4 # convert perl data structures into perl syntax suitable for both printing
7 # Documentation at the __END__
12 $VERSION = '2.121_03';
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 # Call the freezer method if it's specified and the object has the
235 # method. Trap errors and warn() instead of die()ing, like the XS
237 my $freezer = $s->{freezer};
238 if ($freezer and UNIVERSAL::can($val, $freezer)) {
239 eval { $val->$freezer() };
240 warn "WARNING(Freezer method call failed): $@" if $@;
243 ($realpack, $realtype, $id) =
244 (overload::StrVal($val) =~ /^(?:(.*)\=)?([^=]*)\(([^\(]*)\)$/);
246 # if it has a name, we need to either look it up, or keep a tab
247 # on it so we know when we hit it later
248 if (defined($name) and length($name)) {
249 # keep a tab on it so that we dont fall into recursive pit
250 if (exists $s->{seen}{$id}) {
251 # if ($s->{expdepth} < $s->{level}) {
252 if ($s->{purity} and $s->{level} > 0) {
253 $out = ($realtype eq 'HASH') ? '{}' :
254 ($realtype eq 'ARRAY') ? '[]' :
256 push @post, $name . " = " . $s->{seen}{$id}[0];
259 $out = $s->{seen}{$id}[0];
260 if ($name =~ /^([\@\%])/) {
262 if ($out =~ /^\\$start/) {
263 $out = substr($out, 1);
266 $out = $start . '{' . $out . '}';
275 $s->{seen}{$id} = [ (($name =~ /^[@%]/) ? ('\\' . $name ) :
276 ($realtype eq 'CODE' and
277 $name =~ /^[*](.*)$/) ? ('\\&' . $1 ) :
283 if ($realpack and $realpack eq 'Regexp') {
289 # If purity is not set and maxdepth is set, then check depth:
290 # if we have reached maximum depth, return the string
291 # representation of the thing we are currently examining
292 # at this depth (i.e., 'Foo=ARRAY(0xdeadbeef)').
294 and $s->{maxdepth} > 0
295 and $s->{level} >= $s->{maxdepth})
300 # we have a blessed ref
302 $out = $s->{'bless'} . '( ';
303 $blesspad = $s->{apad};
304 $s->{apad} .= ' ' if ($s->{indent} >= 2);
308 $ipad = $s->{xpad} x $s->{level};
310 if ($realtype eq 'SCALAR' || $realtype eq 'REF') {
312 $out .= 'do{\\(my $o = ' . $s->_dump($$val, "\${$name}") . ')}';
315 $out .= '\\' . $s->_dump($$val, "\${$name}");
318 elsif ($realtype eq 'GLOB') {
319 $out .= '\\' . $s->_dump($$val, "*{$name}");
321 elsif ($realtype eq 'ARRAY') {
322 my($v, $pad, $mname);
324 $out .= ($name =~ /^\@/) ? '(' : '[';
325 $pad = $s->{sep} . $s->{pad} . $s->{apad};
326 ($name =~ /^\@(.*)$/) ? ($mname = "\$" . $1) :
327 # omit -> if $foo->[0]->{bar}, but not ${$foo->[0]}->{bar}
328 ($name =~ /^\\?[\%\@\*\$][^{].*[]}]$/) ? ($mname = $name) :
329 ($mname = $name . '->');
330 $mname .= '->' if $mname =~ /^\*.+\{[A-Z]+\}$/;
332 $sname = $mname . '[' . $i . ']';
333 $out .= $pad . $ipad . '#' . $i if $s->{indent} >= 3;
334 $out .= $pad . $ipad . $s->_dump($v, $sname);
335 $out .= "," if $i++ < $#$val;
337 $out .= $pad . ($s->{xpad} x ($s->{level} - 1)) if $i;
338 $out .= ($name =~ /^\@/) ? ')' : ']';
340 elsif ($realtype eq 'HASH') {
341 my($k, $v, $pad, $lpad, $mname, $pair);
342 $out .= ($name =~ /^\%/) ? '(' : '{';
343 $pad = $s->{sep} . $s->{pad} . $s->{apad};
346 ($name =~ /^\%(.*)$/) ? ($mname = "\$" . $1) :
347 # omit -> if $foo->[0]->{bar}, but not ${$foo->[0]}->{bar}
348 ($name =~ /^\\?[\%\@\*\$][^{].*[]}]$/) ? ($mname = $name) :
349 ($mname = $name . '->');
350 $mname .= '->' if $mname =~ /^\*.+\{[A-Z]+\}$/;
351 my ($sortkeys, $keys, $key) = ("$s->{sortkeys}");
353 if (ref($s->{sortkeys}) eq 'CODE') {
354 $keys = $s->{sortkeys}($val);
355 unless (ref($keys) eq 'ARRAY') {
356 carp "Sortkeys subroutine did not return ARRAYREF";
361 $keys = [ sort keys %$val ];
364 while (($k, $v) = ! $sortkeys ? (each %$val) :
365 @$keys ? ($key = shift(@$keys), $val->{$key}) :
368 my $nk = $s->_dump($k, "");
369 $nk = $1 if !$s->{quotekeys} and $nk =~ /^[\"\']([A-Za-z_]\w*)[\"\']$/;
370 $sname = $mname . '{' . $nk . '}';
371 $out .= $pad . $ipad . $nk . $pair;
373 # temporarily alter apad
374 $s->{apad} .= (" " x (length($nk) + 4)) if $s->{indent} >= 2;
375 $out .= $s->_dump($val->{$k}, $sname) . ",";
376 $s->{apad} = $lpad if $s->{indent} >= 2;
378 if (substr($out, -1) eq ',') {
380 $out .= $pad . ($s->{xpad} x ($s->{level} - 1));
382 $out .= ($name =~ /^\%/) ? ')' : '}';
384 elsif ($realtype eq 'CODE') {
387 my $sub = 'sub ' . (B::Deparse->new)->coderef2text($val);
388 $pad = $s->{sep} . $s->{pad} . $s->{apad} . $s->{xpad} x ($s->{level} - 1);
389 $sub =~ s/\n/$pad/gse;
392 $out .= 'sub { "DUMMY" }';
393 carp "Encountered CODE ref, using dummy placeholder" if $s->{purity};
397 croak "Can\'t handle $realtype type.";
400 if ($realpack) { # we have a blessed ref
401 $out .= ', \'' . $realpack . '\'' . ' )';
402 $out .= '->' . $s->{toaster} . '()' if $s->{toaster} ne '';
403 $s->{apad} = $blesspad;
408 else { # simple scalar
411 # first, catalog the scalar
413 ($id) = ("$ref" =~ /\(([^\(]*)\)$/);
414 if (exists $s->{seen}{$id}) {
415 if ($s->{seen}{$id}[2]) {
416 $out = $s->{seen}{$id}[0];
422 #warn "[>\\$name]\n";
423 $s->{seen}{$id} = ["\\$name", $ref];
426 if (ref($ref) eq 'GLOB' or "$ref" =~ /=GLOB\([^()]+\)$/) { # glob
427 my $name = substr($val, 1);
428 if ($name =~ /^[A-Za-z_][\w:]*$/) {
429 $name =~ s/^main::/::/;
433 $sname = $s->_dump($name, "");
434 $sname = '{' . $sname . '}';
438 local ($s->{level}) = 0;
439 for $k (qw(SCALAR ARRAY HASH)) {
440 my $gval = *$val{$k};
441 next unless defined $gval;
442 next if $k eq "SCALAR" && ! defined $$gval; # always there
444 # _dump can push into @post, so we hold our place using $postlen
445 my $postlen = scalar @post;
446 $post[$postlen] = "\*$sname = ";
447 local ($s->{apad}) = " " x length($post[$postlen]) if $s->{indent} >= 2;
448 $post[$postlen] .= $s->_dump($gval, "\*$sname\{$k\}");
451 $out .= '*' . $sname;
453 elsif (!defined($val)) {
456 elsif ($val =~ /^(?:0|-?[1-9]\d{0,8})\z/) { # safe decimal number
460 if ($s->{useqq} or $val =~ tr/\0-\377//c) {
461 # Fall back to qq if there's unicode
462 $out .= qquote($val, $s->{useqq});
465 $val =~ s/([\\\'])/\\$1/g;
466 $out .= '\'' . $val . '\'';
471 # if we made it this far, $id was added to seen list at current
472 # level, so remove it to get deep copies
473 if ($s->{deepcopy}) {
474 delete($s->{seen}{$id});
477 $s->{seen}{$id}[2] = 1;
484 # non-OO style of earlier version
487 return Data::Dumper->Dump([@_]);
492 return Data::Dumper->Dumpxs([@_], []);
495 sub Dumpf { return Data::Dumper->Dump(@_) }
497 sub Dumpp { print Data::Dumper->Dump(@_) }
500 # reset the "seen" cache
529 defined($v) ? (($s->{pair} = $v), return $s) : $s->{pair};
534 defined($v) ? (($s->{pad} = $v), return $s) : $s->{pad};
539 defined($v) ? (($s->{varname} = $v), return $s) : $s->{varname};
544 defined($v) ? (($s->{purity} = $v), return $s) : $s->{purity};
549 defined($v) ? (($s->{useqq} = $v), return $s) : $s->{useqq};
554 defined($v) ? (($s->{terse} = $v), return $s) : $s->{terse};
559 defined($v) ? (($s->{freezer} = $v), return $s) : $s->{freezer};
564 defined($v) ? (($s->{toaster} = $v), return $s) : $s->{toaster};
569 defined($v) ? (($s->{deepcopy} = $v), return $s) : $s->{deepcopy};
574 defined($v) ? (($s->{quotekeys} = $v), return $s) : $s->{quotekeys};
579 defined($v) ? (($s->{'bless'} = $v), return $s) : $s->{'bless'};
584 defined($v) ? (($s->{'maxdepth'} = $v), return $s) : $s->{'maxdepth'};
589 defined($v) ? (($s->{'useperl'} = $v), return $s) : $s->{'useperl'};
594 defined($v) ? (($s->{'sortkeys'} = $v), return $s) : $s->{'sortkeys'};
599 defined($v) ? (($s->{'deparse'} = $v), return $s) : $s->{'deparse'};
602 # used by qquote below
613 # put a string value in double quotes
616 s/([\\\"\@\$])/\\$1/g;
617 my $bytes; { use bytes; $bytes = length }
618 s/([^\x00-\x7f])/'\x{'.sprintf("%x",ord($1)).'}'/ge if $bytes > length;
619 return qq("$_") unless
620 /[^ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~]/; # fast exit
622 my $high = shift || "";
623 s/([\a\b\t\n\f\r\e])/$esc{$1}/g;
625 if (ord('^')==94) { # ascii
626 # no need for 3 digits in escape for these
627 s/([\0-\037])(?!\d)/'\\'.sprintf('%o',ord($1))/eg;
628 s/([\0-\037\177])/'\\'.sprintf('%03o',ord($1))/eg;
629 # all but last branch below not supported --BEHAVIOR SUBJECT TO CHANGE--
630 if ($high eq "iso8859") {
631 s/([\200-\240])/'\\'.sprintf('%o',ord($1))/eg;
632 } elsif ($high eq "utf8") {
634 # $str =~ s/([^\040-\176])/sprintf "\\x{%04x}", ord($1)/ge;
635 } elsif ($high eq "8bit") {
638 s/([\200-\377])/'\\'.sprintf('%03o',ord($1))/eg;
639 s/([^\040-\176])/sprintf "\\x{%04x}", ord($1)/ge;
643 s{([^ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~])(?!\d)}
644 {my $v = ord($1); '\\'.sprintf(($v <= 037 ? '%o' : '%03o'), $v)}eg;
645 s{([^ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~])}
646 {'\\'.sprintf('%03o',ord($1))}eg;
652 # helper sub to sort hash keys in Perl < 5.8.0 where we don't have
653 # access to sortsv() from XS
654 sub _sortkeys { [ sort keys %{$_[0]} ] }
661 Data::Dumper - stringified perl data structures, suitable for both printing and C<eval>
667 # simple procedural interface
668 print Dumper($foo, $bar);
670 # extended usage with names
671 print Data::Dumper->Dump([$foo, $bar], [qw(foo *ary)]);
673 # configuration variables
675 local $Data::Dumper::Purity = 1;
676 eval Data::Dumper->Dump([$foo, $bar], [qw(foo *ary)]);
680 $d = Data::Dumper->new([$foo, $bar], [qw(foo *ary)]);
684 $d->Purity(1)->Terse(1)->Deepcopy(1);
690 Given a list of scalars or reference variables, writes out their contents in
691 perl syntax. The references can also be objects. The contents of each
692 variable is output in a single Perl statement. Handles self-referential
693 structures correctly.
695 The return value can be C<eval>ed to get back an identical copy of the
696 original reference structure.
698 Any references that are the same as one of those passed in will be named
699 C<$VAR>I<n> (where I<n> is a numeric suffix), and other duplicate references
700 to substructures within C<$VAR>I<n> will be appropriately labeled using arrow
701 notation. You can specify names for individual values to be dumped if you
702 use the C<Dump()> method, or you can change the default C<$VAR> prefix to
703 something else. See C<$Data::Dumper::Varname> and C<$Data::Dumper::Terse>
706 The default output of self-referential structures can be C<eval>ed, but the
707 nested references to C<$VAR>I<n> will be undefined, since a recursive
708 structure cannot be constructed using one Perl statement. You should set the
709 C<Purity> flag to 1 to get additional statements that will correctly fill in
710 these references. Moreover, if C<eval>ed when strictures are in effect,
711 you need to ensure that any variables it accesses are previously declared.
713 In the extended usage form, the references to be dumped can be given
714 user-specified names. If a name begins with a C<*>, the output will
715 describe the dereferenced type of the supplied reference for hashes and
716 arrays, and coderefs. Output of names will be avoided where possible if
717 the C<Terse> flag is set.
719 In many cases, methods that are used to set the internal state of the
720 object will return the object itself, so method calls can be conveniently
723 Several styles of output are possible, all controlled by setting
724 the C<Indent> flag. See L<Configuration Variables or Methods> below
732 =item I<PACKAGE>->new(I<ARRAYREF [>, I<ARRAYREF]>)
734 Returns a newly created C<Data::Dumper> object. The first argument is an
735 anonymous array of values to be dumped. The optional second argument is an
736 anonymous array of names for the values. The names need not have a leading
737 C<$> sign, and must be comprised of alphanumeric characters. You can begin
738 a name with a C<*> to specify that the dereferenced type must be dumped
739 instead of the reference itself, for ARRAY and HASH references.
741 The prefix specified by C<$Data::Dumper::Varname> will be used with a
742 numeric suffix if the name for a value is undefined.
744 Data::Dumper will catalog all references encountered while dumping the
745 values. Cross-references (in the form of names of substructures in perl
746 syntax) will be inserted at all possible points, preserving any structural
747 interdependencies in the original set of values. Structure traversal is
748 depth-first, and proceeds in order from the first supplied value to
751 =item I<$OBJ>->Dump I<or> I<PACKAGE>->Dump(I<ARRAYREF [>, I<ARRAYREF]>)
753 Returns the stringified form of the values stored in the object (preserving
754 the order in which they were supplied to C<new>), subject to the
755 configuration options below. In a list context, it returns a list
756 of strings corresponding to the supplied values.
758 The second form, for convenience, simply calls the C<new> method on its
759 arguments before dumping the object immediately.
761 =item I<$OBJ>->Seen(I<[HASHREF]>)
763 Queries or adds to the internal table of already encountered references.
764 You must use C<Reset> to explicitly clear the table if needed. Such
765 references are not dumped; instead, their names are inserted wherever they
766 are encountered subsequently. This is useful especially for properly
767 dumping subroutine references.
769 Expects an anonymous hash of name => value pairs. Same rules apply for names
770 as in C<new>. If no argument is supplied, will return the "seen" list of
771 name => value pairs, in a list context. Otherwise, returns the object
774 =item I<$OBJ>->Values(I<[ARRAYREF]>)
776 Queries or replaces the internal array of values that will be dumped.
777 When called without arguments, returns the values. Otherwise, returns the
780 =item I<$OBJ>->Names(I<[ARRAYREF]>)
782 Queries or replaces the internal array of user supplied names for the values
783 that will be dumped. When called without arguments, returns the names.
784 Otherwise, returns the object itself.
788 Clears the internal table of "seen" references and returns the object
797 =item Dumper(I<LIST>)
799 Returns the stringified form of the values in the list, subject to the
800 configuration options below. The values will be named C<$VAR>I<n> in the
801 output, where I<n> is a numeric suffix. Will return a list of strings
806 =head2 Configuration Variables or Methods
808 Several configuration variables can be used to control the kind of output
809 generated when using the procedural interface. These variables are usually
810 C<local>ized in a block so that other parts of the code are not affected by
813 These variables determine the default state of the object created by calling
814 the C<new> method, but cannot be used to alter the state of the object
815 thereafter. The equivalent method names should be used instead to query
816 or set the internal state of the object.
818 The method forms return the object itself when called with arguments,
819 so that they can be chained together nicely.
825 $Data::Dumper::Indent I<or> I<$OBJ>->Indent(I<[NEWVAL]>)
827 Controls the style of indentation. It can be set to 0, 1, 2 or 3. Style 0
828 spews output without any newlines, indentation, or spaces between list
829 items. It is the most compact format possible that can still be called
830 valid perl. Style 1 outputs a readable form with newlines but no fancy
831 indentation (each level in the structure is simply indented by a fixed
832 amount of whitespace). Style 2 (the default) outputs a very readable form
833 which takes into account the length of hash keys (so the hash value lines
834 up). Style 3 is like style 2, but also annotates the elements of arrays
835 with their index (but the comment is on its own line, so array output
836 consumes twice the number of lines). Style 2 is the default.
840 $Data::Dumper::Purity I<or> I<$OBJ>->Purity(I<[NEWVAL]>)
842 Controls the degree to which the output can be C<eval>ed to recreate the
843 supplied reference structures. Setting it to 1 will output additional perl
844 statements that will correctly recreate nested references. The default is
849 $Data::Dumper::Pad I<or> I<$OBJ>->Pad(I<[NEWVAL]>)
851 Specifies the string that will be prefixed to every line of the output.
852 Empty string by default.
856 $Data::Dumper::Varname I<or> I<$OBJ>->Varname(I<[NEWVAL]>)
858 Contains the prefix to use for tagging variable names in the output. The
863 $Data::Dumper::Useqq I<or> I<$OBJ>->Useqq(I<[NEWVAL]>)
865 When set, enables the use of double quotes for representing string values.
866 Whitespace other than space will be represented as C<[\n\t\r]>, "unsafe"
867 characters will be backslashed, and unprintable characters will be output as
868 quoted octal integers. Since setting this variable imposes a performance
869 penalty, the default is 0. C<Dump()> will run slower if this flag is set,
870 since the fast XSUB implementation doesn't support it yet.
874 $Data::Dumper::Terse I<or> I<$OBJ>->Terse(I<[NEWVAL]>)
876 When set, Data::Dumper will emit single, non-self-referential values as
877 atoms/terms rather than statements. This means that the C<$VAR>I<n> names
878 will be avoided where possible, but be advised that such output may not
879 always be parseable by C<eval>.
883 $Data::Dumper::Freezer I<or> $I<OBJ>->Freezer(I<[NEWVAL]>)
885 Can be set to a method name, or to an empty string to disable the feature.
886 Data::Dumper will invoke that method via the object before attempting to
887 stringify it. This method can alter the contents of the object (if, for
888 instance, it contains data allocated from C), and even rebless it in a
889 different package. The client is responsible for making sure the specified
890 method can be called via the object, and that the object ends up containing
891 only perl data types after the method has been called. Defaults to an empty
894 If an object does not support the method specified (determined using
895 UNIVERSAL::can()) then the call will be skipped. If the method dies a
896 warning will be generated.
900 $Data::Dumper::Toaster I<or> $I<OBJ>->Toaster(I<[NEWVAL]>)
902 Can be set to a method name, or to an empty string to disable the feature.
903 Data::Dumper will emit a method call for any objects that are to be dumped
904 using the syntax C<bless(DATA, CLASS)-E<gt>METHOD()>. Note that this means that
905 the method specified will have to perform any modifications required on the
906 object (like creating new state within it, and/or reblessing it in a
907 different package) and then return it. The client is responsible for making
908 sure the method can be called via the object, and that it returns a valid
909 object. Defaults to an empty string.
913 $Data::Dumper::Deepcopy I<or> $I<OBJ>->Deepcopy(I<[NEWVAL]>)
915 Can be set to a boolean value to enable deep copies of structures.
916 Cross-referencing will then only be done when absolutely essential
917 (i.e., to break reference cycles). Default is 0.
921 $Data::Dumper::Quotekeys I<or> $I<OBJ>->Quotekeys(I<[NEWVAL]>)
923 Can be set to a boolean value to control whether hash keys are quoted.
924 A false value will avoid quoting hash keys when it looks like a simple
925 string. Default is 1, which will always enclose hash keys in quotes.
929 $Data::Dumper::Bless I<or> $I<OBJ>->Bless(I<[NEWVAL]>)
931 Can be set to a string that specifies an alternative to the C<bless>
932 builtin operator used to create objects. A function with the specified
933 name should exist, and should accept the same arguments as the builtin.
938 $Data::Dumper::Pair I<or> $I<OBJ>->Pair(I<[NEWVAL]>)
940 Can be set to a string that specifies the separator between hash keys
941 and values. To dump nested hash, array and scalar values to JavaScript,
942 use: C<$Data::Dumper::Pair = ' : ';>. Implementing C<bless> in JavaScript
943 is left as an exercise for the reader.
944 A function with the specified name exists, and accepts the same arguments
947 Default is: C< =E<gt> >.
951 $Data::Dumper::Maxdepth I<or> $I<OBJ>->Maxdepth(I<[NEWVAL]>)
953 Can be set to a positive integer that specifies the depth beyond which
954 which we don't venture into a structure. Has no effect when
955 C<Data::Dumper::Purity> is set. (Useful in debugger when we often don't
956 want to see more than enough). Default is 0, which means there is
961 $Data::Dumper::Useperl I<or> $I<OBJ>->Useperl(I<[NEWVAL]>)
963 Can be set to a boolean value which controls whether the pure Perl
964 implementation of C<Data::Dumper> is used. The C<Data::Dumper> module is
965 a dual implementation, with almost all functionality written in both
966 pure Perl and also in XS ('C'). Since the XS version is much faster, it
967 will always be used if possible. This option lets you override the
968 default behavior, usually for testing purposes only. Default is 0, which
969 means the XS implementation will be used if possible.
973 $Data::Dumper::Sortkeys I<or> $I<OBJ>->Sortkeys(I<[NEWVAL]>)
975 Can be set to a boolean value to control whether hash keys are dumped in
976 sorted order. A true value will cause the keys of all hashes to be
977 dumped in Perl's default sort order. Can also be set to a subroutine
978 reference which will be called for each hash that is dumped. In this
979 case C<Data::Dumper> will call the subroutine once for each hash,
980 passing it the reference of the hash. The purpose of the subroutine is
981 to return a reference to an array of the keys that will be dumped, in
982 the order that they should be dumped. Using this feature, you can
983 control both the order of the keys, and which keys are actually used. In
984 other words, this subroutine acts as a filter by which you can exclude
985 certain keys from being dumped. Default is 0, which means that hash keys
990 $Data::Dumper::Deparse I<or> $I<OBJ>->Deparse(I<[NEWVAL]>)
992 Can be set to a boolean value to control whether code references are
993 turned into perl source code. If set to a true value, C<B::Deparse>
994 will be used to get the source of the code reference. Using this option
995 will force using the Perl implementation of the dumper, since the fast
996 XSUB implementation doesn't support it.
998 Caution : use this option only if you know that your coderefs will be
999 properly reconstructed by C<B::Deparse>.
1013 Run these code snippets to get a quick feel for the behavior of this
1014 module. When you are through with these examples, you may want to
1015 add or change the various configuration variables described above,
1016 to see their behavior. (See the testsuite in the Data::Dumper
1017 distribution for more examples.)
1023 sub new {bless {'a' => 1, 'b' => sub { return "foo" }}, $_[0]};
1025 package Fuz; # a weird REF-REF-SCALAR object
1026 sub new {bless \($_ = \ 'fu\'z'), $_[0]};
1031 $boo = [ 1, [], "abcd", \*foo,
1032 {1 => 'a', 023 => 'b', 0x45 => 'c'},
1033 \\"p\q\'r", $foo, $fuz];
1039 $bar = eval(Dumper($boo));
1041 print Dumper($boo), Dumper($bar); # pretty print (no array indices)
1043 $Data::Dumper::Terse = 1; # don't output names where feasible
1044 $Data::Dumper::Indent = 0; # turn off all pretty print
1045 print Dumper($boo), "\n";
1047 $Data::Dumper::Indent = 1; # mild pretty print
1050 $Data::Dumper::Indent = 3; # pretty print with array indices
1053 $Data::Dumper::Useqq = 1; # print strings in double quotes
1056 $Data::Dumper::Pair = " : "; # specify hash key/value separator
1061 # recursive structures
1071 print Data::Dumper->Dump([$a,$b,$c], [qw(a b c)]);
1074 $Data::Dumper::Purity = 1; # fill in the holes for eval
1075 print Data::Dumper->Dump([$a, $b], [qw(*a b)]); # print as @a
1076 print Data::Dumper->Dump([$b, $a], [qw(*b a)]); # print as %b
1079 $Data::Dumper::Deepcopy = 1; # avoid cross-refs
1080 print Data::Dumper->Dump([$b, $a], [qw(*b a)]);
1083 $Data::Dumper::Purity = 0; # avoid cross-refs
1084 print Data::Dumper->Dump([$b, $a], [qw(*b a)]);
1096 print Data::Dumper->Dump([$f], [qw(f)]);
1098 $Data::Dumper::Maxdepth = 3; # no deeper than 3 refs down
1099 print Data::Dumper->Dump([$f], [qw(f)]);
1103 # object-oriented usage
1106 $d = Data::Dumper->new([$a,$b], [qw(a b)]);
1107 $d->Seen({'*c' => $c}); # stash a ref without printing it
1110 $d->Reset->Purity(0); # empty the seen cache
1111 print join "----\n", $d->Dump;
1119 sub new { bless { state => 'awake' }, shift }
1122 print STDERR "preparing to sleep\n";
1123 $s->{state} = 'asleep';
1124 return bless $s, 'Foo::ZZZ';
1130 print STDERR "waking up\n";
1131 $s->{state} = 'awake';
1132 return bless $s, 'Foo';
1138 $b = Data::Dumper->new([$a], ['c']);
1139 $b->Freezer('Freeze');
1140 $b->Toaster('Thaw');
1144 print Data::Dumper->Dump([$d], ['d']);
1148 # symbol substitution (useful for recreating CODE refs)
1151 sub foo { print "foo speaking\n" }
1154 $d = Data::Dumper->new([\&other,$bar],['*other','bar']);
1155 $d->Seen({ '*foo' => \&foo });
1160 # sorting and filtering hash keys
1163 $Data::Dumper::Sortkeys = \&my_filter;
1164 my $foo = { map { (ord, "$_$_$_") } 'I'..'Q' };
1165 my $bar = { %$foo };
1166 my $baz = { reverse %$foo };
1167 print Dumper [ $foo, $bar, $baz ];
1171 # return an array ref containing the hash keys to dump
1172 # in the order that you want them to be dumped
1174 # Sort the keys of %$foo in reverse numeric order
1175 $hash eq $foo ? (sort {$b <=> $a} keys %$hash) :
1176 # Only dump the odd number keys of %$bar
1177 $hash eq $bar ? (grep {$_ % 2} keys %$hash) :
1178 # Sort keys in default order for all other hashes
1185 Due to limitations of Perl subroutine call semantics, you cannot pass an
1186 array or hash. Prepend it with a C<\> to pass its reference instead. This
1187 will be remedied in time, now that Perl has subroutine prototypes.
1188 For now, you need to use the extended usage form, and prepend the
1189 name with a C<*> to output it as a hash or array.
1191 C<Data::Dumper> cheats with CODE references. If a code reference is
1192 encountered in the structure being processed (and if you haven't set
1193 the C<Deparse> flag), an anonymous subroutine that
1194 contains the string '"DUMMY"' will be inserted in its place, and a warning
1195 will be printed if C<Purity> is set. You can C<eval> the result, but bear
1196 in mind that the anonymous sub that gets created is just a placeholder.
1197 Someday, perl will have a switch to cache-on-demand the string
1198 representation of a compiled piece of code, I hope. If you have prior
1199 knowledge of all the code refs that your data structures are likely
1200 to have, you can use the C<Seen> method to pre-seed the internal reference
1201 table and make the dumped output point to them, instead. See L<EXAMPLES>
1204 The C<Useqq> and C<Deparse> flags makes Dump() run slower, since the
1205 XSUB implementation does not support them.
1207 SCALAR objects have the weirdest looking C<bless> workaround.
1209 Pure Perl version of C<Data::Dumper> escapes UTF-8 strings correctly
1210 only in Perl 5.8.0 and later.
1214 Starting from Perl 5.8.1 different runs of Perl will have different
1215 ordering of hash keys. The change was done for greater security,
1216 see L<perlsec/"Algorithmic Complexity Attacks">. This means that
1217 different runs of Perl will have different Data::Dumper outputs if
1218 the data contains hashes. If you need to have identical Data::Dumper
1219 outputs from different runs of Perl, use the environment variable
1220 PERL_HASH_SEED, see L<perlrun/PERL_HASH_SEED>. Using this restores
1221 the old (platform-specific) ordering: an even prettier solution might
1222 be to use the C<Sortkeys> filter of Data::Dumper.
1226 Gurusamy Sarathy gsar@activestate.com
1228 Copyright (c) 1996-98 Gurusamy Sarathy. All rights reserved.
1229 This program is free software; you can redistribute it and/or
1230 modify it under the same terms as Perl itself.
1234 Version 2.121 (Aug 24 2003)