4 # convert perl data structures into perl syntax suitable for both printing
7 # Documentation at the __END__
12 $VERSION = '2.121_10';
25 @EXPORT_OK = qw(DumperX);
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.
36 XSLoader::load( 'Data::Dumper' ) unless $Useperl;
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;
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.
66 croak "Usage: PACKAGE->new(ARRAYREF, [ARRAYREF])"
67 unless (defined($v) && (ref($v) eq 'ARRAY'));
68 $n = [] unless (defined($n) && (ref($v) eq 'ARRAY'));
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 => $Deparse, # use B::Deparse for coderefs
101 return bless($s, $c);
105 # Packed numeric addresses take less memory. Plus pack is faster than sprintf
106 *init_refaddr_format = sub {};
108 *format_refaddr = sub {
109 require Scalar::Util;
110 pack "J", Scalar::Util::refaddr(shift);
113 *init_refaddr_format = sub {
115 my $f = $Config::Config{uvxformat};
117 our $refaddr_format = "0x%" . $f;
120 *format_refaddr = sub {
121 require Scalar::Util;
122 sprintf our $refaddr_format, Scalar::Util::refaddr(shift);
127 # add-to or query the table of already seen references
131 if (defined($g) && (ref($g) eq 'HASH')) {
132 init_refaddr_format();
134 while (($k, $v) = each %$g) {
135 if (defined $v and ref $v) {
136 $id = format_refaddr($v);
137 if ($k =~ /^[*](.*)$/) {
138 $k = (ref $v eq 'ARRAY') ? ( "\\\@" . $1 ) :
139 (ref $v eq 'HASH') ? ( "\\\%" . $1 ) :
140 (ref $v eq 'CODE') ? ( "\\\&" . $1 ) :
143 elsif ($k !~ /^\$/) {
146 $s->{seen}{$id} = [$k, $v];
149 carp "Only refs supported, ignoring non-ref item \$$k";
155 return map { @$_ } values %{$s->{seen}};
160 # set or query the values to be dumped
164 if (defined($v) && (ref($v) eq 'ARRAY')) {
165 $s->{todump} = [@$v]; # make a copy
169 return @{$s->{todump}};
174 # set or query the names of the values to be dumped
178 if (defined($n) && (ref($n) eq 'ARRAY')) {
179 $s->{names} = [@$n]; # make a copy
183 return @{$s->{names}};
191 unless $Data::Dumper::Useperl || (ref($_[0]) && $_[0]->{useperl}) ||
192 $Data::Dumper::Useqq || (ref($_[0]) && $_[0]->{useqq}) ||
193 $Data::Dumper::Deparse || (ref($_[0]) && $_[0]->{deparse});
198 # dump the refs in the current dumper object.
199 # expects same args as new() if called via package name.
203 my(@out, $val, $name);
206 init_refaddr_format();
208 $s = $s->new(@_) unless ref $s;
210 for $val (@{$s->{todump}}) {
213 $name = $s->{names}[$i++];
215 if ($name =~ /^[*](.*)$/) {
217 $name = (ref $val eq 'ARRAY') ? ( "\@" . $1 ) :
218 (ref $val eq 'HASH') ? ( "\%" . $1 ) :
219 (ref $val eq 'CODE') ? ( "\*" . $1 ) :
226 elsif ($name !~ /^\$/) {
227 $name = "\$" . $name;
231 $name = "\$" . $s->{varname} . $i;
236 local($s->{apad}) = $s->{apad};
237 $s->{apad} .= ' ' x (length($name) + 3) if $s->{indent} >= 2;
238 $valstr = $s->_dump($val, $name);
241 $valstr = "$name = " . $valstr . ';' if @post or !$s->{terse};
242 $out .= $s->{pad} . $valstr . $s->{sep};
243 $out .= $s->{pad} . join(';' . $s->{sep} . $s->{pad}, @post)
244 . ';' . $s->{sep} if @post;
248 return wantarray ? @out : join('', @out);
252 # twist, toil and turn;
253 # and recurse, of course.
254 # sometimes sordidly;
255 # and curse if no recourse.
258 my($s, $val, $name) = @_;
260 my($out, $realpack, $realtype, $type, $ipad, $id, $blesspad);
267 # Call the freezer method if it's specified and the object has the
268 # method. Trap errors and warn() instead of die()ing, like the XS
270 my $freezer = $s->{freezer};
271 if ($freezer and UNIVERSAL::can($val, $freezer)) {
272 eval { $val->$freezer() };
273 warn "WARNING(Freezer method call failed): $@" if $@;
276 require Scalar::Util;
277 $realpack = Scalar::Util::blessed($val);
278 $realtype = $realpack ? Scalar::Util::reftype($val) : ref $val;
279 $id = format_refaddr($val);
281 # if it has a name, we need to either look it up, or keep a tab
282 # on it so we know when we hit it later
283 if (defined($name) and length($name)) {
284 # keep a tab on it so that we dont fall into recursive pit
285 if (exists $s->{seen}{$id}) {
286 # if ($s->{expdepth} < $s->{level}) {
287 if ($s->{purity} and $s->{level} > 0) {
288 $out = ($realtype eq 'HASH') ? '{}' :
289 ($realtype eq 'ARRAY') ? '[]' :
291 push @post, $name . " = " . $s->{seen}{$id}[0];
294 $out = $s->{seen}{$id}[0];
295 if ($name =~ /^([\@\%])/) {
297 if ($out =~ /^\\$start/) {
298 $out = substr($out, 1);
301 $out = $start . '{' . $out . '}';
310 $s->{seen}{$id} = [ (($name =~ /^[@%]/) ? ('\\' . $name ) :
311 ($realtype eq 'CODE' and
312 $name =~ /^[*](.*)$/) ? ('\\&' . $1 ) :
318 if ($realpack and $realpack eq 'Regexp') {
324 # If purity is not set and maxdepth is set, then check depth:
325 # if we have reached maximum depth, return the string
326 # representation of the thing we are currently examining
327 # at this depth (i.e., 'Foo=ARRAY(0xdeadbeef)').
329 and $s->{maxdepth} > 0
330 and $s->{level} >= $s->{maxdepth})
335 # we have a blessed ref
337 $out = $s->{'bless'} . '( ';
338 $blesspad = $s->{apad};
339 $s->{apad} .= ' ' if ($s->{indent} >= 2);
343 $ipad = $s->{xpad} x $s->{level};
345 if ($realtype eq 'SCALAR' || $realtype eq 'REF') {
347 $out .= 'do{\\(my $o = ' . $s->_dump($$val, "\${$name}") . ')}';
350 $out .= '\\' . $s->_dump($$val, "\${$name}");
353 elsif ($realtype eq 'GLOB') {
354 $out .= '\\' . $s->_dump($$val, "*{$name}");
356 elsif ($realtype eq 'ARRAY') {
357 my($v, $pad, $mname);
359 $out .= ($name =~ /^\@/) ? '(' : '[';
360 $pad = $s->{sep} . $s->{pad} . $s->{apad};
361 ($name =~ /^\@(.*)$/) ? ($mname = "\$" . $1) :
362 # omit -> if $foo->[0]->{bar}, but not ${$foo->[0]}->{bar}
363 ($name =~ /^\\?[\%\@\*\$][^{].*[]}]$/) ? ($mname = $name) :
364 ($mname = $name . '->');
365 $mname .= '->' if $mname =~ /^\*.+\{[A-Z]+\}$/;
367 $sname = $mname . '[' . $i . ']';
368 $out .= $pad . $ipad . '#' . $i if $s->{indent} >= 3;
369 $out .= $pad . $ipad . $s->_dump($v, $sname);
370 $out .= "," if $i++ < $#$val;
372 $out .= $pad . ($s->{xpad} x ($s->{level} - 1)) if $i;
373 $out .= ($name =~ /^\@/) ? ')' : ']';
375 elsif ($realtype eq 'HASH') {
376 my($k, $v, $pad, $lpad, $mname, $pair);
377 $out .= ($name =~ /^\%/) ? '(' : '{';
378 $pad = $s->{sep} . $s->{pad} . $s->{apad};
381 ($name =~ /^\%(.*)$/) ? ($mname = "\$" . $1) :
382 # omit -> if $foo->[0]->{bar}, but not ${$foo->[0]}->{bar}
383 ($name =~ /^\\?[\%\@\*\$][^{].*[]}]$/) ? ($mname = $name) :
384 ($mname = $name . '->');
385 $mname .= '->' if $mname =~ /^\*.+\{[A-Z]+\}$/;
386 my ($sortkeys, $keys, $key) = ("$s->{sortkeys}");
388 if (ref($s->{sortkeys}) eq 'CODE') {
389 $keys = $s->{sortkeys}($val);
390 unless (ref($keys) eq 'ARRAY') {
391 carp "Sortkeys subroutine did not return ARRAYREF";
396 $keys = [ sort keys %$val ];
399 while (($k, $v) = ! $sortkeys ? (each %$val) :
400 @$keys ? ($key = shift(@$keys), $val->{$key}) :
403 my $nk = $s->_dump($k, "");
404 $nk = $1 if !$s->{quotekeys} and $nk =~ /^[\"\']([A-Za-z_]\w*)[\"\']$/;
405 $sname = $mname . '{' . $nk . '}';
406 $out .= $pad . $ipad . $nk . $pair;
408 # temporarily alter apad
409 $s->{apad} .= (" " x (length($nk) + 4)) if $s->{indent} >= 2;
410 $out .= $s->_dump($val->{$k}, $sname) . ",";
411 $s->{apad} = $lpad if $s->{indent} >= 2;
413 if (substr($out, -1) eq ',') {
415 $out .= $pad . ($s->{xpad} x ($s->{level} - 1));
417 $out .= ($name =~ /^\%/) ? ')' : '}';
419 elsif ($realtype eq 'CODE') {
422 my $sub = 'sub ' . (B::Deparse->new)->coderef2text($val);
423 $pad = $s->{sep} . $s->{pad} . $s->{apad} . $s->{xpad} x ($s->{level} - 1);
424 $sub =~ s/\n/$pad/gse;
427 $out .= 'sub { "DUMMY" }';
428 carp "Encountered CODE ref, using dummy placeholder" if $s->{purity};
432 croak "Can\'t handle $realtype type.";
435 if ($realpack) { # we have a blessed ref
436 $out .= ', \'' . $realpack . '\'' . ' )';
437 $out .= '->' . $s->{toaster} . '()' if $s->{toaster} ne '';
438 $s->{apad} = $blesspad;
443 else { # simple scalar
446 # first, catalog the scalar
448 $id = format_refaddr($ref);
449 if (exists $s->{seen}{$id}) {
450 if ($s->{seen}{$id}[2]) {
451 $out = $s->{seen}{$id}[0];
457 #warn "[>\\$name]\n";
458 $s->{seen}{$id} = ["\\$name", $ref];
461 if (ref($ref) eq 'GLOB' or "$ref" =~ /=GLOB\([^()]+\)$/) { # glob
462 my $name = substr($val, 1);
463 if ($name =~ /^[A-Za-z_][\w:]*$/) {
464 $name =~ s/^main::/::/;
468 $sname = $s->_dump($name, "");
469 $sname = '{' . $sname . '}';
473 local ($s->{level}) = 0;
474 for $k (qw(SCALAR ARRAY HASH)) {
475 my $gval = *$val{$k};
476 next unless defined $gval;
477 next if $k eq "SCALAR" && ! defined $$gval; # always there
479 # _dump can push into @post, so we hold our place using $postlen
480 my $postlen = scalar @post;
481 $post[$postlen] = "\*$sname = ";
482 local ($s->{apad}) = " " x length($post[$postlen]) if $s->{indent} >= 2;
483 $post[$postlen] .= $s->_dump($gval, "\*$sname\{$k\}");
486 $out .= '*' . $sname;
488 elsif (!defined($val)) {
491 elsif ($val =~ /^(?:0|-?[1-9]\d{0,8})\z/) { # safe decimal number
495 if ($s->{useqq} or $val =~ tr/\0-\377//c) {
496 # Fall back to qq if there's unicode
497 $out .= qquote($val, $s->{useqq});
500 $val =~ s/([\\\'])/\\$1/g;
501 $out .= '\'' . $val . '\'';
506 # if we made it this far, $id was added to seen list at current
507 # level, so remove it to get deep copies
508 if ($s->{deepcopy}) {
509 delete($s->{seen}{$id});
512 $s->{seen}{$id}[2] = 1;
519 # non-OO style of earlier version
522 return Data::Dumper->Dump([@_]);
527 return Data::Dumper->Dumpxs([@_], []);
530 sub Dumpf { return Data::Dumper->Dump(@_) }
532 sub Dumpp { print Data::Dumper->Dump(@_) }
535 # reset the "seen" cache
564 defined($v) ? (($s->{pair} = $v), return $s) : $s->{pair};
569 defined($v) ? (($s->{pad} = $v), return $s) : $s->{pad};
574 defined($v) ? (($s->{varname} = $v), return $s) : $s->{varname};
579 defined($v) ? (($s->{purity} = $v), return $s) : $s->{purity};
584 defined($v) ? (($s->{useqq} = $v), return $s) : $s->{useqq};
589 defined($v) ? (($s->{terse} = $v), return $s) : $s->{terse};
594 defined($v) ? (($s->{freezer} = $v), return $s) : $s->{freezer};
599 defined($v) ? (($s->{toaster} = $v), return $s) : $s->{toaster};
604 defined($v) ? (($s->{deepcopy} = $v), return $s) : $s->{deepcopy};
609 defined($v) ? (($s->{quotekeys} = $v), return $s) : $s->{quotekeys};
614 defined($v) ? (($s->{'bless'} = $v), return $s) : $s->{'bless'};
619 defined($v) ? (($s->{'maxdepth'} = $v), return $s) : $s->{'maxdepth'};
624 defined($v) ? (($s->{'useperl'} = $v), return $s) : $s->{'useperl'};
629 defined($v) ? (($s->{'sortkeys'} = $v), return $s) : $s->{'sortkeys'};
634 defined($v) ? (($s->{'deparse'} = $v), return $s) : $s->{'deparse'};
637 # used by qquote below
648 # put a string value in double quotes
651 s/([\\\"\@\$])/\\$1/g;
652 my $bytes; { use bytes; $bytes = length }
653 s/([^\x00-\x7f])/'\x{'.sprintf("%x",ord($1)).'}'/ge if $bytes > length;
654 return qq("$_") unless
655 /[^ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~]/; # fast exit
657 my $high = shift || "";
658 s/([\a\b\t\n\f\r\e])/$esc{$1}/g;
660 if (ord('^')==94) { # ascii
661 # no need for 3 digits in escape for these
662 s/([\0-\037])(?!\d)/'\\'.sprintf('%o',ord($1))/eg;
663 s/([\0-\037\177])/'\\'.sprintf('%03o',ord($1))/eg;
664 # all but last branch below not supported --BEHAVIOR SUBJECT TO CHANGE--
665 if ($high eq "iso8859") {
666 s/([\200-\240])/'\\'.sprintf('%o',ord($1))/eg;
667 } elsif ($high eq "utf8") {
669 # $str =~ s/([^\040-\176])/sprintf "\\x{%04x}", ord($1)/ge;
670 } elsif ($high eq "8bit") {
673 s/([\200-\377])/'\\'.sprintf('%03o',ord($1))/eg;
674 s/([^\040-\176])/sprintf "\\x{%04x}", ord($1)/ge;
678 s{([^ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~])(?!\d)}
679 {my $v = ord($1); '\\'.sprintf(($v <= 037 ? '%o' : '%03o'), $v)}eg;
680 s{([^ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~])}
681 {'\\'.sprintf('%03o',ord($1))}eg;
687 # helper sub to sort hash keys in Perl < 5.8.0 where we don't have
688 # access to sortsv() from XS
689 sub _sortkeys { [ sort keys %{$_[0]} ] }
696 Data::Dumper - stringified perl data structures, suitable for both printing and C<eval>
702 # simple procedural interface
703 print Dumper($foo, $bar);
705 # extended usage with names
706 print Data::Dumper->Dump([$foo, $bar], [qw(foo *ary)]);
708 # configuration variables
710 local $Data::Dumper::Purity = 1;
711 eval Data::Dumper->Dump([$foo, $bar], [qw(foo *ary)]);
715 $d = Data::Dumper->new([$foo, $bar], [qw(foo *ary)]);
719 $d->Purity(1)->Terse(1)->Deepcopy(1);
725 Given a list of scalars or reference variables, writes out their contents in
726 perl syntax. The references can also be objects. The contents of each
727 variable is output in a single Perl statement. Handles self-referential
728 structures correctly.
730 The return value can be C<eval>ed to get back an identical copy of the
731 original reference structure.
733 Any references that are the same as one of those passed in will be named
734 C<$VAR>I<n> (where I<n> is a numeric suffix), and other duplicate references
735 to substructures within C<$VAR>I<n> will be appropriately labeled using arrow
736 notation. You can specify names for individual values to be dumped if you
737 use the C<Dump()> method, or you can change the default C<$VAR> prefix to
738 something else. See C<$Data::Dumper::Varname> and C<$Data::Dumper::Terse>
741 The default output of self-referential structures can be C<eval>ed, but the
742 nested references to C<$VAR>I<n> will be undefined, since a recursive
743 structure cannot be constructed using one Perl statement. You should set the
744 C<Purity> flag to 1 to get additional statements that will correctly fill in
745 these references. Moreover, if C<eval>ed when strictures are in effect,
746 you need to ensure that any variables it accesses are previously declared.
748 In the extended usage form, the references to be dumped can be given
749 user-specified names. If a name begins with a C<*>, the output will
750 describe the dereferenced type of the supplied reference for hashes and
751 arrays, and coderefs. Output of names will be avoided where possible if
752 the C<Terse> flag is set.
754 In many cases, methods that are used to set the internal state of the
755 object will return the object itself, so method calls can be conveniently
758 Several styles of output are possible, all controlled by setting
759 the C<Indent> flag. See L<Configuration Variables or Methods> below
767 =item I<PACKAGE>->new(I<ARRAYREF [>, I<ARRAYREF]>)
769 Returns a newly created C<Data::Dumper> object. The first argument is an
770 anonymous array of values to be dumped. The optional second argument is an
771 anonymous array of names for the values. The names need not have a leading
772 C<$> sign, and must be comprised of alphanumeric characters. You can begin
773 a name with a C<*> to specify that the dereferenced type must be dumped
774 instead of the reference itself, for ARRAY and HASH references.
776 The prefix specified by C<$Data::Dumper::Varname> will be used with a
777 numeric suffix if the name for a value is undefined.
779 Data::Dumper will catalog all references encountered while dumping the
780 values. Cross-references (in the form of names of substructures in perl
781 syntax) will be inserted at all possible points, preserving any structural
782 interdependencies in the original set of values. Structure traversal is
783 depth-first, and proceeds in order from the first supplied value to
786 =item I<$OBJ>->Dump I<or> I<PACKAGE>->Dump(I<ARRAYREF [>, I<ARRAYREF]>)
788 Returns the stringified form of the values stored in the object (preserving
789 the order in which they were supplied to C<new>), subject to the
790 configuration options below. In a list context, it returns a list
791 of strings corresponding to the supplied values.
793 The second form, for convenience, simply calls the C<new> method on its
794 arguments before dumping the object immediately.
796 =item I<$OBJ>->Seen(I<[HASHREF]>)
798 Queries or adds to the internal table of already encountered references.
799 You must use C<Reset> to explicitly clear the table if needed. Such
800 references are not dumped; instead, their names are inserted wherever they
801 are encountered subsequently. This is useful especially for properly
802 dumping subroutine references.
804 Expects an anonymous hash of name => value pairs. Same rules apply for names
805 as in C<new>. If no argument is supplied, will return the "seen" list of
806 name => value pairs, in a list context. Otherwise, returns the object
809 =item I<$OBJ>->Values(I<[ARRAYREF]>)
811 Queries or replaces the internal array of values that will be dumped.
812 When called without arguments, returns the values. Otherwise, returns the
815 =item I<$OBJ>->Names(I<[ARRAYREF]>)
817 Queries or replaces the internal array of user supplied names for the values
818 that will be dumped. When called without arguments, returns the names.
819 Otherwise, returns the object itself.
823 Clears the internal table of "seen" references and returns the object
832 =item Dumper(I<LIST>)
834 Returns the stringified form of the values in the list, subject to the
835 configuration options below. The values will be named C<$VAR>I<n> in the
836 output, where I<n> is a numeric suffix. Will return a list of strings
841 =head2 Configuration Variables or Methods
843 Several configuration variables can be used to control the kind of output
844 generated when using the procedural interface. These variables are usually
845 C<local>ized in a block so that other parts of the code are not affected by
848 These variables determine the default state of the object created by calling
849 the C<new> method, but cannot be used to alter the state of the object
850 thereafter. The equivalent method names should be used instead to query
851 or set the internal state of the object.
853 The method forms return the object itself when called with arguments,
854 so that they can be chained together nicely.
860 $Data::Dumper::Indent I<or> I<$OBJ>->Indent(I<[NEWVAL]>)
862 Controls the style of indentation. It can be set to 0, 1, 2 or 3. Style 0
863 spews output without any newlines, indentation, or spaces between list
864 items. It is the most compact format possible that can still be called
865 valid perl. Style 1 outputs a readable form with newlines but no fancy
866 indentation (each level in the structure is simply indented by a fixed
867 amount of whitespace). Style 2 (the default) outputs a very readable form
868 which takes into account the length of hash keys (so the hash value lines
869 up). Style 3 is like style 2, but also annotates the elements of arrays
870 with their index (but the comment is on its own line, so array output
871 consumes twice the number of lines). Style 2 is the default.
875 $Data::Dumper::Purity I<or> I<$OBJ>->Purity(I<[NEWVAL]>)
877 Controls the degree to which the output can be C<eval>ed to recreate the
878 supplied reference structures. Setting it to 1 will output additional perl
879 statements that will correctly recreate nested references. The default is
884 $Data::Dumper::Pad I<or> I<$OBJ>->Pad(I<[NEWVAL]>)
886 Specifies the string that will be prefixed to every line of the output.
887 Empty string by default.
891 $Data::Dumper::Varname I<or> I<$OBJ>->Varname(I<[NEWVAL]>)
893 Contains the prefix to use for tagging variable names in the output. The
898 $Data::Dumper::Useqq I<or> I<$OBJ>->Useqq(I<[NEWVAL]>)
900 When set, enables the use of double quotes for representing string values.
901 Whitespace other than space will be represented as C<[\n\t\r]>, "unsafe"
902 characters will be backslashed, and unprintable characters will be output as
903 quoted octal integers. Since setting this variable imposes a performance
904 penalty, the default is 0. C<Dump()> will run slower if this flag is set,
905 since the fast XSUB implementation doesn't support it yet.
909 $Data::Dumper::Terse I<or> I<$OBJ>->Terse(I<[NEWVAL]>)
911 When set, Data::Dumper will emit single, non-self-referential values as
912 atoms/terms rather than statements. This means that the C<$VAR>I<n> names
913 will be avoided where possible, but be advised that such output may not
914 always be parseable by C<eval>.
918 $Data::Dumper::Freezer I<or> $I<OBJ>->Freezer(I<[NEWVAL]>)
920 Can be set to a method name, or to an empty string to disable the feature.
921 Data::Dumper will invoke that method via the object before attempting to
922 stringify it. This method can alter the contents of the object (if, for
923 instance, it contains data allocated from C), and even rebless it in a
924 different package. The client is responsible for making sure the specified
925 method can be called via the object, and that the object ends up containing
926 only perl data types after the method has been called. Defaults to an empty
929 If an object does not support the method specified (determined using
930 UNIVERSAL::can()) then the call will be skipped. If the method dies a
931 warning will be generated.
935 $Data::Dumper::Toaster I<or> $I<OBJ>->Toaster(I<[NEWVAL]>)
937 Can be set to a method name, or to an empty string to disable the feature.
938 Data::Dumper will emit a method call for any objects that are to be dumped
939 using the syntax C<bless(DATA, CLASS)-E<gt>METHOD()>. Note that this means that
940 the method specified will have to perform any modifications required on the
941 object (like creating new state within it, and/or reblessing it in a
942 different package) and then return it. The client is responsible for making
943 sure the method can be called via the object, and that it returns a valid
944 object. Defaults to an empty string.
948 $Data::Dumper::Deepcopy I<or> $I<OBJ>->Deepcopy(I<[NEWVAL]>)
950 Can be set to a boolean value to enable deep copies of structures.
951 Cross-referencing will then only be done when absolutely essential
952 (i.e., to break reference cycles). Default is 0.
956 $Data::Dumper::Quotekeys I<or> $I<OBJ>->Quotekeys(I<[NEWVAL]>)
958 Can be set to a boolean value to control whether hash keys are quoted.
959 A false value will avoid quoting hash keys when it looks like a simple
960 string. Default is 1, which will always enclose hash keys in quotes.
964 $Data::Dumper::Bless I<or> $I<OBJ>->Bless(I<[NEWVAL]>)
966 Can be set to a string that specifies an alternative to the C<bless>
967 builtin operator used to create objects. A function with the specified
968 name should exist, and should accept the same arguments as the builtin.
973 $Data::Dumper::Pair I<or> $I<OBJ>->Pair(I<[NEWVAL]>)
975 Can be set to a string that specifies the separator between hash keys
976 and values. To dump nested hash, array and scalar values to JavaScript,
977 use: C<$Data::Dumper::Pair = ' : ';>. Implementing C<bless> in JavaScript
978 is left as an exercise for the reader.
979 A function with the specified name exists, and accepts the same arguments
982 Default is: C< =E<gt> >.
986 $Data::Dumper::Maxdepth I<or> $I<OBJ>->Maxdepth(I<[NEWVAL]>)
988 Can be set to a positive integer that specifies the depth beyond which
989 which we don't venture into a structure. Has no effect when
990 C<Data::Dumper::Purity> is set. (Useful in debugger when we often don't
991 want to see more than enough). Default is 0, which means there is
996 $Data::Dumper::Useperl I<or> $I<OBJ>->Useperl(I<[NEWVAL]>)
998 Can be set to a boolean value which controls whether the pure Perl
999 implementation of C<Data::Dumper> is used. The C<Data::Dumper> module is
1000 a dual implementation, with almost all functionality written in both
1001 pure Perl and also in XS ('C'). Since the XS version is much faster, it
1002 will always be used if possible. This option lets you override the
1003 default behavior, usually for testing purposes only. Default is 0, which
1004 means the XS implementation will be used if possible.
1008 $Data::Dumper::Sortkeys I<or> $I<OBJ>->Sortkeys(I<[NEWVAL]>)
1010 Can be set to a boolean value to control whether hash keys are dumped in
1011 sorted order. A true value will cause the keys of all hashes to be
1012 dumped in Perl's default sort order. Can also be set to a subroutine
1013 reference which will be called for each hash that is dumped. In this
1014 case C<Data::Dumper> will call the subroutine once for each hash,
1015 passing it the reference of the hash. The purpose of the subroutine is
1016 to return a reference to an array of the keys that will be dumped, in
1017 the order that they should be dumped. Using this feature, you can
1018 control both the order of the keys, and which keys are actually used. In
1019 other words, this subroutine acts as a filter by which you can exclude
1020 certain keys from being dumped. Default is 0, which means that hash keys
1025 $Data::Dumper::Deparse I<or> $I<OBJ>->Deparse(I<[NEWVAL]>)
1027 Can be set to a boolean value to control whether code references are
1028 turned into perl source code. If set to a true value, C<B::Deparse>
1029 will be used to get the source of the code reference. Using this option
1030 will force using the Perl implementation of the dumper, since the fast
1031 XSUB implementation doesn't support it.
1033 Caution : use this option only if you know that your coderefs will be
1034 properly reconstructed by C<B::Deparse>.
1048 Run these code snippets to get a quick feel for the behavior of this
1049 module. When you are through with these examples, you may want to
1050 add or change the various configuration variables described above,
1051 to see their behavior. (See the testsuite in the Data::Dumper
1052 distribution for more examples.)
1058 sub new {bless {'a' => 1, 'b' => sub { return "foo" }}, $_[0]};
1060 package Fuz; # a weird REF-REF-SCALAR object
1061 sub new {bless \($_ = \ 'fu\'z'), $_[0]};
1066 $boo = [ 1, [], "abcd", \*foo,
1067 {1 => 'a', 023 => 'b', 0x45 => 'c'},
1068 \\"p\q\'r", $foo, $fuz];
1074 $bar = eval(Dumper($boo));
1076 print Dumper($boo), Dumper($bar); # pretty print (no array indices)
1078 $Data::Dumper::Terse = 1; # don't output names where feasible
1079 $Data::Dumper::Indent = 0; # turn off all pretty print
1080 print Dumper($boo), "\n";
1082 $Data::Dumper::Indent = 1; # mild pretty print
1085 $Data::Dumper::Indent = 3; # pretty print with array indices
1088 $Data::Dumper::Useqq = 1; # print strings in double quotes
1091 $Data::Dumper::Pair = " : "; # specify hash key/value separator
1096 # recursive structures
1106 print Data::Dumper->Dump([$a,$b,$c], [qw(a b c)]);
1109 $Data::Dumper::Purity = 1; # fill in the holes for eval
1110 print Data::Dumper->Dump([$a, $b], [qw(*a b)]); # print as @a
1111 print Data::Dumper->Dump([$b, $a], [qw(*b a)]); # print as %b
1114 $Data::Dumper::Deepcopy = 1; # avoid cross-refs
1115 print Data::Dumper->Dump([$b, $a], [qw(*b a)]);
1118 $Data::Dumper::Purity = 0; # avoid cross-refs
1119 print Data::Dumper->Dump([$b, $a], [qw(*b a)]);
1131 print Data::Dumper->Dump([$f], [qw(f)]);
1133 $Data::Dumper::Maxdepth = 3; # no deeper than 3 refs down
1134 print Data::Dumper->Dump([$f], [qw(f)]);
1138 # object-oriented usage
1141 $d = Data::Dumper->new([$a,$b], [qw(a b)]);
1142 $d->Seen({'*c' => $c}); # stash a ref without printing it
1145 $d->Reset->Purity(0); # empty the seen cache
1146 print join "----\n", $d->Dump;
1154 sub new { bless { state => 'awake' }, shift }
1157 print STDERR "preparing to sleep\n";
1158 $s->{state} = 'asleep';
1159 return bless $s, 'Foo::ZZZ';
1165 print STDERR "waking up\n";
1166 $s->{state} = 'awake';
1167 return bless $s, 'Foo';
1173 $b = Data::Dumper->new([$a], ['c']);
1174 $b->Freezer('Freeze');
1175 $b->Toaster('Thaw');
1179 print Data::Dumper->Dump([$d], ['d']);
1183 # symbol substitution (useful for recreating CODE refs)
1186 sub foo { print "foo speaking\n" }
1189 $d = Data::Dumper->new([\&other,$bar],['*other','bar']);
1190 $d->Seen({ '*foo' => \&foo });
1195 # sorting and filtering hash keys
1198 $Data::Dumper::Sortkeys = \&my_filter;
1199 my $foo = { map { (ord, "$_$_$_") } 'I'..'Q' };
1200 my $bar = { %$foo };
1201 my $baz = { reverse %$foo };
1202 print Dumper [ $foo, $bar, $baz ];
1206 # return an array ref containing the hash keys to dump
1207 # in the order that you want them to be dumped
1209 # Sort the keys of %$foo in reverse numeric order
1210 $hash eq $foo ? (sort {$b <=> $a} keys %$hash) :
1211 # Only dump the odd number keys of %$bar
1212 $hash eq $bar ? (grep {$_ % 2} keys %$hash) :
1213 # Sort keys in default order for all other hashes
1220 Due to limitations of Perl subroutine call semantics, you cannot pass an
1221 array or hash. Prepend it with a C<\> to pass its reference instead. This
1222 will be remedied in time, now that Perl has subroutine prototypes.
1223 For now, you need to use the extended usage form, and prepend the
1224 name with a C<*> to output it as a hash or array.
1226 C<Data::Dumper> cheats with CODE references. If a code reference is
1227 encountered in the structure being processed (and if you haven't set
1228 the C<Deparse> flag), an anonymous subroutine that
1229 contains the string '"DUMMY"' will be inserted in its place, and a warning
1230 will be printed if C<Purity> is set. You can C<eval> the result, but bear
1231 in mind that the anonymous sub that gets created is just a placeholder.
1232 Someday, perl will have a switch to cache-on-demand the string
1233 representation of a compiled piece of code, I hope. If you have prior
1234 knowledge of all the code refs that your data structures are likely
1235 to have, you can use the C<Seen> method to pre-seed the internal reference
1236 table and make the dumped output point to them, instead. See L</EXAMPLES>
1239 The C<Useqq> and C<Deparse> flags makes Dump() run slower, since the
1240 XSUB implementation does not support them.
1242 SCALAR objects have the weirdest looking C<bless> workaround.
1244 Pure Perl version of C<Data::Dumper> escapes UTF-8 strings correctly
1245 only in Perl 5.8.0 and later.
1249 Starting from Perl 5.8.1 different runs of Perl will have different
1250 ordering of hash keys. The change was done for greater security,
1251 see L<perlsec/"Algorithmic Complexity Attacks">. This means that
1252 different runs of Perl will have different Data::Dumper outputs if
1253 the data contains hashes. If you need to have identical Data::Dumper
1254 outputs from different runs of Perl, use the environment variable
1255 PERL_HASH_SEED, see L<perlrun/PERL_HASH_SEED>. Using this restores
1256 the old (platform-specific) ordering: an even prettier solution might
1257 be to use the C<Sortkeys> filter of Data::Dumper.
1261 Gurusamy Sarathy gsar@activestate.com
1263 Copyright (c) 1996-98 Gurusamy Sarathy. All rights reserved.
1264 This program is free software; you can redistribute it and/or
1265 modify it under the same terms as Perl itself.
1269 Version 2.121 (Aug 24 2003)