source: for-distributions/trunk/bin/windows/perl/lib/Data/Dumper.pm@ 14489

Last change on this file since 14489 was 14489, checked in by oranfry, 17 years ago

upgrading to perl 5.8
File size: 37.2 KB
Line 
1#
2# Data/Dumper.pm
3#
4# convert perl data structures into perl syntax suitable for both printing
5# and eval
6#
7# Documentation at the __END__
8#
9
10package Data::Dumper;
11
12$VERSION = '2.121_08';
13
14#$| = 1;
15
16use 5.006_001;
17require Exporter;
18require overload;
19
20use Carp;
21
22BEGIN {
23 @ISA = qw(Exporter);
24 @EXPORT = qw(Dumper);
25 @EXPORT_OK = qw(DumperX);
26
27 # if run under miniperl, or otherwise lacking dynamic loading,
28 # XSLoader should be attempted to load, or the pure perl flag
29 # toggled on load failure.
30 eval {
31 require XSLoader;
32 };
33 $Useperl = 1 if $@;
34}
35
36XSLoader::load( 'Data::Dumper' ) unless $Useperl;
37
38# module vars and their defaults
39$Indent = 2 unless defined $Indent;
40$Purity = 0 unless defined $Purity;
41$Pad = "" unless defined $Pad;
42$Varname = "VAR" unless defined $Varname;
43$Useqq = 0 unless defined $Useqq;
44$Terse = 0 unless defined $Terse;
45$Freezer = "" unless defined $Freezer;
46$Toaster = "" unless defined $Toaster;
47$Deepcopy = 0 unless defined $Deepcopy;
48$Quotekeys = 1 unless defined $Quotekeys;
49$Bless = "bless" unless defined $Bless;
50#$Expdepth = 0 unless defined $Expdepth;
51$Maxdepth = 0 unless defined $Maxdepth;
52$Pair = ' => ' unless defined $Pair;
53$Useperl = 0 unless defined $Useperl;
54$Sortkeys = 0 unless defined $Sortkeys;
55$Deparse = 0 unless defined $Deparse;
56
57#
58# expects an arrayref of values to be dumped.
59# can optionally pass an arrayref of names for the values.
60# names must have leading $ sign stripped. begin the name with *
61# to cause output of arrays and hashes rather than refs.
62#
63sub new {
64 my($c, $v, $n) = @_;
65
66 croak "Usage: PACKAGE->new(ARRAYREF, [ARRAYREF])"
67 unless (defined($v) && (ref($v) eq 'ARRAY'));
68 $n = [] unless (defined($n) && (ref($v) eq 'ARRAY'));
69
70 my($s) = {
71 level => 0, # current recursive depth
72 indent => $Indent, # various styles of indenting
73 pad => $Pad, # all lines prefixed by this string
74 xpad => "", # padding-per-level
75 apad => "", # added padding for hash keys n such
76 sep => "", # list separator
77 pair => $Pair, # hash key/value separator: defaults to ' => '
78 seen => {}, # local (nested) refs (id => [name, val])
79 todump => $v, # values to dump []
80 names => $n, # optional names for values []
81 varname => $Varname, # prefix to use for tagging nameless ones
82 purity => $Purity, # degree to which output is evalable
83 useqq => $Useqq, # use "" for strings (backslashitis ensues)
84 terse => $Terse, # avoid name output (where feasible)
85 freezer => $Freezer, # name of Freezer method for objects
86 toaster => $Toaster, # name of method to revive objects
87 deepcopy => $Deepcopy, # dont cross-ref, except to stop recursion
88 quotekeys => $Quotekeys, # quote hash keys
89 'bless' => $Bless, # keyword to use for "bless"
90# expdepth => $Expdepth, # cutoff depth for explicit dumping
91 maxdepth => $Maxdepth, # depth beyond which we give up
92 useperl => $Useperl, # use the pure Perl implementation
93 sortkeys => $Sortkeys, # flag or filter for sorting hash keys
94 deparse => $Deparse, # use B::Deparse for coderefs
95 };
96
97 if ($Indent > 0) {
98 $s->{xpad} = " ";
99 $s->{sep} = "\n";
100 }
101 return bless($s, $c);
102}
103
104sub init_refaddr_format {
105 require Config;
106 my $f = $Config::Config{uvxformat};
107 $f =~ tr/"//d;
108 our $refaddr_format = "0x%" . $f;
109}
110
111sub format_refaddr {
112 require Scalar::Util;
113 sprintf our $refaddr_format, Scalar::Util::refaddr(shift);
114}
115
116#
117# add-to or query the table of already seen references
118#
119sub Seen {
120 my($s, $g) = @_;
121 if (defined($g) && (ref($g) eq 'HASH')) {
122 my($k, $v, $id);
123 while (($k, $v) = each %$g) {
124 if (defined $v and ref $v) {
125 $id = format_refaddr($v);
126 if ($k =~ /^[*](.*)$/) {
127 $k = (ref $v eq 'ARRAY') ? ( "\\\@" . $1 ) :
128 (ref $v eq 'HASH') ? ( "\\\%" . $1 ) :
129 (ref $v eq 'CODE') ? ( "\\\&" . $1 ) :
130 ( "\$" . $1 ) ;
131 }
132 elsif ($k !~ /^\$/) {
133 $k = "\$" . $k;
134 }
135 $s->{seen}{$id} = [$k, $v];
136 }
137 else {
138 carp "Only refs supported, ignoring non-ref item \$$k";
139 }
140 }
141 return $s;
142 }
143 else {
144 return map { @$_ } values %{$s->{seen}};
145 }
146}
147
148#
149# set or query the values to be dumped
150#
151sub Values {
152 my($s, $v) = @_;
153 if (defined($v) && (ref($v) eq 'ARRAY')) {
154 $s->{todump} = [@$v]; # make a copy
155 return $s;
156 }
157 else {
158 return @{$s->{todump}};
159 }
160}
161
162#
163# set or query the names of the values to be dumped
164#
165sub Names {
166 my($s, $n) = @_;
167 if (defined($n) && (ref($n) eq 'ARRAY')) {
168 $s->{names} = [@$n]; # make a copy
169 return $s;
170 }
171 else {
172 return @{$s->{names}};
173 }
174}
175
176sub DESTROY {}
177
178sub Dump {
179 return &Dumpxs
180 unless $Data::Dumper::Useperl || (ref($_[0]) && $_[0]->{useperl}) ||
181 $Data::Dumper::Useqq || (ref($_[0]) && $_[0]->{useqq}) ||
182 $Data::Dumper::Deparse || (ref($_[0]) && $_[0]->{deparse});
183 return &Dumpperl;
184}
185
186#
187# dump the refs in the current dumper object.
188# expects same args as new() if called via package name.
189#
190sub Dumpperl {
191 my($s) = shift;
192 my(@out, $val, $name);
193 my($i) = 0;
194 local(@post);
195 init_refaddr_format();
196
197 $s = $s->new(@_) unless ref $s;
198
199 for $val (@{$s->{todump}}) {
200 my $out = "";
201 @post = ();
202 $name = $s->{names}[$i++];
203 if (defined $name) {
204 if ($name =~ /^[*](.*)$/) {
205 if (defined $val) {
206 $name = (ref $val eq 'ARRAY') ? ( "\@" . $1 ) :
207 (ref $val eq 'HASH') ? ( "\%" . $1 ) :
208 (ref $val eq 'CODE') ? ( "\*" . $1 ) :
209 ( "\$" . $1 ) ;
210 }
211 else {
212 $name = "\$" . $1;
213 }
214 }
215 elsif ($name !~ /^\$/) {
216 $name = "\$" . $name;
217 }
218 }
219 else {
220 $name = "\$" . $s->{varname} . $i;
221 }
222
223 my $valstr;
224 {
225 local($s->{apad}) = $s->{apad};
226 $s->{apad} .= ' ' x (length($name) + 3) if $s->{indent} >= 2;
227 $valstr = $s->_dump($val, $name);
228 }
229
230 $valstr = "$name = " . $valstr . ';' if @post or !$s->{terse};
231 $out .= $s->{pad} . $valstr . $s->{sep};
232 $out .= $s->{pad} . join(';' . $s->{sep} . $s->{pad}, @post)
233 . ';' . $s->{sep} if @post;
234
235 push @out, $out;
236 }
237 return wantarray ? @out : join('', @out);
238}
239
240#
241# twist, toil and turn;
242# and recurse, of course.
243# sometimes sordidly;
244# and curse if no recourse.
245#
246sub _dump {
247 my($s, $val, $name) = @_;
248 my($sname);
249 my($out, $realpack, $realtype, $type, $ipad, $id, $blesspad);
250
251 $type = ref $val;
252 $out = "";
253
254 if ($type) {
255
256 # Call the freezer method if it's specified and the object has the
257 # method. Trap errors and warn() instead of die()ing, like the XS
258 # implementation.
259 my $freezer = $s->{freezer};
260 if ($freezer and UNIVERSAL::can($val, $freezer)) {
261 eval { $val->$freezer() };
262 warn "WARNING(Freezer method call failed): $@" if $@;
263 }
264
265 require Scalar::Util;
266 $realpack = Scalar::Util::blessed($val);
267 $realtype = $realpack ? Scalar::Util::reftype($val) : ref $val;
268 $id = format_refaddr($val);
269
270 # if it has a name, we need to either look it up, or keep a tab
271 # on it so we know when we hit it later
272 if (defined($name) and length($name)) {
273 # keep a tab on it so that we dont fall into recursive pit
274 if (exists $s->{seen}{$id}) {
275# if ($s->{expdepth} < $s->{level}) {
276 if ($s->{purity} and $s->{level} > 0) {
277 $out = ($realtype eq 'HASH') ? '{}' :
278 ($realtype eq 'ARRAY') ? '[]' :
279 'do{my $o}' ;
280 push @post, $name . " = " . $s->{seen}{$id}[0];
281 }
282 else {
283 $out = $s->{seen}{$id}[0];
284 if ($name =~ /^([\@\%])/) {
285 my $start = $1;
286 if ($out =~ /^\\$start/) {
287 $out = substr($out, 1);
288 }
289 else {
290 $out = $start . '{' . $out . '}';
291 }
292 }
293 }
294 return $out;
295# }
296 }
297 else {
298 # store our name
299 $s->{seen}{$id} = [ (($name =~ /^[@%]/) ? ('\\' . $name ) :
300 ($realtype eq 'CODE' and
301 $name =~ /^[*](.*)$/) ? ('\\&' . $1 ) :
302 $name ),
303 $val ];
304 }
305 }
306
307 if ($realpack and $realpack eq 'Regexp') {
308 $out = "$val";
309 $out =~ s,/,\\/,g;
310 return "qr/$out/";
311 }
312
313 # If purity is not set and maxdepth is set, then check depth:
314 # if we have reached maximum depth, return the string
315 # representation of the thing we are currently examining
316 # at this depth (i.e., 'Foo=ARRAY(0xdeadbeef)').
317 if (!$s->{purity}
318 and $s->{maxdepth} > 0
319 and $s->{level} >= $s->{maxdepth})
320 {
321 return qq['$val'];
322 }
323
324 # we have a blessed ref
325 if ($realpack) {
326 $out = $s->{'bless'} . '( ';
327 $blesspad = $s->{apad};
328 $s->{apad} .= ' ' if ($s->{indent} >= 2);
329 }
330
331 $s->{level}++;
332 $ipad = $s->{xpad} x $s->{level};
333
334 if ($realtype eq 'SCALAR' || $realtype eq 'REF') {
335 if ($realpack) {
336 $out .= 'do{\\(my $o = ' . $s->_dump($$val, "\${$name}") . ')}';
337 }
338 else {
339 $out .= '\\' . $s->_dump($$val, "\${$name}");
340 }
341 }
342 elsif ($realtype eq 'GLOB') {
343 $out .= '\\' . $s->_dump($$val, "*{$name}");
344 }
345 elsif ($realtype eq 'ARRAY') {
346 my($v, $pad, $mname);
347 my($i) = 0;
348 $out .= ($name =~ /^\@/) ? '(' : '[';
349 $pad = $s->{sep} . $s->{pad} . $s->{apad};
350 ($name =~ /^\@(.*)$/) ? ($mname = "\$" . $1) :
351 # omit -> if $foo->[0]->{bar}, but not ${$foo->[0]}->{bar}
352 ($name =~ /^\\?[\%\@\*\$][^{].*[]}]$/) ? ($mname = $name) :
353 ($mname = $name . '->');
354 $mname .= '->' if $mname =~ /^\*.+\{[A-Z]+\}$/;
355 for $v (@$val) {
356 $sname = $mname . '[' . $i . ']';
357 $out .= $pad . $ipad . '#' . $i if $s->{indent} >= 3;
358 $out .= $pad . $ipad . $s->_dump($v, $sname);
359 $out .= "," if $i++ < $#$val;
360 }
361 $out .= $pad . ($s->{xpad} x ($s->{level} - 1)) if $i;
362 $out .= ($name =~ /^\@/) ? ')' : ']';
363 }
364 elsif ($realtype eq 'HASH') {
365 my($k, $v, $pad, $lpad, $mname, $pair);
366 $out .= ($name =~ /^\%/) ? '(' : '{';
367 $pad = $s->{sep} . $s->{pad} . $s->{apad};
368 $lpad = $s->{apad};
369 $pair = $s->{pair};
370 ($name =~ /^\%(.*)$/) ? ($mname = "\$" . $1) :
371 # omit -> if $foo->[0]->{bar}, but not ${$foo->[0]}->{bar}
372 ($name =~ /^\\?[\%\@\*\$][^{].*[]}]$/) ? ($mname = $name) :
373 ($mname = $name . '->');
374 $mname .= '->' if $mname =~ /^\*.+\{[A-Z]+\}$/;
375 my ($sortkeys, $keys, $key) = ("$s->{sortkeys}");
376 if ($sortkeys) {
377 if (ref($s->{sortkeys}) eq 'CODE') {
378 $keys = $s->{sortkeys}($val);
379 unless (ref($keys) eq 'ARRAY') {
380 carp "Sortkeys subroutine did not return ARRAYREF";
381 $keys = [];
382 }
383 }
384 else {
385 $keys = [ sort keys %$val ];
386 }
387 }
388 while (($k, $v) = ! $sortkeys ? (each %$val) :
389 @$keys ? ($key = shift(@$keys), $val->{$key}) :
390 () )
391 {
392 my $nk = $s->_dump($k, "");
393 $nk = $1 if !$s->{quotekeys} and $nk =~ /^[\"\']([A-Za-z_]\w*)[\"\']$/;
394 $sname = $mname . '{' . $nk . '}';
395 $out .= $pad . $ipad . $nk . $pair;
396
397 # temporarily alter apad
398 $s->{apad} .= (" " x (length($nk) + 4)) if $s->{indent} >= 2;
399 $out .= $s->_dump($val->{$k}, $sname) . ",";
400 $s->{apad} = $lpad if $s->{indent} >= 2;
401 }
402 if (substr($out, -1) eq ',') {
403 chop $out;
404 $out .= $pad . ($s->{xpad} x ($s->{level} - 1));
405 }
406 $out .= ($name =~ /^\%/) ? ')' : '}';
407 }
408 elsif ($realtype eq 'CODE') {
409 if ($s->{deparse}) {
410 require B::Deparse;
411 my $sub = 'sub ' . (B::Deparse->new)->coderef2text($val);
412 $pad = $s->{sep} . $s->{pad} . $s->{apad} . $s->{xpad} x ($s->{level} - 1);
413 $sub =~ s/\n/$pad/gse;
414 $out .= $sub;
415 } else {
416 $out .= 'sub { "DUMMY" }';
417 carp "Encountered CODE ref, using dummy placeholder" if $s->{purity};
418 }
419 }
420 else {
421 croak "Can\'t handle $realtype type.";
422 }
423
424 if ($realpack) { # we have a blessed ref
425 $out .= ', \'' . $realpack . '\'' . ' )';
426 $out .= '->' . $s->{toaster} . '()' if $s->{toaster} ne '';
427 $s->{apad} = $blesspad;
428 }
429 $s->{level}--;
430
431 }
432 else { # simple scalar
433
434 my $ref = \$_[1];
435 # first, catalog the scalar
436 if ($name ne '') {
437 $id = format_refaddr($ref);
438 if (exists $s->{seen}{$id}) {
439 if ($s->{seen}{$id}[2]) {
440 $out = $s->{seen}{$id}[0];
441 #warn "[<$out]\n";
442 return "\${$out}";
443 }
444 }
445 else {
446 #warn "[>\\$name]\n";
447 $s->{seen}{$id} = ["\\$name", $ref];
448 }
449 }
450 if (ref($ref) eq 'GLOB' or "$ref" =~ /=GLOB\([^()]+\)$/) { # glob
451 my $name = substr($val, 1);
452 if ($name =~ /^[A-Za-z_][\w:]*$/) {
453 $name =~ s/^main::/::/;
454 $sname = $name;
455 }
456 else {
457 $sname = $s->_dump($name, "");
458 $sname = '{' . $sname . '}';
459 }
460 if ($s->{purity}) {
461 my $k;
462 local ($s->{level}) = 0;
463 for $k (qw(SCALAR ARRAY HASH)) {
464 my $gval = *$val{$k};
465 next unless defined $gval;
466 next if $k eq "SCALAR" && ! defined $$gval; # always there
467
468 # _dump can push into @post, so we hold our place using $postlen
469 my $postlen = scalar @post;
470 $post[$postlen] = "\*$sname = ";
471 local ($s->{apad}) = " " x length($post[$postlen]) if $s->{indent} >= 2;
472 $post[$postlen] .= $s->_dump($gval, "\*$sname\{$k\}");
473 }
474 }
475 $out .= '*' . $sname;
476 }
477 elsif (!defined($val)) {
478 $out .= "undef";
479 }
480 elsif ($val =~ /^(?:0|-?[1-9]\d{0,8})\z/) { # safe decimal number
481 $out .= $val;
482 }
483 else { # string
484 if ($s->{useqq} or $val =~ tr/\0-\377//c) {
485 # Fall back to qq if there's unicode
486 $out .= qquote($val, $s->{useqq});
487 }
488 else {
489 $val =~ s/([\\\'])/\\$1/g;
490 $out .= '\'' . $val . '\'';
491 }
492 }
493 }
494 if ($id) {
495 # if we made it this far, $id was added to seen list at current
496 # level, so remove it to get deep copies
497 if ($s->{deepcopy}) {
498 delete($s->{seen}{$id});
499 }
500 elsif ($name) {
501 $s->{seen}{$id}[2] = 1;
502 }
503 }
504 return $out;
505}
506
507#
508# non-OO style of earlier version
509#
510sub Dumper {
511 return Data::Dumper->Dump([@_]);
512}
513
514# compat stub
515sub DumperX {
516 return Data::Dumper->Dumpxs([@_], []);
517}
518
519sub Dumpf { return Data::Dumper->Dump(@_) }
520
521sub Dumpp { print Data::Dumper->Dump(@_) }
522
523#
524# reset the "seen" cache
525#
526sub Reset {
527 my($s) = shift;
528 $s->{seen} = {};
529 return $s;
530}
531
532sub Indent {
533 my($s, $v) = @_;
534 if (defined($v)) {
535 if ($v == 0) {
536 $s->{xpad} = "";
537 $s->{sep} = "";
538 }
539 else {
540 $s->{xpad} = " ";
541 $s->{sep} = "\n";
542 }
543 $s->{indent} = $v;
544 return $s;
545 }
546 else {
547 return $s->{indent};
548 }
549}
550
551sub Pair {
552 my($s, $v) = @_;
553 defined($v) ? (($s->{pair} = $v), return $s) : $s->{pair};
554}
555
556sub Pad {
557 my($s, $v) = @_;
558 defined($v) ? (($s->{pad} = $v), return $s) : $s->{pad};
559}
560
561sub Varname {
562 my($s, $v) = @_;
563 defined($v) ? (($s->{varname} = $v), return $s) : $s->{varname};
564}
565
566sub Purity {
567 my($s, $v) = @_;
568 defined($v) ? (($s->{purity} = $v), return $s) : $s->{purity};
569}
570
571sub Useqq {
572 my($s, $v) = @_;
573 defined($v) ? (($s->{useqq} = $v), return $s) : $s->{useqq};
574}
575
576sub Terse {
577 my($s, $v) = @_;
578 defined($v) ? (($s->{terse} = $v), return $s) : $s->{terse};
579}
580
581sub Freezer {
582 my($s, $v) = @_;
583 defined($v) ? (($s->{freezer} = $v), return $s) : $s->{freezer};
584}
585
586sub Toaster {
587 my($s, $v) = @_;
588 defined($v) ? (($s->{toaster} = $v), return $s) : $s->{toaster};
589}
590
591sub Deepcopy {
592 my($s, $v) = @_;
593 defined($v) ? (($s->{deepcopy} = $v), return $s) : $s->{deepcopy};
594}
595
596sub Quotekeys {
597 my($s, $v) = @_;
598 defined($v) ? (($s->{quotekeys} = $v), return $s) : $s->{quotekeys};
599}
600
601sub Bless {
602 my($s, $v) = @_;
603 defined($v) ? (($s->{'bless'} = $v), return $s) : $s->{'bless'};
604}
605
606sub Maxdepth {
607 my($s, $v) = @_;
608 defined($v) ? (($s->{'maxdepth'} = $v), return $s) : $s->{'maxdepth'};
609}
610
611sub Useperl {
612 my($s, $v) = @_;
613 defined($v) ? (($s->{'useperl'} = $v), return $s) : $s->{'useperl'};
614}
615
616sub Sortkeys {
617 my($s, $v) = @_;
618 defined($v) ? (($s->{'sortkeys'} = $v), return $s) : $s->{'sortkeys'};
619}
620
621sub Deparse {
622 my($s, $v) = @_;
623 defined($v) ? (($s->{'deparse'} = $v), return $s) : $s->{'deparse'};
624}
625
626# used by qquote below
627my %esc = (
628 "\a" => "\\a",
629 "\b" => "\\b",
630 "\t" => "\\t",
631 "\n" => "\\n",
632 "\f" => "\\f",
633 "\r" => "\\r",
634 "\e" => "\\e",
635);
636
637# put a string value in double quotes
638sub qquote {
639 local($_) = shift;
640 s/([\\\"\@\$])/\\$1/g;
641 my $bytes; { use bytes; $bytes = length }
642 s/([^\x00-\x7f])/'\x{'.sprintf("%x",ord($1)).'}'/ge if $bytes > length;
643 return qq("$_") unless
644 /[^ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~]/; # fast exit
645
646 my $high = shift || "";
647 s/([\a\b\t\n\f\r\e])/$esc{$1}/g;
648
649 if (ord('^')==94) { # ascii
650 # no need for 3 digits in escape for these
651 s/([\0-\037])(?!\d)/'\\'.sprintf('%o',ord($1))/eg;
652 s/([\0-\037\177])/'\\'.sprintf('%03o',ord($1))/eg;
653 # all but last branch below not supported --BEHAVIOR SUBJECT TO CHANGE--
654 if ($high eq "iso8859") {
655 s/([\200-\240])/'\\'.sprintf('%o',ord($1))/eg;
656 } elsif ($high eq "utf8") {
657# use utf8;
658# $str =~ s/([^\040-\176])/sprintf "\\x{%04x}", ord($1)/ge;
659 } elsif ($high eq "8bit") {
660 # leave it as it is
661 } else {
662 s/([\200-\377])/'\\'.sprintf('%03o',ord($1))/eg;
663 s/([^\040-\176])/sprintf "\\x{%04x}", ord($1)/ge;
664 }
665 }
666 else { # ebcdic
667 s{([^ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~])(?!\d)}
668 {my $v = ord($1); '\\'.sprintf(($v <= 037 ? '%o' : '%03o'), $v)}eg;
669 s{([^ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~])}
670 {'\\'.sprintf('%03o',ord($1))}eg;
671 }
672
673 return qq("$_");
674}
675
676# helper sub to sort hash keys in Perl < 5.8.0 where we don't have
677# access to sortsv() from XS
678sub _sortkeys { [ sort keys %{$_[0]} ] }
679
6801;
681__END__
682
683=head1 NAME
684
685Data::Dumper - stringified perl data structures, suitable for both printing and C<eval>
686
687=head1 SYNOPSIS
688
689 use Data::Dumper;
690
691 # simple procedural interface
692 print Dumper($foo, $bar);
693
694 # extended usage with names
695 print Data::Dumper->Dump([$foo, $bar], [qw(foo *ary)]);
696
697 # configuration variables
698 {
699 local $Data::Dumper::Purity = 1;
700 eval Data::Dumper->Dump([$foo, $bar], [qw(foo *ary)]);
701 }
702
703 # OO usage
704 $d = Data::Dumper->new([$foo, $bar], [qw(foo *ary)]);
705 ...
706 print $d->Dump;
707 ...
708 $d->Purity(1)->Terse(1)->Deepcopy(1);
709 eval $d->Dump;
710
711
712=head1 DESCRIPTION
713
714Given a list of scalars or reference variables, writes out their contents in
715perl syntax. The references can also be objects. The contents of each
716variable is output in a single Perl statement. Handles self-referential
717structures correctly.
718
719The return value can be C<eval>ed to get back an identical copy of the
720original reference structure.
721
722Any references that are the same as one of those passed in will be named
723C<$VAR>I<n> (where I<n> is a numeric suffix), and other duplicate references
724to substructures within C<$VAR>I<n> will be appropriately labeled using arrow
725notation. You can specify names for individual values to be dumped if you
726use the C<Dump()> method, or you can change the default C<$VAR> prefix to
727something else. See C<$Data::Dumper::Varname> and C<$Data::Dumper::Terse>
728below.
729
730The default output of self-referential structures can be C<eval>ed, but the
731nested references to C<$VAR>I<n> will be undefined, since a recursive
732structure cannot be constructed using one Perl statement. You should set the
733C<Purity> flag to 1 to get additional statements that will correctly fill in
734these references. Moreover, if C<eval>ed when strictures are in effect,
735you need to ensure that any variables it accesses are previously declared.
736
737In the extended usage form, the references to be dumped can be given
738user-specified names. If a name begins with a C<*>, the output will
739describe the dereferenced type of the supplied reference for hashes and
740arrays, and coderefs. Output of names will be avoided where possible if
741the C<Terse> flag is set.
742
743In many cases, methods that are used to set the internal state of the
744object will return the object itself, so method calls can be conveniently
745chained together.
746
747Several styles of output are possible, all controlled by setting
748the C<Indent> flag. See L<Configuration Variables or Methods> below
749for details.
750
751
752=head2 Methods
753
754=over 4
755
756=item I<PACKAGE>->new(I<ARRAYREF [>, I<ARRAYREF]>)
757
758Returns a newly created C<Data::Dumper> object. The first argument is an
759anonymous array of values to be dumped. The optional second argument is an
760anonymous array of names for the values. The names need not have a leading
761C<$> sign, and must be comprised of alphanumeric characters. You can begin
762a name with a C<*> to specify that the dereferenced type must be dumped
763instead of the reference itself, for ARRAY and HASH references.
764
765The prefix specified by C<$Data::Dumper::Varname> will be used with a
766numeric suffix if the name for a value is undefined.
767
768Data::Dumper will catalog all references encountered while dumping the
769values. Cross-references (in the form of names of substructures in perl
770syntax) will be inserted at all possible points, preserving any structural
771interdependencies in the original set of values. Structure traversal is
772depth-first, and proceeds in order from the first supplied value to
773the last.
774
775=item I<$OBJ>->Dump I<or> I<PACKAGE>->Dump(I<ARRAYREF [>, I<ARRAYREF]>)
776
777Returns the stringified form of the values stored in the object (preserving
778the order in which they were supplied to C<new>), subject to the
779configuration options below. In a list context, it returns a list
780of strings corresponding to the supplied values.
781
782The second form, for convenience, simply calls the C<new> method on its
783arguments before dumping the object immediately.
784
785=item I<$OBJ>->Seen(I<[HASHREF]>)
786
787Queries or adds to the internal table of already encountered references.
788You must use C<Reset> to explicitly clear the table if needed. Such
789references are not dumped; instead, their names are inserted wherever they
790are encountered subsequently. This is useful especially for properly
791dumping subroutine references.
792
793Expects an anonymous hash of name => value pairs. Same rules apply for names
794as in C<new>. If no argument is supplied, will return the "seen" list of
795name => value pairs, in a list context. Otherwise, returns the object
796itself.
797
798=item I<$OBJ>->Values(I<[ARRAYREF]>)
799
800Queries or replaces the internal array of values that will be dumped.
801When called without arguments, returns the values. Otherwise, returns the
802object itself.
803
804=item I<$OBJ>->Names(I<[ARRAYREF]>)
805
806Queries or replaces the internal array of user supplied names for the values
807that will be dumped. When called without arguments, returns the names.
808Otherwise, returns the object itself.
809
810=item I<$OBJ>->Reset
811
812Clears the internal table of "seen" references and returns the object
813itself.
814
815=back
816
817=head2 Functions
818
819=over 4
820
821=item Dumper(I<LIST>)
822
823Returns the stringified form of the values in the list, subject to the
824configuration options below. The values will be named C<$VAR>I<n> in the
825output, where I<n> is a numeric suffix. Will return a list of strings
826in a list context.
827
828=back
829
830=head2 Configuration Variables or Methods
831
832Several configuration variables can be used to control the kind of output
833generated when using the procedural interface. These variables are usually
834C<local>ized in a block so that other parts of the code are not affected by
835the change.
836
837These variables determine the default state of the object created by calling
838the C<new> method, but cannot be used to alter the state of the object
839thereafter. The equivalent method names should be used instead to query
840or set the internal state of the object.
841
842The method forms return the object itself when called with arguments,
843so that they can be chained together nicely.
844
845=over 4
846
847=item *
848
849$Data::Dumper::Indent I<or> I<$OBJ>->Indent(I<[NEWVAL]>)
850
851Controls the style of indentation. It can be set to 0, 1, 2 or 3. Style 0
852spews output without any newlines, indentation, or spaces between list
853items. It is the most compact format possible that can still be called
854valid perl. Style 1 outputs a readable form with newlines but no fancy
855indentation (each level in the structure is simply indented by a fixed
856amount of whitespace). Style 2 (the default) outputs a very readable form
857which takes into account the length of hash keys (so the hash value lines
858up). Style 3 is like style 2, but also annotates the elements of arrays
859with their index (but the comment is on its own line, so array output
860consumes twice the number of lines). Style 2 is the default.
861
862=item *
863
864$Data::Dumper::Purity I<or> I<$OBJ>->Purity(I<[NEWVAL]>)
865
866Controls the degree to which the output can be C<eval>ed to recreate the
867supplied reference structures. Setting it to 1 will output additional perl
868statements that will correctly recreate nested references. The default is
8690.
870
871=item *
872
873$Data::Dumper::Pad I<or> I<$OBJ>->Pad(I<[NEWVAL]>)
874
875Specifies the string that will be prefixed to every line of the output.
876Empty string by default.
877
878=item *
879
880$Data::Dumper::Varname I<or> I<$OBJ>->Varname(I<[NEWVAL]>)
881
882Contains the prefix to use for tagging variable names in the output. The
883default is "VAR".
884
885=item *
886
887$Data::Dumper::Useqq I<or> I<$OBJ>->Useqq(I<[NEWVAL]>)
888
889When set, enables the use of double quotes for representing string values.
890Whitespace other than space will be represented as C<[\n\t\r]>, "unsafe"
891characters will be backslashed, and unprintable characters will be output as
892quoted octal integers. Since setting this variable imposes a performance
893penalty, the default is 0. C<Dump()> will run slower if this flag is set,
894since the fast XSUB implementation doesn't support it yet.
895
896=item *
897
898$Data::Dumper::Terse I<or> I<$OBJ>->Terse(I<[NEWVAL]>)
899
900When set, Data::Dumper will emit single, non-self-referential values as
901atoms/terms rather than statements. This means that the C<$VAR>I<n> names
902will be avoided where possible, but be advised that such output may not
903always be parseable by C<eval>.
904
905=item *
906
907$Data::Dumper::Freezer I<or> $I<OBJ>->Freezer(I<[NEWVAL]>)
908
909Can be set to a method name, or to an empty string to disable the feature.
910Data::Dumper will invoke that method via the object before attempting to
911stringify it. This method can alter the contents of the object (if, for
912instance, it contains data allocated from C), and even rebless it in a
913different package. The client is responsible for making sure the specified
914method can be called via the object, and that the object ends up containing
915only perl data types after the method has been called. Defaults to an empty
916string.
917
918If an object does not support the method specified (determined using
919UNIVERSAL::can()) then the call will be skipped. If the method dies a
920warning will be generated.
921
922=item *
923
924$Data::Dumper::Toaster I<or> $I<OBJ>->Toaster(I<[NEWVAL]>)
925
926Can be set to a method name, or to an empty string to disable the feature.
927Data::Dumper will emit a method call for any objects that are to be dumped
928using the syntax C<bless(DATA, CLASS)-E<gt>METHOD()>. Note that this means that
929the method specified will have to perform any modifications required on the
930object (like creating new state within it, and/or reblessing it in a
931different package) and then return it. The client is responsible for making
932sure the method can be called via the object, and that it returns a valid
933object. Defaults to an empty string.
934
935=item *
936
937$Data::Dumper::Deepcopy I<or> $I<OBJ>->Deepcopy(I<[NEWVAL]>)
938
939Can be set to a boolean value to enable deep copies of structures.
940Cross-referencing will then only be done when absolutely essential
941(i.e., to break reference cycles). Default is 0.
942
943=item *
944
945$Data::Dumper::Quotekeys I<or> $I<OBJ>->Quotekeys(I<[NEWVAL]>)
946
947Can be set to a boolean value to control whether hash keys are quoted.
948A false value will avoid quoting hash keys when it looks like a simple
949string. Default is 1, which will always enclose hash keys in quotes.
950
951=item *
952
953$Data::Dumper::Bless I<or> $I<OBJ>->Bless(I<[NEWVAL]>)
954
955Can be set to a string that specifies an alternative to the C<bless>
956builtin operator used to create objects. A function with the specified
957name should exist, and should accept the same arguments as the builtin.
958Default is C<bless>.
959
960=item *
961
962$Data::Dumper::Pair I<or> $I<OBJ>->Pair(I<[NEWVAL]>)
963
964Can be set to a string that specifies the separator between hash keys
965and values. To dump nested hash, array and scalar values to JavaScript,
966use: C<$Data::Dumper::Pair = ' : ';>. Implementing C<bless> in JavaScript
967is left as an exercise for the reader.
968A function with the specified name exists, and accepts the same arguments
969as the builtin.
970
971Default is: C< =E<gt> >.
972
973=item *
974
975$Data::Dumper::Maxdepth I<or> $I<OBJ>->Maxdepth(I<[NEWVAL]>)
976
977Can be set to a positive integer that specifies the depth beyond which
978which we don't venture into a structure. Has no effect when
979C<Data::Dumper::Purity> is set. (Useful in debugger when we often don't
980want to see more than enough). Default is 0, which means there is
981no maximum depth.
982
983=item *
984
985$Data::Dumper::Useperl I<or> $I<OBJ>->Useperl(I<[NEWVAL]>)
986
987Can be set to a boolean value which controls whether the pure Perl
988implementation of C<Data::Dumper> is used. The C<Data::Dumper> module is
989a dual implementation, with almost all functionality written in both
990pure Perl and also in XS ('C'). Since the XS version is much faster, it
991will always be used if possible. This option lets you override the
992default behavior, usually for testing purposes only. Default is 0, which
993means the XS implementation will be used if possible.
994
995=item *
996
997$Data::Dumper::Sortkeys I<or> $I<OBJ>->Sortkeys(I<[NEWVAL]>)
998
999Can be set to a boolean value to control whether hash keys are dumped in
1000sorted order. A true value will cause the keys of all hashes to be
1001dumped in Perl's default sort order. Can also be set to a subroutine
1002reference which will be called for each hash that is dumped. In this
1003case C<Data::Dumper> will call the subroutine once for each hash,
1004passing it the reference of the hash. The purpose of the subroutine is
1005to return a reference to an array of the keys that will be dumped, in
1006the order that they should be dumped. Using this feature, you can
1007control both the order of the keys, and which keys are actually used. In
1008other words, this subroutine acts as a filter by which you can exclude
1009certain keys from being dumped. Default is 0, which means that hash keys
1010are not sorted.
1011
1012=item *
1013
1014$Data::Dumper::Deparse I<or> $I<OBJ>->Deparse(I<[NEWVAL]>)
1015
1016Can be set to a boolean value to control whether code references are
1017turned into perl source code. If set to a true value, C<B::Deparse>
1018will be used to get the source of the code reference. Using this option
1019will force using the Perl implementation of the dumper, since the fast
1020XSUB implementation doesn't support it.
1021
1022Caution : use this option only if you know that your coderefs will be
1023properly reconstructed by C<B::Deparse>.
1024
1025=back
1026
1027=head2 Exports
1028
1029=over 4
1030
1031=item Dumper
1032
1033=back
1034
1035=head1 EXAMPLES
1036
1037Run these code snippets to get a quick feel for the behavior of this
1038module. When you are through with these examples, you may want to
1039add or change the various configuration variables described above,
1040to see their behavior. (See the testsuite in the Data::Dumper
1041distribution for more examples.)
1042
1043
1044 use Data::Dumper;
1045
1046 package Foo;
1047 sub new {bless {'a' => 1, 'b' => sub { return "foo" }}, $_[0]};
1048
1049 package Fuz; # a weird REF-REF-SCALAR object
1050 sub new {bless \($_ = \ 'fu\'z'), $_[0]};
1051
1052 package main;
1053 $foo = Foo->new;
1054 $fuz = Fuz->new;
1055 $boo = [ 1, [], "abcd", \*foo,
1056 {1 => 'a', 023 => 'b', 0x45 => 'c'},
1057 \\"p\q\'r", $foo, $fuz];
1058
1059 ########
1060 # simple usage
1061 ########
1062
1063 $bar = eval(Dumper($boo));
1064 print($@) if $@;
1065 print Dumper($boo), Dumper($bar); # pretty print (no array indices)
1066
1067 $Data::Dumper::Terse = 1; # don't output names where feasible
1068 $Data::Dumper::Indent = 0; # turn off all pretty print
1069 print Dumper($boo), "\n";
1070
1071 $Data::Dumper::Indent = 1; # mild pretty print
1072 print Dumper($boo);
1073
1074 $Data::Dumper::Indent = 3; # pretty print with array indices
1075 print Dumper($boo);
1076
1077 $Data::Dumper::Useqq = 1; # print strings in double quotes
1078 print Dumper($boo);
1079
1080 $Data::Dumper::Pair = " : "; # specify hash key/value separator
1081 print Dumper($boo);
1082
1083
1084 ########
1085 # recursive structures
1086 ########
1087
1088 @c = ('c');
1089 $c = \@c;
1090 $b = {};
1091 $a = [1, $b, $c];
1092 $b->{a} = $a;
1093 $b->{b} = $a->[1];
1094 $b->{c} = $a->[2];
1095 print Data::Dumper->Dump([$a,$b,$c], [qw(a b c)]);
1096
1097
1098 $Data::Dumper::Purity = 1; # fill in the holes for eval
1099 print Data::Dumper->Dump([$a, $b], [qw(*a b)]); # print as @a
1100 print Data::Dumper->Dump([$b, $a], [qw(*b a)]); # print as %b
1101
1102
1103 $Data::Dumper::Deepcopy = 1; # avoid cross-refs
1104 print Data::Dumper->Dump([$b, $a], [qw(*b a)]);
1105
1106
1107 $Data::Dumper::Purity = 0; # avoid cross-refs
1108 print Data::Dumper->Dump([$b, $a], [qw(*b a)]);
1109
1110 ########
1111 # deep structures
1112 ########
1113
1114 $a = "pearl";
1115 $b = [ $a ];
1116 $c = { 'b' => $b };
1117 $d = [ $c ];
1118 $e = { 'd' => $d };
1119 $f = { 'e' => $e };
1120 print Data::Dumper->Dump([$f], [qw(f)]);
1121
1122 $Data::Dumper::Maxdepth = 3; # no deeper than 3 refs down
1123 print Data::Dumper->Dump([$f], [qw(f)]);
1124
1125
1126 ########
1127 # object-oriented usage
1128 ########
1129
1130 $d = Data::Dumper->new([$a,$b], [qw(a b)]);
1131 $d->Seen({'*c' => $c}); # stash a ref without printing it
1132 $d->Indent(3);
1133 print $d->Dump;
1134 $d->Reset->Purity(0); # empty the seen cache
1135 print join "----\n", $d->Dump;
1136
1137
1138 ########
1139 # persistence
1140 ########
1141
1142 package Foo;
1143 sub new { bless { state => 'awake' }, shift }
1144 sub Freeze {
1145 my $s = shift;
1146 print STDERR "preparing to sleep\n";
1147 $s->{state} = 'asleep';
1148 return bless $s, 'Foo::ZZZ';
1149 }
1150
1151 package Foo::ZZZ;
1152 sub Thaw {
1153 my $s = shift;
1154 print STDERR "waking up\n";
1155 $s->{state} = 'awake';
1156 return bless $s, 'Foo';
1157 }
1158
1159 package Foo;
1160 use Data::Dumper;
1161 $a = Foo->new;
1162 $b = Data::Dumper->new([$a], ['c']);
1163 $b->Freezer('Freeze');
1164 $b->Toaster('Thaw');
1165 $c = $b->Dump;
1166 print $c;
1167 $d = eval $c;
1168 print Data::Dumper->Dump([$d], ['d']);
1169
1170
1171 ########
1172 # symbol substitution (useful for recreating CODE refs)
1173 ########
1174
1175 sub foo { print "foo speaking\n" }
1176 *other = \&foo;
1177 $bar = [ \&other ];
1178 $d = Data::Dumper->new([\&other,$bar],['*other','bar']);
1179 $d->Seen({ '*foo' => \&foo });
1180 print $d->Dump;
1181
1182
1183 ########
1184 # sorting and filtering hash keys
1185 ########
1186
1187 $Data::Dumper::Sortkeys = \&my_filter;
1188 my $foo = { map { (ord, "$_$_$_") } 'I'..'Q' };
1189 my $bar = { %$foo };
1190 my $baz = { reverse %$foo };
1191 print Dumper [ $foo, $bar, $baz ];
1192
1193 sub my_filter {
1194 my ($hash) = @_;
1195 # return an array ref containing the hash keys to dump
1196 # in the order that you want them to be dumped
1197 return [
1198 # Sort the keys of %$foo in reverse numeric order
1199 $hash eq $foo ? (sort {$b <=> $a} keys %$hash) :
1200 # Only dump the odd number keys of %$bar
1201 $hash eq $bar ? (grep {$_ % 2} keys %$hash) :
1202 # Sort keys in default order for all other hashes
1203 (sort keys %$hash)
1204 ];
1205 }
1206
1207=head1 BUGS
1208
1209Due to limitations of Perl subroutine call semantics, you cannot pass an
1210array or hash. Prepend it with a C<\> to pass its reference instead. This
1211will be remedied in time, now that Perl has subroutine prototypes.
1212For now, you need to use the extended usage form, and prepend the
1213name with a C<*> to output it as a hash or array.
1214
1215C<Data::Dumper> cheats with CODE references. If a code reference is
1216encountered in the structure being processed (and if you haven't set
1217the C<Deparse> flag), an anonymous subroutine that
1218contains the string '"DUMMY"' will be inserted in its place, and a warning
1219will be printed if C<Purity> is set. You can C<eval> the result, but bear
1220in mind that the anonymous sub that gets created is just a placeholder.
1221Someday, perl will have a switch to cache-on-demand the string
1222representation of a compiled piece of code, I hope. If you have prior
1223knowledge of all the code refs that your data structures are likely
1224to have, you can use the C<Seen> method to pre-seed the internal reference
1225table and make the dumped output point to them, instead. See L</EXAMPLES>
1226above.
1227
1228The C<Useqq> and C<Deparse> flags makes Dump() run slower, since the
1229XSUB implementation does not support them.
1230
1231SCALAR objects have the weirdest looking C<bless> workaround.
1232
1233Pure Perl version of C<Data::Dumper> escapes UTF-8 strings correctly
1234only in Perl 5.8.0 and later.
1235
1236=head2 NOTE
1237
1238Starting from Perl 5.8.1 different runs of Perl will have different
1239ordering of hash keys. The change was done for greater security,
1240see L<perlsec/"Algorithmic Complexity Attacks">. This means that
1241different runs of Perl will have different Data::Dumper outputs if
1242the data contains hashes. If you need to have identical Data::Dumper
1243outputs from different runs of Perl, use the environment variable
1244PERL_HASH_SEED, see L<perlrun/PERL_HASH_SEED>. Using this restores
1245the old (platform-specific) ordering: an even prettier solution might
1246be to use the C<Sortkeys> filter of Data::Dumper.
1247
1248=head1 AUTHOR
1249
1250Gurusamy Sarathy [email protected]
1251
1252Copyright (c) 1996-98 Gurusamy Sarathy. All rights reserved.
1253This program is free software; you can redistribute it and/or
1254modify it under the same terms as Perl itself.
1255
1256=head1 VERSION
1257
1258Version 2.121 (Aug 24 2003)
1259
1260=head1 SEE ALSO
1261
1262perl(1)
1263
1264=cut
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