4 # convert perl data structures into perl syntax suitable for both printing
7 # Documentation at the __END__
12 $VERSION = '2.121_01';
25 @EXPORT_OK = qw(DumperX);
27 XSLoader::load 'Data::Dumper';
29 # module vars and their defaults
30 $Indent = 2 unless defined $Indent;
31 $Purity = 0 unless defined $Purity;
32 $Pad = "" unless defined $Pad;
33 $Varname = "VAR" unless defined $Varname;
34 $Useqq = 0 unless defined $Useqq;
35 $Terse = 0 unless defined $Terse;
36 $Freezer = "" unless defined $Freezer;
37 $Toaster = "" unless defined $Toaster;
38 $Deepcopy = 0 unless defined $Deepcopy;
39 $Quotekeys = 1 unless defined $Quotekeys;
40 $Bless = "bless" unless defined $Bless;
41 #$Expdepth = 0 unless defined $Expdepth;
42 $Maxdepth = 0 unless defined $Maxdepth;
43 $Pair = ' => ' unless defined $Pair;
44 $Useperl = 0 unless defined $Useperl;
45 $Sortkeys = 0 unless defined $Sortkeys;
46 $Deparse = 0 unless defined $Deparse;
49 # expects an arrayref of values to be dumped.
50 # can optionally pass an arrayref of names for the values.
51 # names must have leading $ sign stripped. begin the name with *
52 # to cause output of arrays and hashes rather than refs.
57 croak "Usage: PACKAGE->new(ARRAYREF, [ARRAYREF])"
58 unless (defined($v) && (ref($v) eq 'ARRAY'));
59 $n = [] unless (defined($n) && (ref($v) eq 'ARRAY'));
62 level => 0, # current recursive depth
63 indent => $Indent, # various styles of indenting
64 pad => $Pad, # all lines prefixed by this string
65 xpad => "", # padding-per-level
66 apad => "", # added padding for hash keys n such
67 sep => "", # list separator
68 pair => $Pair, # hash key/value separator: defaults to ' => '
69 seen => {}, # local (nested) refs (id => [name, val])
70 todump => $v, # values to dump []
71 names => $n, # optional names for values []
72 varname => $Varname, # prefix to use for tagging nameless ones
73 purity => $Purity, # degree to which output is evalable
74 useqq => $Useqq, # use "" for strings (backslashitis ensues)
75 terse => $Terse, # avoid name output (where feasible)
76 freezer => $Freezer, # name of Freezer method for objects
77 toaster => $Toaster, # name of method to revive objects
78 deepcopy => $Deepcopy, # dont cross-ref, except to stop recursion
79 quotekeys => $Quotekeys, # quote hash keys
80 'bless' => $Bless, # keyword to use for "bless"
81 # expdepth => $Expdepth, # cutoff depth for explicit dumping
82 maxdepth => $Maxdepth, # depth beyond which we give up
83 useperl => $Useperl, # use the pure Perl implementation
84 sortkeys => $Sortkeys, # flag or filter for sorting hash keys
85 deparse => $Deparse, # use B::Deparse for coderefs
96 # add-to or query the table of already seen references
100 if (defined($g) && (ref($g) eq 'HASH')) {
102 while (($k, $v) = each %$g) {
103 if (defined $v and ref $v) {
104 ($id) = (overload::StrVal($v) =~ /\((.*)\)$/);
105 if ($k =~ /^[*](.*)$/) {
106 $k = (ref $v eq 'ARRAY') ? ( "\\\@" . $1 ) :
107 (ref $v eq 'HASH') ? ( "\\\%" . $1 ) :
108 (ref $v eq 'CODE') ? ( "\\\&" . $1 ) :
111 elsif ($k !~ /^\$/) {
114 $s->{seen}{$id} = [$k, $v];
117 carp "Only refs supported, ignoring non-ref item \$$k";
123 return map { @$_ } values %{$s->{seen}};
128 # set or query the values to be dumped
132 if (defined($v) && (ref($v) eq 'ARRAY')) {
133 $s->{todump} = [@$v]; # make a copy
137 return @{$s->{todump}};
142 # set or query the names of the values to be dumped
146 if (defined($n) && (ref($n) eq 'ARRAY')) {
147 $s->{names} = [@$n]; # make a copy
151 return @{$s->{names}};
159 unless $Data::Dumper::Useperl || (ref($_[0]) && $_[0]->{useperl}) ||
160 $Data::Dumper::Useqq || (ref($_[0]) && $_[0]->{useqq}) ||
161 $Data::Dumper::Deparse || (ref($_[0]) && $_[0]->{deparse});
166 # dump the refs in the current dumper object.
167 # expects same args as new() if called via package name.
171 my(@out, $val, $name);
175 $s = $s->new(@_) unless ref $s;
177 for $val (@{$s->{todump}}) {
180 $name = $s->{names}[$i++];
182 if ($name =~ /^[*](.*)$/) {
184 $name = (ref $val eq 'ARRAY') ? ( "\@" . $1 ) :
185 (ref $val eq 'HASH') ? ( "\%" . $1 ) :
186 (ref $val eq 'CODE') ? ( "\*" . $1 ) :
193 elsif ($name !~ /^\$/) {
194 $name = "\$" . $name;
198 $name = "\$" . $s->{varname} . $i;
203 local($s->{apad}) = $s->{apad};
204 $s->{apad} .= ' ' x (length($name) + 3) if $s->{indent} >= 2;
205 $valstr = $s->_dump($val, $name);
208 $valstr = "$name = " . $valstr . ';' if @post or !$s->{terse};
209 $out .= $s->{pad} . $valstr . $s->{sep};
210 $out .= $s->{pad} . join(';' . $s->{sep} . $s->{pad}, @post)
211 . ';' . $s->{sep} if @post;
215 return wantarray ? @out : join('', @out);
219 # twist, toil and turn;
220 # and recurse, of course.
221 # sometimes sordidly;
222 # and curse if no recourse.
225 my($s, $val, $name) = @_;
227 my($out, $realpack, $realtype, $type, $ipad, $id, $blesspad);
234 # prep it, if it looks like an object
235 if (my $freezer = $s->{freezer}) {
236 $val->$freezer() if UNIVERSAL::can($val, $freezer);
239 ($realpack, $realtype, $id) =
240 (overload::StrVal($val) =~ /^(?:(.*)\=)?([^=]*)\(([^\(]*)\)$/);
242 # if it has a name, we need to either look it up, or keep a tab
243 # on it so we know when we hit it later
244 if (defined($name) and length($name)) {
245 # keep a tab on it so that we dont fall into recursive pit
246 if (exists $s->{seen}{$id}) {
247 # if ($s->{expdepth} < $s->{level}) {
248 if ($s->{purity} and $s->{level} > 0) {
249 $out = ($realtype eq 'HASH') ? '{}' :
250 ($realtype eq 'ARRAY') ? '[]' :
252 push @post, $name . " = " . $s->{seen}{$id}[0];
255 $out = $s->{seen}{$id}[0];
256 if ($name =~ /^([\@\%])/) {
258 if ($out =~ /^\\$start/) {
259 $out = substr($out, 1);
262 $out = $start . '{' . $out . '}';
271 $s->{seen}{$id} = [ (($name =~ /^[@%]/) ? ('\\' . $name ) :
272 ($realtype eq 'CODE' and
273 $name =~ /^[*](.*)$/) ? ('\\&' . $1 ) :
279 if ($realpack and $realpack eq 'Regexp') {
285 # If purity is not set and maxdepth is set, then check depth:
286 # if we have reached maximum depth, return the string
287 # representation of the thing we are currently examining
288 # at this depth (i.e., 'Foo=ARRAY(0xdeadbeef)').
290 and $s->{maxdepth} > 0
291 and $s->{level} >= $s->{maxdepth})
296 # we have a blessed ref
298 $out = $s->{'bless'} . '( ';
299 $blesspad = $s->{apad};
300 $s->{apad} .= ' ' if ($s->{indent} >= 2);
304 $ipad = $s->{xpad} x $s->{level};
306 if ($realtype eq 'SCALAR' || $realtype eq 'REF') {
308 $out .= 'do{\\(my $o = ' . $s->_dump($$val, "\${$name}") . ')}';
311 $out .= '\\' . $s->_dump($$val, "\${$name}");
314 elsif ($realtype eq 'GLOB') {
315 $out .= '\\' . $s->_dump($$val, "*{$name}");
317 elsif ($realtype eq 'ARRAY') {
318 my($v, $pad, $mname);
320 $out .= ($name =~ /^\@/) ? '(' : '[';
321 $pad = $s->{sep} . $s->{pad} . $s->{apad};
322 ($name =~ /^\@(.*)$/) ? ($mname = "\$" . $1) :
323 # omit -> if $foo->[0]->{bar}, but not ${$foo->[0]}->{bar}
324 ($name =~ /^\\?[\%\@\*\$][^{].*[]}]$/) ? ($mname = $name) :
325 ($mname = $name . '->');
326 $mname .= '->' if $mname =~ /^\*.+\{[A-Z]+\}$/;
328 $sname = $mname . '[' . $i . ']';
329 $out .= $pad . $ipad . '#' . $i if $s->{indent} >= 3;
330 $out .= $pad . $ipad . $s->_dump($v, $sname);
331 $out .= "," if $i++ < $#$val;
333 $out .= $pad . ($s->{xpad} x ($s->{level} - 1)) if $i;
334 $out .= ($name =~ /^\@/) ? ')' : ']';
336 elsif ($realtype eq 'HASH') {
337 my($k, $v, $pad, $lpad, $mname, $pair);
338 $out .= ($name =~ /^\%/) ? '(' : '{';
339 $pad = $s->{sep} . $s->{pad} . $s->{apad};
342 ($name =~ /^\%(.*)$/) ? ($mname = "\$" . $1) :
343 # omit -> if $foo->[0]->{bar}, but not ${$foo->[0]}->{bar}
344 ($name =~ /^\\?[\%\@\*\$][^{].*[]}]$/) ? ($mname = $name) :
345 ($mname = $name . '->');
346 $mname .= '->' if $mname =~ /^\*.+\{[A-Z]+\}$/;
347 my ($sortkeys, $keys, $key) = ("$s->{sortkeys}");
349 if (ref($s->{sortkeys}) eq 'CODE') {
350 $keys = $s->{sortkeys}($val);
351 unless (ref($keys) eq 'ARRAY') {
352 carp "Sortkeys subroutine did not return ARRAYREF";
357 $keys = [ sort keys %$val ];
360 while (($k, $v) = ! $sortkeys ? (each %$val) :
361 @$keys ? ($key = shift(@$keys), $val->{$key}) :
364 my $nk = $s->_dump($k, "");
365 $nk = $1 if !$s->{quotekeys} and $nk =~ /^[\"\']([A-Za-z_]\w*)[\"\']$/;
366 $sname = $mname . '{' . $nk . '}';
367 $out .= $pad . $ipad . $nk . $pair;
369 # temporarily alter apad
370 $s->{apad} .= (" " x (length($nk) + 4)) if $s->{indent} >= 2;
371 $out .= $s->_dump($val->{$k}, $sname) . ",";
372 $s->{apad} = $lpad if $s->{indent} >= 2;
374 if (substr($out, -1) eq ',') {
376 $out .= $pad . ($s->{xpad} x ($s->{level} - 1));
378 $out .= ($name =~ /^\%/) ? ')' : '}';
380 elsif ($realtype eq 'CODE') {
383 my $sub = 'sub ' . (B::Deparse->new)->coderef2text($val);
384 $pad = $s->{sep} . $s->{pad} . $s->{apad} . $s->{xpad} x ($s->{level} - 1);
385 $sub =~ s/\n/$pad/gse;
388 $out .= 'sub { "DUMMY" }';
389 carp "Encountered CODE ref, using dummy placeholder" if $s->{purity};
393 croak "Can\'t handle $realtype type.";
396 if ($realpack) { # we have a blessed ref
397 $out .= ', \'' . $realpack . '\'' . ' )';
398 $out .= '->' . $s->{toaster} . '()' if $s->{toaster} ne '';
399 $s->{apad} = $blesspad;
404 else { # simple scalar
407 # first, catalog the scalar
409 ($id) = ("$ref" =~ /\(([^\(]*)\)$/);
410 if (exists $s->{seen}{$id}) {
411 if ($s->{seen}{$id}[2]) {
412 $out = $s->{seen}{$id}[0];
418 #warn "[>\\$name]\n";
419 $s->{seen}{$id} = ["\\$name", $ref];
422 if (ref($ref) eq 'GLOB' or "$ref" =~ /=GLOB\([^()]+\)$/) { # glob
423 my $name = substr($val, 1);
424 if ($name =~ /^[A-Za-z_][\w:]*$/) {
425 $name =~ s/^main::/::/;
429 $sname = $s->_dump($name, "");
430 $sname = '{' . $sname . '}';
434 local ($s->{level}) = 0;
435 for $k (qw(SCALAR ARRAY HASH)) {
436 my $gval = *$val{$k};
437 next unless defined $gval;
438 next if $k eq "SCALAR" && ! defined $$gval; # always there
440 # _dump can push into @post, so we hold our place using $postlen
441 my $postlen = scalar @post;
442 $post[$postlen] = "\*$sname = ";
443 local ($s->{apad}) = " " x length($post[$postlen]) if $s->{indent} >= 2;
444 $post[$postlen] .= $s->_dump($gval, "\*$sname\{$k\}");
447 $out .= '*' . $sname;
449 elsif (!defined($val)) {
452 elsif ($val =~ /^(?:0|-?[1-9]\d{0,8})\z/) { # safe decimal number
456 if ($s->{useqq} or $val =~ tr/\0-\377//c) {
457 # Fall back to qq if there's unicode
458 $out .= qquote($val, $s->{useqq});
461 $val =~ s/([\\\'])/\\$1/g;
462 $out .= '\'' . $val . '\'';
467 # if we made it this far, $id was added to seen list at current
468 # level, so remove it to get deep copies
469 if ($s->{deepcopy}) {
470 delete($s->{seen}{$id});
473 $s->{seen}{$id}[2] = 1;
480 # non-OO style of earlier version
483 return Data::Dumper->Dump([@_]);
488 return Data::Dumper->Dumpxs([@_], []);
491 sub Dumpf { return Data::Dumper->Dump(@_) }
493 sub Dumpp { print Data::Dumper->Dump(@_) }
496 # reset the "seen" cache
525 defined($v) ? (($s->{pair} = $v), return $s) : $s->{pair};
530 defined($v) ? (($s->{pad} = $v), return $s) : $s->{pad};
535 defined($v) ? (($s->{varname} = $v), return $s) : $s->{varname};
540 defined($v) ? (($s->{purity} = $v), return $s) : $s->{purity};
545 defined($v) ? (($s->{useqq} = $v), return $s) : $s->{useqq};
550 defined($v) ? (($s->{terse} = $v), return $s) : $s->{terse};
555 defined($v) ? (($s->{freezer} = $v), return $s) : $s->{freezer};
560 defined($v) ? (($s->{toaster} = $v), return $s) : $s->{toaster};
565 defined($v) ? (($s->{deepcopy} = $v), return $s) : $s->{deepcopy};
570 defined($v) ? (($s->{quotekeys} = $v), return $s) : $s->{quotekeys};
575 defined($v) ? (($s->{'bless'} = $v), return $s) : $s->{'bless'};
580 defined($v) ? (($s->{'maxdepth'} = $v), return $s) : $s->{'maxdepth'};
585 defined($v) ? (($s->{'useperl'} = $v), return $s) : $s->{'useperl'};
590 defined($v) ? (($s->{'sortkeys'} = $v), return $s) : $s->{'sortkeys'};
595 defined($v) ? (($s->{'deparse'} = $v), return $s) : $s->{'deparse'};
598 # used by qquote below
609 # put a string value in double quotes
612 s/([\\\"\@\$])/\\$1/g;
613 my $bytes; { use bytes; $bytes = length }
614 s/([^\x00-\x7f])/'\x{'.sprintf("%x",ord($1)).'}'/ge if $bytes > length;
615 return qq("$_") unless
616 /[^ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~]/; # fast exit
618 my $high = shift || "";
619 s/([\a\b\t\n\f\r\e])/$esc{$1}/g;
621 if (ord('^')==94) { # ascii
622 # no need for 3 digits in escape for these
623 s/([\0-\037])(?!\d)/'\\'.sprintf('%o',ord($1))/eg;
624 s/([\0-\037\177])/'\\'.sprintf('%03o',ord($1))/eg;
625 # all but last branch below not supported --BEHAVIOR SUBJECT TO CHANGE--
626 if ($high eq "iso8859") {
627 s/([\200-\240])/'\\'.sprintf('%o',ord($1))/eg;
628 } elsif ($high eq "utf8") {
630 # $str =~ s/([^\040-\176])/sprintf "\\x{%04x}", ord($1)/ge;
631 } elsif ($high eq "8bit") {
634 s/([\200-\377])/'\\'.sprintf('%03o',ord($1))/eg;
635 s/([^\040-\176])/sprintf "\\x{%04x}", ord($1)/ge;
639 s{([^ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~])(?!\d)}
640 {my $v = ord($1); '\\'.sprintf(($v <= 037 ? '%o' : '%03o'), $v)}eg;
641 s{([^ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~])}
642 {'\\'.sprintf('%03o',ord($1))}eg;
648 # helper sub to sort hash keys in Perl < 5.8.0 where we don't have
649 # access to sortsv() from XS
650 sub _sortkeys { [ sort keys %{$_[0]} ] }
657 Data::Dumper - stringified perl data structures, suitable for both printing and C<eval>
663 # simple procedural interface
664 print Dumper($foo, $bar);
666 # extended usage with names
667 print Data::Dumper->Dump([$foo, $bar], [qw(foo *ary)]);
669 # configuration variables
671 local $Data::Dumper::Purity = 1;
672 eval Data::Dumper->Dump([$foo, $bar], [qw(foo *ary)]);
676 $d = Data::Dumper->new([$foo, $bar], [qw(foo *ary)]);
680 $d->Purity(1)->Terse(1)->Deepcopy(1);
686 Given a list of scalars or reference variables, writes out their contents in
687 perl syntax. The references can also be objects. The contents of each
688 variable is output in a single Perl statement. Handles self-referential
689 structures correctly.
691 The return value can be C<eval>ed to get back an identical copy of the
692 original reference structure.
694 Any references that are the same as one of those passed in will be named
695 C<$VAR>I<n> (where I<n> is a numeric suffix), and other duplicate references
696 to substructures within C<$VAR>I<n> will be appropriately labeled using arrow
697 notation. You can specify names for individual values to be dumped if you
698 use the C<Dump()> method, or you can change the default C<$VAR> prefix to
699 something else. See C<$Data::Dumper::Varname> and C<$Data::Dumper::Terse>
702 The default output of self-referential structures can be C<eval>ed, but the
703 nested references to C<$VAR>I<n> will be undefined, since a recursive
704 structure cannot be constructed using one Perl statement. You should set the
705 C<Purity> flag to 1 to get additional statements that will correctly fill in
708 In the extended usage form, the references to be dumped can be given
709 user-specified names. If a name begins with a C<*>, the output will
710 describe the dereferenced type of the supplied reference for hashes and
711 arrays, and coderefs. Output of names will be avoided where possible if
712 the C<Terse> flag is set.
714 In many cases, methods that are used to set the internal state of the
715 object will return the object itself, so method calls can be conveniently
718 Several styles of output are possible, all controlled by setting
719 the C<Indent> flag. See L<Configuration Variables or Methods> below
727 =item I<PACKAGE>->new(I<ARRAYREF [>, I<ARRAYREF]>)
729 Returns a newly created C<Data::Dumper> object. The first argument is an
730 anonymous array of values to be dumped. The optional second argument is an
731 anonymous array of names for the values. The names need not have a leading
732 C<$> sign, and must be comprised of alphanumeric characters. You can begin
733 a name with a C<*> to specify that the dereferenced type must be dumped
734 instead of the reference itself, for ARRAY and HASH references.
736 The prefix specified by C<$Data::Dumper::Varname> will be used with a
737 numeric suffix if the name for a value is undefined.
739 Data::Dumper will catalog all references encountered while dumping the
740 values. Cross-references (in the form of names of substructures in perl
741 syntax) will be inserted at all possible points, preserving any structural
742 interdependencies in the original set of values. Structure traversal is
743 depth-first, and proceeds in order from the first supplied value to
746 =item I<$OBJ>->Dump I<or> I<PACKAGE>->Dump(I<ARRAYREF [>, I<ARRAYREF]>)
748 Returns the stringified form of the values stored in the object (preserving
749 the order in which they were supplied to C<new>), subject to the
750 configuration options below. In a list context, it returns a list
751 of strings corresponding to the supplied values.
753 The second form, for convenience, simply calls the C<new> method on its
754 arguments before dumping the object immediately.
756 =item I<$OBJ>->Seen(I<[HASHREF]>)
758 Queries or adds to the internal table of already encountered references.
759 You must use C<Reset> to explicitly clear the table if needed. Such
760 references are not dumped; instead, their names are inserted wherever they
761 are encountered subsequently. This is useful especially for properly
762 dumping subroutine references.
764 Expects an anonymous hash of name => value pairs. Same rules apply for names
765 as in C<new>. If no argument is supplied, will return the "seen" list of
766 name => value pairs, in a list context. Otherwise, returns the object
769 =item I<$OBJ>->Values(I<[ARRAYREF]>)
771 Queries or replaces the internal array of values that will be dumped.
772 When called without arguments, returns the values. Otherwise, returns the
775 =item I<$OBJ>->Names(I<[ARRAYREF]>)
777 Queries or replaces the internal array of user supplied names for the values
778 that will be dumped. When called without arguments, returns the names.
779 Otherwise, returns the object itself.
783 Clears the internal table of "seen" references and returns the object
792 =item Dumper(I<LIST>)
794 Returns the stringified form of the values in the list, subject to the
795 configuration options below. The values will be named C<$VAR>I<n> in the
796 output, where I<n> is a numeric suffix. Will return a list of strings
801 =head2 Configuration Variables or Methods
803 Several configuration variables can be used to control the kind of output
804 generated when using the procedural interface. These variables are usually
805 C<local>ized in a block so that other parts of the code are not affected by
808 These variables determine the default state of the object created by calling
809 the C<new> method, but cannot be used to alter the state of the object
810 thereafter. The equivalent method names should be used instead to query
811 or set the internal state of the object.
813 The method forms return the object itself when called with arguments,
814 so that they can be chained together nicely.
820 $Data::Dumper::Indent I<or> I<$OBJ>->Indent(I<[NEWVAL]>)
822 Controls the style of indentation. It can be set to 0, 1, 2 or 3. Style 0
823 spews output without any newlines, indentation, or spaces between list
824 items. It is the most compact format possible that can still be called
825 valid perl. Style 1 outputs a readable form with newlines but no fancy
826 indentation (each level in the structure is simply indented by a fixed
827 amount of whitespace). Style 2 (the default) outputs a very readable form
828 which takes into account the length of hash keys (so the hash value lines
829 up). Style 3 is like style 2, but also annotates the elements of arrays
830 with their index (but the comment is on its own line, so array output
831 consumes twice the number of lines). Style 2 is the default.
835 $Data::Dumper::Purity I<or> I<$OBJ>->Purity(I<[NEWVAL]>)
837 Controls the degree to which the output can be C<eval>ed to recreate the
838 supplied reference structures. Setting it to 1 will output additional perl
839 statements that will correctly recreate nested references. The default is
844 $Data::Dumper::Pad I<or> I<$OBJ>->Pad(I<[NEWVAL]>)
846 Specifies the string that will be prefixed to every line of the output.
847 Empty string by default.
851 $Data::Dumper::Varname I<or> I<$OBJ>->Varname(I<[NEWVAL]>)
853 Contains the prefix to use for tagging variable names in the output. The
858 $Data::Dumper::Useqq I<or> I<$OBJ>->Useqq(I<[NEWVAL]>)
860 When set, enables the use of double quotes for representing string values.
861 Whitespace other than space will be represented as C<[\n\t\r]>, "unsafe"
862 characters will be backslashed, and unprintable characters will be output as
863 quoted octal integers. Since setting this variable imposes a performance
864 penalty, the default is 0. C<Dump()> will run slower if this flag is set,
865 since the fast XSUB implementation doesn't support it yet.
869 $Data::Dumper::Terse I<or> I<$OBJ>->Terse(I<[NEWVAL]>)
871 When set, Data::Dumper will emit single, non-self-referential values as
872 atoms/terms rather than statements. This means that the C<$VAR>I<n> names
873 will be avoided where possible, but be advised that such output may not
874 always be parseable by C<eval>.
878 $Data::Dumper::Freezer I<or> $I<OBJ>->Freezer(I<[NEWVAL]>)
880 Can be set to a method name, or to an empty string to disable the feature.
881 Data::Dumper will invoke that method via the object before attempting to
882 stringify it. This method can alter the contents of the object (if, for
883 instance, it contains data allocated from C), and even rebless it in a
884 different package. The client is responsible for making sure the specified
885 method can be called via the object, and that the object ends up containing
886 only perl data types after the method has been called. Defaults to an empty
891 $Data::Dumper::Toaster I<or> $I<OBJ>->Toaster(I<[NEWVAL]>)
893 Can be set to a method name, or to an empty string to disable the feature.
894 Data::Dumper will emit a method call for any objects that are to be dumped
895 using the syntax C<bless(DATA, CLASS)-E<gt>METHOD()>. Note that this means that
896 the method specified will have to perform any modifications required on the
897 object (like creating new state within it, and/or reblessing it in a
898 different package) and then return it. The client is responsible for making
899 sure the method can be called via the object, and that it returns a valid
900 object. Defaults to an empty string.
904 $Data::Dumper::Deepcopy I<or> $I<OBJ>->Deepcopy(I<[NEWVAL]>)
906 Can be set to a boolean value to enable deep copies of structures.
907 Cross-referencing will then only be done when absolutely essential
908 (i.e., to break reference cycles). Default is 0.
912 $Data::Dumper::Quotekeys I<or> $I<OBJ>->Quotekeys(I<[NEWVAL]>)
914 Can be set to a boolean value to control whether hash keys are quoted.
915 A false value will avoid quoting hash keys when it looks like a simple
916 string. Default is 1, which will always enclose hash keys in quotes.
920 $Data::Dumper::Bless I<or> $I<OBJ>->Bless(I<[NEWVAL]>)
922 Can be set to a string that specifies an alternative to the C<bless>
923 builtin operator used to create objects. A function with the specified
924 name should exist, and should accept the same arguments as the builtin.
929 $Data::Dumper::Pair I<or> $I<OBJ>->Pair(I<[NEWVAL]>)
931 Can be set to a string that specifies the separator between hash keys
932 and values. To dump nested hash, array and scalar values to JavaScript,
933 use: C<$Data::Dumper::Pair = ' : ';>. Implementing C<bless> in JavaScript
934 is left as an exercise for the reader.
935 A function with the specified name exists, and accepts the same arguments
938 Default is: C< =E<gt> >.
942 $Data::Dumper::Maxdepth I<or> $I<OBJ>->Maxdepth(I<[NEWVAL]>)
944 Can be set to a positive integer that specifies the depth beyond which
945 which we don't venture into a structure. Has no effect when
946 C<Data::Dumper::Purity> is set. (Useful in debugger when we often don't
947 want to see more than enough). Default is 0, which means there is
952 $Data::Dumper::Useperl I<or> $I<OBJ>->Useperl(I<[NEWVAL]>)
954 Can be set to a boolean value which controls whether the pure Perl
955 implementation of C<Data::Dumper> is used. The C<Data::Dumper> module is
956 a dual implementation, with almost all functionality written in both
957 pure Perl and also in XS ('C'). Since the XS version is much faster, it
958 will always be used if possible. This option lets you override the
959 default behavior, usually for testing purposes only. Default is 0, which
960 means the XS implementation will be used if possible.
964 $Data::Dumper::Sortkeys I<or> $I<OBJ>->Sortkeys(I<[NEWVAL]>)
966 Can be set to a boolean value to control whether hash keys are dumped in
967 sorted order. A true value will cause the keys of all hashes to be
968 dumped in Perl's default sort order. Can also be set to a subroutine
969 reference which will be called for each hash that is dumped. In this
970 case C<Data::Dumper> will call the subroutine once for each hash,
971 passing it the reference of the hash. The purpose of the subroutine is
972 to return a reference to an array of the keys that will be dumped, in
973 the order that they should be dumped. Using this feature, you can
974 control both the order of the keys, and which keys are actually used. In
975 other words, this subroutine acts as a filter by which you can exclude
976 certain keys from being dumped. Default is 0, which means that hash keys
981 $Data::Dumper::Deparse I<or> $I<OBJ>->Deparse(I<[NEWVAL]>)
983 Can be set to a boolean value to control whether code references are
984 turned into perl source code. If set to a true value, C<B::Deparse>
985 will be used to get the source of the code reference. Using this option
986 will force using the Perl implementation of the dumper, since the fast
987 XSUB implementation doesn't support it.
989 Caution : use this option only if you know that your coderefs will be
990 properly reconstructed by C<B::Deparse>.
1004 Run these code snippets to get a quick feel for the behavior of this
1005 module. When you are through with these examples, you may want to
1006 add or change the various configuration variables described above,
1007 to see their behavior. (See the testsuite in the Data::Dumper
1008 distribution for more examples.)
1014 sub new {bless {'a' => 1, 'b' => sub { return "foo" }}, $_[0]};
1016 package Fuz; # a weird REF-REF-SCALAR object
1017 sub new {bless \($_ = \ 'fu\'z'), $_[0]};
1022 $boo = [ 1, [], "abcd", \*foo,
1023 {1 => 'a', 023 => 'b', 0x45 => 'c'},
1024 \\"p\q\'r", $foo, $fuz];
1030 $bar = eval(Dumper($boo));
1032 print Dumper($boo), Dumper($bar); # pretty print (no array indices)
1034 $Data::Dumper::Terse = 1; # don't output names where feasible
1035 $Data::Dumper::Indent = 0; # turn off all pretty print
1036 print Dumper($boo), "\n";
1038 $Data::Dumper::Indent = 1; # mild pretty print
1041 $Data::Dumper::Indent = 3; # pretty print with array indices
1044 $Data::Dumper::Useqq = 1; # print strings in double quotes
1047 $Data::Dumper::Pair = " : "; # specify hash key/value separator
1052 # recursive structures
1062 print Data::Dumper->Dump([$a,$b,$c], [qw(a b c)]);
1065 $Data::Dumper::Purity = 1; # fill in the holes for eval
1066 print Data::Dumper->Dump([$a, $b], [qw(*a b)]); # print as @a
1067 print Data::Dumper->Dump([$b, $a], [qw(*b a)]); # print as %b
1070 $Data::Dumper::Deepcopy = 1; # avoid cross-refs
1071 print Data::Dumper->Dump([$b, $a], [qw(*b a)]);
1074 $Data::Dumper::Purity = 0; # avoid cross-refs
1075 print Data::Dumper->Dump([$b, $a], [qw(*b a)]);
1087 print Data::Dumper->Dump([$f], [qw(f)]);
1089 $Data::Dumper::Maxdepth = 3; # no deeper than 3 refs down
1090 print Data::Dumper->Dump([$f], [qw(f)]);
1094 # object-oriented usage
1097 $d = Data::Dumper->new([$a,$b], [qw(a b)]);
1098 $d->Seen({'*c' => $c}); # stash a ref without printing it
1101 $d->Reset->Purity(0); # empty the seen cache
1102 print join "----\n", $d->Dump;
1110 sub new { bless { state => 'awake' }, shift }
1113 print STDERR "preparing to sleep\n";
1114 $s->{state} = 'asleep';
1115 return bless $s, 'Foo::ZZZ';
1121 print STDERR "waking up\n";
1122 $s->{state} = 'awake';
1123 return bless $s, 'Foo';
1129 $b = Data::Dumper->new([$a], ['c']);
1130 $b->Freezer('Freeze');
1131 $b->Toaster('Thaw');
1135 print Data::Dumper->Dump([$d], ['d']);
1139 # symbol substitution (useful for recreating CODE refs)
1142 sub foo { print "foo speaking\n" }
1145 $d = Data::Dumper->new([\&other,$bar],['*other','bar']);
1146 $d->Seen({ '*foo' => \&foo });
1151 # sorting and filtering hash keys
1154 $Data::Dumper::Sortkeys = \&my_filter;
1155 my $foo = { map { (ord, "$_$_$_") } 'I'..'Q' };
1156 my $bar = { %$foo };
1157 my $baz = { reverse %$foo };
1158 print Dumper [ $foo, $bar, $baz ];
1162 # return an array ref containing the hash keys to dump
1163 # in the order that you want them to be dumped
1165 # Sort the keys of %$foo in reverse numeric order
1166 $hash eq $foo ? (sort {$b <=> $a} keys %$hash) :
1167 # Only dump the odd number keys of %$bar
1168 $hash eq $bar ? (grep {$_ % 2} keys %$hash) :
1169 # Sort keys in default order for all other hashes
1176 Due to limitations of Perl subroutine call semantics, you cannot pass an
1177 array or hash. Prepend it with a C<\> to pass its reference instead. This
1178 will be remedied in time, now that Perl has subroutine prototypes.
1179 For now, you need to use the extended usage form, and prepend the
1180 name with a C<*> to output it as a hash or array.
1182 C<Data::Dumper> cheats with CODE references. If a code reference is
1183 encountered in the structure being processed (and if you haven't set
1184 the C<Deparse> flag), an anonymous subroutine that
1185 contains the string '"DUMMY"' will be inserted in its place, and a warning
1186 will be printed if C<Purity> is set. You can C<eval> the result, but bear
1187 in mind that the anonymous sub that gets created is just a placeholder.
1188 Someday, perl will have a switch to cache-on-demand the string
1189 representation of a compiled piece of code, I hope. If you have prior
1190 knowledge of all the code refs that your data structures are likely
1191 to have, you can use the C<Seen> method to pre-seed the internal reference
1192 table and make the dumped output point to them, instead. See L<EXAMPLES>
1195 The C<Useqq> and C<Deparse> flags makes Dump() run slower, since the
1196 XSUB implementation does not support them.
1198 SCALAR objects have the weirdest looking C<bless> workaround.
1200 Pure Perl version of C<Data::Dumper> escapes UTF-8 strings correctly
1201 only in Perl 5.8.0 and later.
1205 Starting from Perl 5.8.1 different runs of Perl will have different
1206 ordering of hash keys. The change was done for greater security,
1207 see L<perlsec/"Algorithmic Complexity Attacks">. This means that
1208 different runs of Perl will have different Data::Dumper outputs if
1209 the data contains hashes. If you need to have identical Data::Dumper
1210 outputs from different runs of Perl, use the environment variable
1211 PERL_HASH_SEED, see L<perlrun/PERL_HASH_SEED>. Using this restores
1212 the old (platform-specific) ordering: an even prettier solution might
1213 be to use the C<Sortkeys> filter of Data::Dumper.
1217 Gurusamy Sarathy gsar@activestate.com
1219 Copyright (c) 1996-98 Gurusamy Sarathy. All rights reserved.
1220 This program is free software; you can redistribute it and/or
1221 modify it under the same terms as Perl itself.
1225 Version 2.121 (Aug 24 2003)