{svval} = "";
676 if ($h{class} eq "PMOP") {
677 my $precomp = $op->precomp;
678 if (defined $precomp) {
679 $precomp = cstring($precomp); # Escape literal control sequences
680 $precomp = "/$precomp/";
684 my $pmreplroot = $op->pmreplroot;
686 if (ref($pmreplroot) eq "B::GV") {
687 # with C<@stash_array = split(/pat/, str);>,
688 # *stash_array is stored in /pat/'s pmreplroot.
689 $h{arg} = "($precomp => \@" . $pmreplroot->NAME . ")";
690 } elsif (!ref($pmreplroot) and $pmreplroot) {
691 # same as the last case, except the value is actually a
692 # pad offset for where the GV is kept (this happens under
694 my $gv = (($curcv->PADLIST->ARRAY)[1]->ARRAY)[$pmreplroot];
695 $h{arg} = "($precomp => \@" . $gv->NAME . ")";
696 } elsif ($ {$op->pmreplstart}) {
698 $pmreplstart = "replstart->" . seq($op->pmreplstart);
699 $h{arg} = "(" . join(" ", $precomp, $pmreplstart) . ")";
701 $h{arg} = "($precomp)";
703 } elsif ($h{class} eq "PVOP" and $h{name} ne "trans") {
704 $h{arg} = '("' . $op->pv . '")';
705 $h{svval} = '"' . $op->pv . '"';
706 } elsif ($h{class} eq "COP") {
707 my $label = $op->label;
708 $h{coplabel} = $label;
709 $label = $label ? "$label: " : "";
712 $loc .= ":" . $op->line;
713 my($stash, $cseq) = ($op->stash->NAME, $op->cop_seq - $cop_seq_base);
714 my $arybase = $op->arybase;
715 $arybase = $arybase ? ' $[=' . $arybase : "";
716 $h{arg} = "($label$stash $cseq $loc$arybase)";
717 } elsif ($h{class} eq "LOOP") {
718 $h{arg} = "(next->" . seq($op->nextop) . " last->" . seq($op->lastop)
719 . " redo->" . seq($op->redoop) . ")";
720 } elsif ($h{class} eq "LOGOP") {
722 $h{arg} = "(other->" . seq($op->other) . ")";
723 } elsif ($h{class} eq "SVOP") {
724 unless ($h{name} eq 'aelemfast' and $op->flags & OPf_SPECIAL) {
726 my $sv = (($curcv->PADLIST->ARRAY)[1]->ARRAY)[$op->targ];
727 $h{arg} = "[" . concise_sv($sv, \%h) . "]";
728 $h{targarglife} = $h{targarg} = "";
730 $h{arg} = "(" . concise_sv($op->sv, \%h) . ")";
733 } elsif ($h{class} eq "PADOP") {
734 my $sv = (($curcv->PADLIST->ARRAY)[1]->ARRAY)[$op->padix];
735 $h{arg} = "[" . concise_sv($sv, \%h) . "]";
737 $h{seq} = $h{hyphseq} = seq($op);
738 $h{seq} = "" if $h{seq} eq "-";
740 $h{static} = $op->static;
741 $h{next} = $op->next;
742 $h{next} = (class($h{next}) eq "NULL") ? "(end)" : seq($h{next});
743 $h{nextaddr} = sprintf("%#x", $ {$op->next});
744 $h{sibaddr} = sprintf("%#x", $ {$op->sibling});
745 $h{firstaddr} = sprintf("%#x", $ {$op->first}) if $op->can("first");
746 $h{lastaddr} = sprintf("%#x", $ {$op->last}) if $op->can("last");
748 $h{classsym} = $opclass{$h{class}};
749 $h{flagval} = $op->flags;
750 $h{flags} = op_flags($op->flags);
751 $h{privval} = $op->private;
752 $h{private} = private_flags($h{name}, $op->private);
753 $h{addr} = sprintf("%#x", $$op);
754 $h{label} = $labels{$$op};
755 $h{typenum} = $op->type;
756 $h{noise} = $linenoise[$op->type];
758 return fmt_line(\%h, $op, $format, $level);
762 my($op, $level) = @_;
763 if ($order eq "exec" and $lastnext and $$lastnext != $$op) {
764 # insert a 'goto' line
765 my $synth = {"seq" => seq($lastnext), "class" => class($lastnext),
766 "addr" => sprintf("%#x", $$lastnext),
767 "goto" => seq($lastnext), # simplify goto '-' removal
769 print $walkHandle fmt_line($synth, $op, $gotofmt, $level+1);
771 $lastnext = $op->next;
772 print $walkHandle concise_op($op, $level, $format);
775 # B::OP::terse (see Terse.pm) now just calls this
777 my($op, $level) = @_;
779 # This isn't necessarily right, but there's no easy way to get
780 # from an OP to the right CV. This is a limitation of the
781 # ->terse() interface style, and there isn't much to do about
782 # it. In particular, we can die in concise_op if the main pad
783 # isn't long enough, or has the wrong kind of entries, compared to
784 # the pad a sub was compiled with. The fix for that would be to
785 # make a backwards compatible "terse" format that never even
786 # looked at the pad, just like the old B::Terse. I don't think
787 # that's worth the effort, though.
788 $curcv = main_cv unless $curcv;
790 if ($order eq "exec" and $lastnext and $$lastnext != $$op) {
792 my $h = {"seq" => seq($lastnext), "class" => class($lastnext),
793 "addr" => sprintf("%#x", $$lastnext)};
795 fmt_line($h, $op, $style{"terse"}[1], $level+1);
797 $lastnext = $op->next;
799 concise_op($op, $level, $style{"terse"}[0]);
805 my $style = $tree_decorations[$tree_style];
806 my($space, $single, $kids, $kid, $nokid, $last, $lead, $size) = @$style;
807 my $name = concise_op($op, $level, $treefmt);
808 if (not $op->flags & OPf_KIDS) {
812 for (my $kid = $op->first; $$kid; $kid = $kid->sibling) {
813 push @lines, tree($kid, $level+1);
816 for ($i = $#lines; substr($lines[$i], 0, 1) eq " "; $i--) {
817 $lines[$i] = $space . $lines[$i];
820 $lines[$i] = $last . $lines[$i];
822 if (substr($lines[$i], 0, 1) eq " ") {
823 $lines[$i] = $nokid . $lines[$i];
825 $lines[$i] = $kid . $lines[$i];
828 $lines[$i] = $kids . $lines[$i];
830 $lines[0] = $single . $lines[0];
832 return("$name$lead" . shift @lines,
833 map(" " x (length($name)+$size) . $_, @lines));
836 # *** Warning: fragile kludge ahead ***
837 # Because the B::* modules run in the same interpreter as the code
838 # they're compiling, their presence tends to distort the view we have of
839 # the code we're looking at. In particular, perl gives sequence numbers
840 # to COPs. If the program we're looking at were run on its own, this
841 # would start at 1. Because all of B::Concise and all the modules it
842 # uses are compiled first, though, by the time we get to the user's
843 # program the sequence number is already pretty high, which could be
844 # distracting if you're trying to tell OPs apart. Therefore we'd like to
845 # subtract an offset from all the sequence numbers we display, to
846 # restore the simpler view of the world. The trick is to know what that
847 # offset will be, when we're still compiling B::Concise! If we
848 # hardcoded a value, it would have to change every time B::Concise or
849 # other modules we use do. To help a little, what we do here is compile
850 # a little code at the end of the module, and compute the base sequence
851 # number for the user's program as being a small offset later, so all we
852 # have to worry about are changes in the offset.
854 # When you say "perl -MO=Concise -e '$a'", the output should look like:
856 # 4 <@> leave[t1] vKP/REFC ->(end)
858 #^ smallest OP sequence number should be 1
859 # 2 <;> nextstate(main 1 -e:1) v ->3
860 # ^ smallest COP sequence number should be 1
861 # - <1> ex-rv2sv vK/1 ->4
862 # 3 <$> gvsv(*a) s ->4
864 # If the second of the marked numbers there isn't 1, it means you need
865 # to update the corresponding magic number in the next line.
866 # Remember, this needs to stay the last things in the module.
868 # Why is this different for MacOS? Does it matter?
869 my $cop_seq_mnum = $^O eq 'MacOS' ? 12 : 11;
870 $cop_seq_base = svref_2object(eval 'sub{0;}')->START->cop_seq + $cop_seq_mnum;
878 B::Concise - Walk Perl syntax tree, printing concise info about ops
882 perl -MO=Concise[,OPTIONS] foo.pl
884 use B::Concise qw(set_style add_callback);
888 This compiler backend prints the internal OPs of a Perl program's syntax
889 tree in one of several space-efficient text formats suitable for debugging
890 the inner workings of perl or other compiler backends. It can print OPs in
891 the order they appear in the OP tree, in the order they will execute, or
892 in a text approximation to their tree structure, and the format of the
893 information displyed is customizable. Its function is similar to that of
894 perl's B<-Dx> debugging flag or the B<B::Terse> module, but it is more
895 sophisticated and flexible.
899 Here's is a short example of output (aka 'rendering'), using the
900 default formatting conventions :
902 % perl -MO=Concise -e '$a = $b + 42'
903 8 <@> leave[1 ref] vKP/REFC ->(end)
905 2 <;> nextstate(main 1 -e:1) v ->3
906 7 <2> sassign vKS/2 ->8
907 5 <2> add[t1] sK/2 ->6
908 - <1> ex-rv2sv sK/1 ->4
910 4 <$> const(IV 42) s ->5
911 - <1> ex-rv2sv sKRM*/1 ->7
914 Each line corresponds to an opcode. Null ops appear as C<ex-opname>,
915 where I<opname> is the op that has been optimized away by perl.
917 The number on the first row indicates the op's sequence number. It's
918 given in base 36 by default.
920 The symbol between angle brackets indicates the op's type : for example,
921 <2> is a BINOP, <@> a LISTOP, etc. (see L</"OP class abbreviations">).
923 The opname may be followed by op-specific information in parentheses
924 (e.g. C<gvsv(*b)>), and by targ information in brackets (e.g.
927 Next come the op flags. The common flags are listed below
928 (L</"OP flags abbreviations">). The private flags follow, separated
929 by a slash. For example, C<vKP/REFC> means that the leave op has
930 public flags OPf_WANT_VOID, OPf_KIDS, and OPf_PARENS, and the private
933 Finally an arrow points to the sequence number of the next op.
937 Arguments that don't start with a hyphen are taken to be the names of
938 subroutines to print the OPs of; if no such functions are specified,
939 the main body of the program (outside any subroutines, and not
940 including use'd or require'd files) is printed. Passing C<BEGIN>,
941 C<CHECK>, C<INIT>, or C<END> will cause all of the corresponding
942 special blocks to be printed.
944 Options affect how things are rendered (ie printed). They're presented
945 here by their visual effect, 1st being strongest. They're grouped
946 according to how they interrelate; within each group the options are
947 mutually exclusive (unless otherwise stated).
949 =head2 Options for Opcode Ordering
951 These options control the 'vertical display' of opcodes. The display
952 'order' is also called 'mode' elsewhere in this document.
958 Print OPs in the order they appear in the OP tree (a preorder
959 traversal, starting at the root). The indentation of each OP shows its
960 level in the tree. This mode is the default, so the flag is included
961 simply for completeness.
965 Print OPs in the order they would normally execute (for the majority
966 of constructs this is a postorder traversal of the tree, ending at the
967 root). In most cases the OP that usually follows a given OP will
968 appear directly below it; alternate paths are shown by indentation. In
969 cases like loops when control jumps out of a linear path, a 'goto'
974 Print OPs in a text approximation of a tree, with the root of the tree
975 at the left and 'left-to-right' order of children transformed into
976 'top-to-bottom'. Because this mode grows both to the right and down,
977 it isn't suitable for large programs (unless you have a very wide
982 =head2 Options for Line-Style
984 These options select the line-style (or just style) used to render
985 each opcode, and dictates what info is actually printed into each line.
991 Use the author's favorite set of formatting conventions. This is the
996 Use formatting conventions that emulate the output of B<B::Terse>. The
997 basic mode is almost indistinguishable from the real B<B::Terse>, and the
998 exec mode looks very similar, but is in a more logical order and lacks
999 curly brackets. B<B::Terse> doesn't have a tree mode, so the tree mode
1000 is only vaguely reminiscent of B<B::Terse>.
1004 Use formatting conventions in which the name of each OP, rather than being
1005 written out in full, is represented by a one- or two-character abbreviation.
1006 This is mainly a joke.
1010 Use formatting conventions reminiscent of B<B::Debug>; these aren't
1011 very concise at all.
1015 Use formatting conventions read from the environment variables
1016 C<B_CONCISE_FORMAT>, C<B_CONCISE_GOTO_FORMAT>, and C<B_CONCISE_TREE_FORMAT>.
1020 =head2 Options for tree-specific formatting
1026 Use a tree format in which the minimum amount of space is used for the
1027 lines connecting nodes (one character in most cases). This squeezes out
1028 a few precious columns of screen real estate.
1032 Use a tree format that uses longer edges to separate OP nodes. This format
1033 tends to look better than the compact one, especially in ASCII, and is
1038 Use tree connecting characters drawn from the VT100 line-drawing set.
1039 This looks better if your terminal supports it.
1043 Draw the tree with standard ASCII characters like C<+> and C<|>. These don't
1044 look as clean as the VT100 characters, but they'll work with almost any
1045 terminal (or the horizontal scrolling mode of less(1)) and are suitable
1046 for text documentation or email. This is the default.
1050 These are pairwise exclusive, i.e. compact or loose, vt or ascii.
1052 =head2 Options controlling sequence numbering
1058 Print OP sequence numbers in base I<n>. If I<n> is greater than 10, the
1059 digit for 11 will be 'a', and so on. If I<n> is greater than 36, the digit
1060 for 37 will be 'A', and so on until 62. Values greater than 62 are not
1061 currently supported. The default is 36.
1065 Print sequence numbers with the most significant digit first. This is the
1066 usual convention for Arabic numerals, and the default.
1068 =item B<-littleendian>
1070 Print seqence numbers with the least significant digit first. This is
1071 obviously mutually exclusive with bigendian.
1075 =head2 Other options
1077 These are pairwise exclusive.
1083 Include the main program in the output, even if subroutines were also
1084 specified. This rendering is normally suppressed when a subroutine
1085 name or reference is given.
1089 This restores the default behavior after you've changed it with '-main'
1090 (it's not normally needed). If no subroutine name/ref is given, main is
1091 rendered, regardless of this flag.
1095 Renderings usually include a banner line identifying the function name
1096 or stringified subref. This suppresses the printing of the banner.
1098 TBC: Remove the stringified coderef; while it provides a 'cookie' for
1099 each function rendered, the cookies used should be 1,2,3.. not a
1100 random hex-address. It also complicates string comparison of two
1105 restores default banner behavior.
1107 =item B<-banneris> => subref
1109 TBC: a hookpoint (and an option to set it) for a user-supplied
1110 function to produce a banner appropriate for users needs. It's not
1111 ideal, because the rendering-state variables, which are a natural
1112 candidate for use in concise.t, are unavailable to the user.
1116 =head2 Option Stickiness
1118 If you invoke Concise more than once in a program, you should know that
1119 the options are 'sticky'. This means that the options you provide in
1120 the first call will be remembered for the 2nd call, unless you
1121 re-specify or change them.
1123 =head1 ABBREVIATIONS
1125 The concise style uses symbols to convey maximum info with minimal
1126 clutter (like hex addresses). With just a little practice, you can
1127 start to see the flowers, not just the branches, in the trees.
1129 =head2 OP class abbreviations
1131 These symbols appear before the op-name, and indicate the
1132 B:: namespace that represents the ops in your Perl code.
1134 0 OP (aka BASEOP) An OP with no children
1135 1 UNOP An OP with one child
1136 2 BINOP An OP with two children
1137 | LOGOP A control branch OP
1138 @ LISTOP An OP that could have lots of children
1139 / PMOP An OP with a regular expression
1140 $ SVOP An OP with an SV
1141 " PVOP An OP with a string
1142 { LOOP An OP that holds pointers for a loop
1143 ; COP An OP that marks the start of a statement
1144 # PADOP An OP with a GV on the pad
1146 =head2 OP flags abbreviations
1148 These symbols represent various flags which alter behavior of the
1149 opcode, sometimes in opcode-specific ways.
1151 v OPf_WANT_VOID Want nothing (void context)
1152 s OPf_WANT_SCALAR Want single value (scalar context)
1153 l OPf_WANT_LIST Want list of any length (list context)
1154 K OPf_KIDS There is a firstborn child.
1155 P OPf_PARENS This operator was parenthesized.
1156 (Or block needs explicit scope entry.)
1157 R OPf_REF Certified reference.
1158 (Return container, not containee).
1159 M OPf_MOD Will modify (lvalue).
1160 S OPf_STACKED Some arg is arriving on the stack.
1161 * OPf_SPECIAL Do something weird for this op (see op.h)
1163 =head1 FORMATTING SPECIFICATIONS
1165 For each line-style ('concise', 'terse', 'linenoise', etc.) there are
1166 3 format-specs which control how OPs are rendered.
1168 The first is the 'default' format, which is used in both basic and exec
1169 modes to print all opcodes. The 2nd, goto-format, is used in exec
1170 mode when branches are encountered. They're not real opcodes, and are
1171 inserted to look like a closing curly brace. The tree-format is tree
1174 When a line is rendered, the correct format-spec is copied and scanned
1175 for the following items; data is substituted in, and other
1176 manipulations like basic indenting are done, for each opcode rendered.
1178 There are 3 kinds of items that may be populated; special patterns,
1179 #vars, and literal text, which is copied verbatim. (Yes, it's a set
1182 =head2 Special Patterns
1184 These items are the primitives used to perform indenting, and to
1185 select text from amongst alternatives.
1189 =item B<(x(>I<exec_text>B<;>I<basic_text>B<)x)>
1191 Generates I<exec_text> in exec mode, or I<basic_text> in basic mode.
1193 =item B<(*(>I<text>B<)*)>
1195 Generates one copy of I<text> for each indentation level.
1197 =item B<(*(>I<text1>B<;>I<text2>B<)*)>
1199 Generates one fewer copies of I<text1> than the indentation level, followed
1200 by one copy of I<text2> if the indentation level is more than 0.
1202 =item B<(?(>I<text1>B<#>I<var>I<Text2>B<)?)>
1204 If the value of I<var> is true (not empty or zero), generates the
1205 value of I<var> surrounded by I<text1> and I<Text2>, otherwise
1210 Any number of tildes and surrounding whitespace will be collapsed to
1217 These #vars represent opcode properties that you may want as part of
1218 your rendering. The '#' is intended as a private sigil; a #var's
1219 value is interpolated into the style-line, much like "read $this".
1221 These vars take 3 forms:
1227 A property named 'var' is assumed to exist for the opcodes, and is
1228 interpolated into the rendering.
1230 =item B<#>I<var>I<N>
1232 Generates the value of I<var>, left justified to fill I<N> spaces.
1233 Note that this means while you can have properties 'foo' and 'foo2',
1234 you cannot render 'foo2', but you could with 'foo2a'. You would be
1235 wise not to rely on this behavior going forward ;-)
1239 This ucfirst form of #var generates a tag-value form of itself for
1240 display; it converts '#Var' into a 'Var => #var' style, which is then
1241 handled as described above. (Imp-note: #Vars cannot be used for
1242 conditional-fills, because the => #var transform is done after the check
1247 The following variables are 'defined' by B::Concise; when they are
1248 used in a style, their respective values are plugged into the
1249 rendering of each opcode.
1251 Only some of these are used by the standard styles, the others are
1252 provided for you to delve into optree mechanics, should you wish to
1253 add a new style (see L</add_style> below) that uses them. You can
1254 also add new ones using L<add_callback>.
1260 The address of the OP, in hexadecimal.
1264 The OP-specific information of the OP (such as the SV for an SVOP, the
1265 non-local exit pointers for a LOOP, etc.) enclosed in parentheses.
1269 The B-determined class of the OP, in all caps.
1273 A single symbol abbreviating the class of the OP.
1277 The label of the statement or block the OP is the start of, if any.
1281 The name of the OP, or 'ex-foo' if the OP is a null that used to be a foo.
1285 The target of the OP, or nothing for a nulled OP.
1289 The address of the OP's first child, in hexidecimal.
1293 The OP's flags, abbreviated as a series of symbols.
1297 The numeric value of the OP's flags.
1301 The sequence number of the OP, or a hyphen if it doesn't have one.
1305 'NEXT', 'LAST', or 'REDO' if the OP is a target of one of those in exec
1306 mode, or empty otherwise.
1310 The address of the OP's last child, in hexidecimal.
1318 The OP's name, in all caps.
1322 The sequence number of the OP's next OP.
1326 The address of the OP's next OP, in hexidecimal.
1330 A one- or two-character abbreviation for the OP's name.
1334 The OP's private flags, rendered with abbreviated names if possible.
1338 The numeric value of the OP's private flags.
1342 The sequence number of the OP. Note that this is a sequence number
1343 generated by B::Concise.
1347 Whether or not the op has been optimised by the peephole optimiser.
1351 Whether or not the op is statically defined. This flag is used by the
1352 B::C compiler backend and indicates that the op should not be freed.
1356 The address of the OP's next youngest sibling, in hexidecimal.
1360 The address of the OP's SV, if it has an SV, in hexidecimal.
1364 The class of the OP's SV, if it has one, in all caps (e.g., 'IV').
1368 The value of the OP's SV, if it has one, in a short human-readable format.
1372 The numeric value of the OP's targ.
1376 The name of the variable the OP's targ refers to, if any, otherwise the
1377 letter t followed by the OP's targ in decimal.
1379 =item B<#targarglife>
1381 Same as B<#targarg>, but followed by the COP sequence numbers that delimit
1382 the variable's lifetime (or 'end' for a variable in an open scope) for a
1387 The numeric value of the OP's type, in decimal.
1391 =head1 Using B::Concise outside of the O framework
1393 The common (and original) usage of B::Concise was for command-line
1394 renderings of simple code, as given in EXAMPLE. But you can also use
1395 B<B::Concise> from your code, and call compile() directly, and
1396 repeatedly. By doing so, you can avoid the compile-time only
1397 operation of O.pm, and even use the debugger to step through
1398 B::Concise::compile() itself.
1400 Once you're doing this, you may alter Concise output by adding new
1401 rendering styles, and by optionally adding callback routines which
1402 populate new variables, if such were referenced from those (just
1405 =head2 Example: Altering Concise Renderings
1407 use B::Concise qw(set_style add_callback);
1408 add_style($yourStyleName => $defaultfmt, $gotofmt, $treefmt);
1411 my ($h, $op, $format, $level, $stylename) = @_;
1412 $h->{variable} = some_func($op);
1414 $walker = B::Concise::compile(@options,@subnames,@subrefs);
1419 B<set_style> accepts 3 arguments, and updates the three format-specs
1420 comprising a line-style (basic-exec, goto, tree). It has one minor
1421 drawback though; it doesn't register the style under a new name. This
1422 can become an issue if you render more than once and switch styles.
1423 Thus you may prefer to use add_style() and/or set_style_standard()
1426 =head2 set_style_standard($name)
1428 This restores one of the standard line-styles: C<terse>, C<concise>,
1429 C<linenoise>, C<debug>, C<env>, into effect. It also accepts style
1430 names previously defined with add_style().
1434 This subroutine accepts a new style name and three style arguments as
1435 above, and creates, registers, and selects the newly named style. It is
1436 an error to re-add a style; call set_style_standard() to switch between
1439 =head2 add_callback()
1441 If your newly minted styles refer to any #variables, you'll need to
1442 define a callback subroutine that will populate (or modify) those
1443 variables. They are then available for use in the style you've chosen.
1445 The callbacks are called for each opcode visited by Concise, in the
1446 same order as they are added. Each subroutine is passed five
1449 1. A hashref, containing the variable names and values which are
1450 populated into the report-line for the op
1451 2. the op, as a B<B::OP> object
1452 3. a reference to the format string
1453 4. the formatting (indent) level
1454 5. the selected stylename
1456 To define your own variables, simply add them to the hash, or change
1457 existing values if you need to. The level and format are passed in as
1458 references to scalars, but it is unlikely that they will need to be
1459 changed or even used.
1461 =head2 Running B::Concise::compile()
1463 B<compile> accepts options as described above in L</OPTIONS>, and
1464 arguments, which are either coderefs, or subroutine names.
1466 It constructs and returns a $treewalker coderef, which when invoked,
1467 traverses, or walks, and renders the optrees of the given arguments to
1468 STDOUT. You can reuse this, and can change the rendering style used
1469 each time; thereafter the coderef renders in the new style.
1471 B<walk_output> lets you change the print destination from STDOUT to
1472 another open filehandle, or (unless you've built with -Uuseperlio)
1473 into a string passed as a ref.
1475 my $walker = B::Concise::compile('-terse','aFuncName', \&aSubRef); # 1
1476 walk_output(\my $buf);
1477 $walker->(); # 1 renders -terse
1478 set_style_standard('concise'); # 2
1479 $walker->(); # 2 renders -concise
1480 $walker->(@new); # 3 renders whatever
1481 print "3 different renderings: terse, concise, and @new: $buf\n";
1483 When $walker is called, it traverses the subroutines supplied when it
1484 was created, and renders them using the current style. You can change
1485 the style afterwards in several different ways:
1487 1. call C<compile>, altering style or mode/order
1488 2. call C<set_style_standard>
1489 3. call $walker, passing @new options
1491 Passing new options to the $walker is the easiest way to change
1492 amongst any pre-defined styles (the ones you add are automatically
1493 recognized as options), and is the only way to alter rendering order
1494 without calling compile again. Note however that rendering state is
1495 still shared amongst multiple $walker objects, so they must still be
1496 used in a coordinated manner.
1498 =head2 B::Concise::reset_sequence()
1500 This function (not exported) lets you reset the sequence numbers (note
1501 that they're numbered arbitrarily, their goal being to be human
1502 readable). Its purpose is mostly to support testing, i.e. to compare
1503 the concise output from two identical anonymous subroutines (but
1504 different instances). Without the reset, B::Concise, seeing that
1505 they're separate optrees, generates different sequence numbers in
1510 All detected errors, (invalid arguments, internal errors, etc.) are
1511 resolved with a die($message). Use an eval if you wish to catch these
1512 errors and continue processing.
1514 In particular, B<compile> will die if you've asked for a non-existent
1515 function-name, a non-existent coderef, or a non-CODE reference.
1519 Stephen McCamant, E<lt>smcc@CSUA.Berkeley.EDUE<gt>.