4 # convert perl data structures into perl syntax suitable for both printing
7 # Documentation at the __END__
12 $VERSION = '2.125'; # Don't forget to set version and release date in POD!
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($n) 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);
251 # wrap string in single quotes (escaping if needed)
254 $val =~ s/([\\\'])/\\$1/g;
255 return "'" . $val . "'";
259 # twist, toil and turn;
260 # and recurse, of course.
261 # sometimes sordidly;
262 # and curse if no recourse.
265 my($s, $val, $name) = @_;
267 my($out, $realpack, $realtype, $type, $ipad, $id, $blesspad);
274 # Call the freezer method if it's specified and the object has the
275 # method. Trap errors and warn() instead of die()ing, like the XS
277 my $freezer = $s->{freezer};
278 if ($freezer and UNIVERSAL::can($val, $freezer)) {
279 eval { $val->$freezer() };
280 warn "WARNING(Freezer method call failed): $@" if $@;
283 require Scalar::Util;
284 $realpack = Scalar::Util::blessed($val);
285 $realtype = $realpack ? Scalar::Util::reftype($val) : ref $val;
286 $id = format_refaddr($val);
288 # if it has a name, we need to either look it up, or keep a tab
289 # on it so we know when we hit it later
290 if (defined($name) and length($name)) {
291 # keep a tab on it so that we dont fall into recursive pit
292 if (exists $s->{seen}{$id}) {
293 # if ($s->{expdepth} < $s->{level}) {
294 if ($s->{purity} and $s->{level} > 0) {
295 $out = ($realtype eq 'HASH') ? '{}' :
296 ($realtype eq 'ARRAY') ? '[]' :
298 push @post, $name . " = " . $s->{seen}{$id}[0];
301 $out = $s->{seen}{$id}[0];
302 if ($name =~ /^([\@\%])/) {
304 if ($out =~ /^\\$start/) {
305 $out = substr($out, 1);
308 $out = $start . '{' . $out . '}';
317 $s->{seen}{$id} = [ (($name =~ /^[@%]/) ? ('\\' . $name ) :
318 ($realtype eq 'CODE' and
319 $name =~ /^[*](.*)$/) ? ('\\&' . $1 ) :
326 if ( $realpack and ($] >= 5.009005 ? re::is_regexp($val) : $realpack eq 'Regexp') ) {
328 $no_bless = $realpack eq 'Regexp';
331 # If purity is not set and maxdepth is set, then check depth:
332 # if we have reached maximum depth, return the string
333 # representation of the thing we are currently examining
334 # at this depth (i.e., 'Foo=ARRAY(0xdeadbeef)').
336 and $s->{maxdepth} > 0
337 and $s->{level} >= $s->{maxdepth})
342 # we have a blessed ref
343 if ($realpack and !$no_bless) {
344 $out = $s->{'bless'} . '( ';
345 $blesspad = $s->{apad};
346 $s->{apad} .= ' ' if ($s->{indent} >= 2);
350 $ipad = $s->{xpad} x $s->{level};
354 # This really sucks, re:regexp_pattern is in ext/re/re.xs and not in
355 # universal.c, and even worse we cant just require that re to be loaded
356 # we *have* to use() it.
357 # We should probably move it to universal.c for 5.10.1 and fix this.
358 # Currently we only use re::regexp_pattern when the re is blessed into another
359 # package. This has the disadvantage of meaning that a DD dump won't round trip
360 # as the pattern will be repeatedly wrapped with the same modifiers.
361 # This is an aesthetic issue so we will leave it for now, but we could use
362 # regexp_pattern() in list context to get the modifiers separately.
363 # But since this means loading the full debugging engine in process we wont
364 # bother unless its necessary for accuracy.
365 if (($realpack ne 'Regexp') && defined(*re::regexp_pattern{CODE})) {
366 $pat = re::regexp_pattern($val);
373 elsif ($realtype eq 'SCALAR' || $realtype eq 'REF') {
375 $out .= 'do{\\(my $o = ' . $s->_dump($$val, "\${$name}") . ')}';
378 $out .= '\\' . $s->_dump($$val, "\${$name}");
381 elsif ($realtype eq 'GLOB') {
382 $out .= '\\' . $s->_dump($$val, "*{$name}");
384 elsif ($realtype eq 'ARRAY') {
387 $out .= ($name =~ /^\@/) ? '(' : '[';
388 $pad = $s->{sep} . $s->{pad} . $s->{apad};
389 ($name =~ /^\@(.*)$/) ? ($mname = "\$" . $1) :
390 # omit -> if $foo->[0]->{bar}, but not ${$foo->[0]}->{bar}
391 ($name =~ /^\\?[\%\@\*\$][^{].*[]}]$/) ? ($mname = $name) :
392 ($mname = $name . '->');
393 $mname .= '->' if $mname =~ /^\*.+\{[A-Z]+\}$/;
395 $sname = $mname . '[' . $i . ']';
396 $out .= $pad . $ipad . '#' . $i if $s->{indent} >= 3;
397 $out .= $pad . $ipad . $s->_dump($v, $sname);
398 $out .= "," if $i++ < $#$val;
400 $out .= $pad . ($s->{xpad} x ($s->{level} - 1)) if $i;
401 $out .= ($name =~ /^\@/) ? ')' : ']';
403 elsif ($realtype eq 'HASH') {
404 my($k, $v, $pad, $lpad, $mname, $pair);
405 $out .= ($name =~ /^\%/) ? '(' : '{';
406 $pad = $s->{sep} . $s->{pad} . $s->{apad};
409 ($name =~ /^\%(.*)$/) ? ($mname = "\$" . $1) :
410 # omit -> if $foo->[0]->{bar}, but not ${$foo->[0]}->{bar}
411 ($name =~ /^\\?[\%\@\*\$][^{].*[]}]$/) ? ($mname = $name) :
412 ($mname = $name . '->');
413 $mname .= '->' if $mname =~ /^\*.+\{[A-Z]+\}$/;
414 my ($sortkeys, $keys, $key) = ("$s->{sortkeys}");
416 if (ref($s->{sortkeys}) eq 'CODE') {
417 $keys = $s->{sortkeys}($val);
418 unless (ref($keys) eq 'ARRAY') {
419 carp "Sortkeys subroutine did not return ARRAYREF";
424 $keys = [ sort keys %$val ];
428 # Ensure hash iterator is reset
431 while (($k, $v) = ! $sortkeys ? (each %$val) :
432 @$keys ? ($key = shift(@$keys), $val->{$key}) :
435 my $nk = $s->_dump($k, "");
436 $nk = $1 if !$s->{quotekeys} and $nk =~ /^[\"\']([A-Za-z_]\w*)[\"\']$/;
437 $sname = $mname . '{' . $nk . '}';
438 $out .= $pad . $ipad . $nk . $pair;
440 # temporarily alter apad
441 $s->{apad} .= (" " x (length($nk) + 4)) if $s->{indent} >= 2;
442 $out .= $s->_dump($val->{$k}, $sname) . ",";
443 $s->{apad} = $lpad if $s->{indent} >= 2;
445 if (substr($out, -1) eq ',') {
447 $out .= $pad . ($s->{xpad} x ($s->{level} - 1));
449 $out .= ($name =~ /^\%/) ? ')' : '}';
451 elsif ($realtype eq 'CODE') {
454 my $sub = 'sub ' . (B::Deparse->new)->coderef2text($val);
455 $pad = $s->{sep} . $s->{pad} . $s->{apad} . $s->{xpad} x ($s->{level} - 1);
456 $sub =~ s/\n/$pad/gse;
459 $out .= 'sub { "DUMMY" }';
460 carp "Encountered CODE ref, using dummy placeholder" if $s->{purity};
464 croak "Can\'t handle $realtype type.";
467 if ($realpack and !$no_bless) { # we have a blessed ref
468 $out .= ', ' . _quote($realpack) . ' )';
469 $out .= '->' . $s->{toaster} . '()' if $s->{toaster} ne '';
470 $s->{apad} = $blesspad;
475 else { # simple scalar
478 # first, catalog the scalar
480 $id = format_refaddr($ref);
481 if (exists $s->{seen}{$id}) {
482 if ($s->{seen}{$id}[2]) {
483 $out = $s->{seen}{$id}[0];
489 #warn "[>\\$name]\n";
490 $s->{seen}{$id} = ["\\$name", $ref];
493 if (ref($ref) eq 'GLOB' or "$ref" =~ /=GLOB\([^()]+\)$/) { # glob
494 my $name = substr($val, 1);
495 if ($name =~ /^[A-Za-z_][\w:]*$/) {
496 $name =~ s/^main::/::/;
500 $sname = $s->_dump($name, "");
501 $sname = '{' . $sname . '}';
505 local ($s->{level}) = 0;
506 for $k (qw(SCALAR ARRAY HASH)) {
507 my $gval = *$val{$k};
508 next unless defined $gval;
509 next if $k eq "SCALAR" && ! defined $$gval; # always there
511 # _dump can push into @post, so we hold our place using $postlen
512 my $postlen = scalar @post;
513 $post[$postlen] = "\*$sname = ";
514 local ($s->{apad}) = " " x length($post[$postlen]) if $s->{indent} >= 2;
515 $post[$postlen] .= $s->_dump($gval, "\*$sname\{$k\}");
518 $out .= '*' . $sname;
520 elsif (!defined($val)) {
523 elsif ($val =~ /^(?:0|-?[1-9]\d{0,8})\z/) { # safe decimal number
527 if ($s->{useqq} or $val =~ tr/\0-\377//c) {
528 # Fall back to qq if there's Unicode
529 $out .= qquote($val, $s->{useqq});
532 $out .= _quote($val);
537 # if we made it this far, $id was added to seen list at current
538 # level, so remove it to get deep copies
539 if ($s->{deepcopy}) {
540 delete($s->{seen}{$id});
543 $s->{seen}{$id}[2] = 1;
550 # non-OO style of earlier version
553 return Data::Dumper->Dump([@_]);
558 return Data::Dumper->Dumpxs([@_], []);
561 sub Dumpf { return Data::Dumper->Dump(@_) }
563 sub Dumpp { print Data::Dumper->Dump(@_) }
566 # reset the "seen" cache
595 defined($v) ? (($s->{pair} = $v), return $s) : $s->{pair};
600 defined($v) ? (($s->{pad} = $v), return $s) : $s->{pad};
605 defined($v) ? (($s->{varname} = $v), return $s) : $s->{varname};
610 defined($v) ? (($s->{purity} = $v), return $s) : $s->{purity};
615 defined($v) ? (($s->{useqq} = $v), return $s) : $s->{useqq};
620 defined($v) ? (($s->{terse} = $v), return $s) : $s->{terse};
625 defined($v) ? (($s->{freezer} = $v), return $s) : $s->{freezer};
630 defined($v) ? (($s->{toaster} = $v), return $s) : $s->{toaster};
635 defined($v) ? (($s->{deepcopy} = $v), return $s) : $s->{deepcopy};
640 defined($v) ? (($s->{quotekeys} = $v), return $s) : $s->{quotekeys};
645 defined($v) ? (($s->{'bless'} = $v), return $s) : $s->{'bless'};
650 defined($v) ? (($s->{'maxdepth'} = $v), return $s) : $s->{'maxdepth'};
655 defined($v) ? (($s->{'useperl'} = $v), return $s) : $s->{'useperl'};
660 defined($v) ? (($s->{'sortkeys'} = $v), return $s) : $s->{'sortkeys'};
665 defined($v) ? (($s->{'deparse'} = $v), return $s) : $s->{'deparse'};
668 # used by qquote below
679 # put a string value in double quotes
682 s/([\\\"\@\$])/\\$1/g;
683 my $bytes; { use bytes; $bytes = length }
684 s/([^\x00-\x7f])/'\x{'.sprintf("%x",ord($1)).'}'/ge if $bytes > length;
685 return qq("$_") unless
686 /[^ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~]/; # fast exit
688 my $high = shift || "";
689 s/([\a\b\t\n\f\r\e])/$esc{$1}/g;
691 if (ord('^')==94) { # ascii
692 # no need for 3 digits in escape for these
693 s/([\0-\037])(?!\d)/'\\'.sprintf('%o',ord($1))/eg;
694 s/([\0-\037\177])/'\\'.sprintf('%03o',ord($1))/eg;
695 # all but last branch below not supported --BEHAVIOR SUBJECT TO CHANGE--
696 if ($high eq "iso8859") {
697 s/([\200-\240])/'\\'.sprintf('%o',ord($1))/eg;
698 } elsif ($high eq "utf8") {
700 # $str =~ s/([^\040-\176])/sprintf "\\x{%04x}", ord($1)/ge;
701 } elsif ($high eq "8bit") {
704 s/([\200-\377])/'\\'.sprintf('%03o',ord($1))/eg;
705 s/([^\040-\176])/sprintf "\\x{%04x}", ord($1)/ge;
709 s{([^ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~])(?!\d)}
710 {my $v = ord($1); '\\'.sprintf(($v <= 037 ? '%o' : '%03o'), $v)}eg;
711 s{([^ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~])}
712 {'\\'.sprintf('%03o',ord($1))}eg;
718 # helper sub to sort hash keys in Perl < 5.8.0 where we don't have
719 # access to sortsv() from XS
720 sub _sortkeys { [ sort keys %{$_[0]} ] }
727 Data::Dumper - stringified perl data structures, suitable for both printing and C<eval>
733 # simple procedural interface
734 print Dumper($foo, $bar);
736 # extended usage with names
737 print Data::Dumper->Dump([$foo, $bar], [qw(foo *ary)]);
739 # configuration variables
741 local $Data::Dumper::Purity = 1;
742 eval Data::Dumper->Dump([$foo, $bar], [qw(foo *ary)]);
746 $d = Data::Dumper->new([$foo, $bar], [qw(foo *ary)]);
750 $d->Purity(1)->Terse(1)->Deepcopy(1);
756 Given a list of scalars or reference variables, writes out their contents in
757 perl syntax. The references can also be objects. The content of each
758 variable is output in a single Perl statement. Handles self-referential
759 structures correctly.
761 The return value can be C<eval>ed to get back an identical copy of the
762 original reference structure.
764 Any references that are the same as one of those passed in will be named
765 C<$VAR>I<n> (where I<n> is a numeric suffix), and other duplicate references
766 to substructures within C<$VAR>I<n> will be appropriately labeled using arrow
767 notation. You can specify names for individual values to be dumped if you
768 use the C<Dump()> method, or you can change the default C<$VAR> prefix to
769 something else. See C<$Data::Dumper::Varname> and C<$Data::Dumper::Terse>
772 The default output of self-referential structures can be C<eval>ed, but the
773 nested references to C<$VAR>I<n> will be undefined, since a recursive
774 structure cannot be constructed using one Perl statement. You should set the
775 C<Purity> flag to 1 to get additional statements that will correctly fill in
776 these references. Moreover, if C<eval>ed when strictures are in effect,
777 you need to ensure that any variables it accesses are previously declared.
779 In the extended usage form, the references to be dumped can be given
780 user-specified names. If a name begins with a C<*>, the output will
781 describe the dereferenced type of the supplied reference for hashes and
782 arrays, and coderefs. Output of names will be avoided where possible if
783 the C<Terse> flag is set.
785 In many cases, methods that are used to set the internal state of the
786 object will return the object itself, so method calls can be conveniently
789 Several styles of output are possible, all controlled by setting
790 the C<Indent> flag. See L<Configuration Variables or Methods> below
798 =item I<PACKAGE>->new(I<ARRAYREF [>, I<ARRAYREF]>)
800 Returns a newly created C<Data::Dumper> object. The first argument is an
801 anonymous array of values to be dumped. The optional second argument is an
802 anonymous array of names for the values. The names need not have a leading
803 C<$> sign, and must be comprised of alphanumeric characters. You can begin
804 a name with a C<*> to specify that the dereferenced type must be dumped
805 instead of the reference itself, for ARRAY and HASH references.
807 The prefix specified by C<$Data::Dumper::Varname> will be used with a
808 numeric suffix if the name for a value is undefined.
810 Data::Dumper will catalog all references encountered while dumping the
811 values. Cross-references (in the form of names of substructures in perl
812 syntax) will be inserted at all possible points, preserving any structural
813 interdependencies in the original set of values. Structure traversal is
814 depth-first, and proceeds in order from the first supplied value to
817 =item I<$OBJ>->Dump I<or> I<PACKAGE>->Dump(I<ARRAYREF [>, I<ARRAYREF]>)
819 Returns the stringified form of the values stored in the object (preserving
820 the order in which they were supplied to C<new>), subject to the
821 configuration options below. In a list context, it returns a list
822 of strings corresponding to the supplied values.
824 The second form, for convenience, simply calls the C<new> method on its
825 arguments before dumping the object immediately.
827 =item I<$OBJ>->Seen(I<[HASHREF]>)
829 Queries or adds to the internal table of already encountered references.
830 You must use C<Reset> to explicitly clear the table if needed. Such
831 references are not dumped; instead, their names are inserted wherever they
832 are encountered subsequently. This is useful especially for properly
833 dumping subroutine references.
835 Expects an anonymous hash of name => value pairs. Same rules apply for names
836 as in C<new>. If no argument is supplied, will return the "seen" list of
837 name => value pairs, in a list context. Otherwise, returns the object
840 =item I<$OBJ>->Values(I<[ARRAYREF]>)
842 Queries or replaces the internal array of values that will be dumped.
843 When called without arguments, returns the values. Otherwise, returns the
846 =item I<$OBJ>->Names(I<[ARRAYREF]>)
848 Queries or replaces the internal array of user supplied names for the values
849 that will be dumped. When called without arguments, returns the names.
850 Otherwise, returns the object itself.
854 Clears the internal table of "seen" references and returns the object
863 =item Dumper(I<LIST>)
865 Returns the stringified form of the values in the list, subject to the
866 configuration options below. The values will be named C<$VAR>I<n> in the
867 output, where I<n> is a numeric suffix. Will return a list of strings
872 =head2 Configuration Variables or Methods
874 Several configuration variables can be used to control the kind of output
875 generated when using the procedural interface. These variables are usually
876 C<local>ized in a block so that other parts of the code are not affected by
879 These variables determine the default state of the object created by calling
880 the C<new> method, but cannot be used to alter the state of the object
881 thereafter. The equivalent method names should be used instead to query
882 or set the internal state of the object.
884 The method forms return the object itself when called with arguments,
885 so that they can be chained together nicely.
891 $Data::Dumper::Indent I<or> I<$OBJ>->Indent(I<[NEWVAL]>)
893 Controls the style of indentation. It can be set to 0, 1, 2 or 3. Style 0
894 spews output without any newlines, indentation, or spaces between list
895 items. It is the most compact format possible that can still be called
896 valid perl. Style 1 outputs a readable form with newlines but no fancy
897 indentation (each level in the structure is simply indented by a fixed
898 amount of whitespace). Style 2 (the default) outputs a very readable form
899 which takes into account the length of hash keys (so the hash value lines
900 up). Style 3 is like style 2, but also annotates the elements of arrays
901 with their index (but the comment is on its own line, so array output
902 consumes twice the number of lines). Style 2 is the default.
906 $Data::Dumper::Purity I<or> I<$OBJ>->Purity(I<[NEWVAL]>)
908 Controls the degree to which the output can be C<eval>ed to recreate the
909 supplied reference structures. Setting it to 1 will output additional perl
910 statements that will correctly recreate nested references. The default is
915 $Data::Dumper::Pad I<or> I<$OBJ>->Pad(I<[NEWVAL]>)
917 Specifies the string that will be prefixed to every line of the output.
918 Empty string by default.
922 $Data::Dumper::Varname I<or> I<$OBJ>->Varname(I<[NEWVAL]>)
924 Contains the prefix to use for tagging variable names in the output. The
929 $Data::Dumper::Useqq I<or> I<$OBJ>->Useqq(I<[NEWVAL]>)
931 When set, enables the use of double quotes for representing string values.
932 Whitespace other than space will be represented as C<[\n\t\r]>, "unsafe"
933 characters will be backslashed, and unprintable characters will be output as
934 quoted octal integers. Since setting this variable imposes a performance
935 penalty, the default is 0. C<Dump()> will run slower if this flag is set,
936 since the fast XSUB implementation doesn't support it yet.
940 $Data::Dumper::Terse I<or> I<$OBJ>->Terse(I<[NEWVAL]>)
942 When set, Data::Dumper will emit single, non-self-referential values as
943 atoms/terms rather than statements. This means that the C<$VAR>I<n> names
944 will be avoided where possible, but be advised that such output may not
945 always be parseable by C<eval>.
949 $Data::Dumper::Freezer I<or> $I<OBJ>->Freezer(I<[NEWVAL]>)
951 Can be set to a method name, or to an empty string to disable the feature.
952 Data::Dumper will invoke that method via the object before attempting to
953 stringify it. This method can alter the contents of the object (if, for
954 instance, it contains data allocated from C), and even rebless it in a
955 different package. The client is responsible for making sure the specified
956 method can be called via the object, and that the object ends up containing
957 only perl data types after the method has been called. Defaults to an empty
960 If an object does not support the method specified (determined using
961 UNIVERSAL::can()) then the call will be skipped. If the method dies a
962 warning will be generated.
966 $Data::Dumper::Toaster I<or> $I<OBJ>->Toaster(I<[NEWVAL]>)
968 Can be set to a method name, or to an empty string to disable the feature.
969 Data::Dumper will emit a method call for any objects that are to be dumped
970 using the syntax C<bless(DATA, CLASS)-E<gt>METHOD()>. Note that this means that
971 the method specified will have to perform any modifications required on the
972 object (like creating new state within it, and/or reblessing it in a
973 different package) and then return it. The client is responsible for making
974 sure the method can be called via the object, and that it returns a valid
975 object. Defaults to an empty string.
979 $Data::Dumper::Deepcopy I<or> $I<OBJ>->Deepcopy(I<[NEWVAL]>)
981 Can be set to a boolean value to enable deep copies of structures.
982 Cross-referencing will then only be done when absolutely essential
983 (i.e., to break reference cycles). Default is 0.
987 $Data::Dumper::Quotekeys I<or> $I<OBJ>->Quotekeys(I<[NEWVAL]>)
989 Can be set to a boolean value to control whether hash keys are quoted.
990 A false value will avoid quoting hash keys when it looks like a simple
991 string. Default is 1, which will always enclose hash keys in quotes.
995 $Data::Dumper::Bless I<or> $I<OBJ>->Bless(I<[NEWVAL]>)
997 Can be set to a string that specifies an alternative to the C<bless>
998 builtin operator used to create objects. A function with the specified
999 name should exist, and should accept the same arguments as the builtin.
1000 Default is C<bless>.
1004 $Data::Dumper::Pair I<or> $I<OBJ>->Pair(I<[NEWVAL]>)
1006 Can be set to a string that specifies the separator between hash keys
1007 and values. To dump nested hash, array and scalar values to JavaScript,
1008 use: C<$Data::Dumper::Pair = ' : ';>. Implementing C<bless> in JavaScript
1009 is left as an exercise for the reader.
1010 A function with the specified name exists, and accepts the same arguments
1013 Default is: C< =E<gt> >.
1017 $Data::Dumper::Maxdepth I<or> $I<OBJ>->Maxdepth(I<[NEWVAL]>)
1019 Can be set to a positive integer that specifies the depth beyond which
1020 we don't venture into a structure. Has no effect when
1021 C<Data::Dumper::Purity> is set. (Useful in debugger when we often don't
1022 want to see more than enough). Default is 0, which means there is
1027 $Data::Dumper::Useperl I<or> $I<OBJ>->Useperl(I<[NEWVAL]>)
1029 Can be set to a boolean value which controls whether the pure Perl
1030 implementation of C<Data::Dumper> is used. The C<Data::Dumper> module is
1031 a dual implementation, with almost all functionality written in both
1032 pure Perl and also in XS ('C'). Since the XS version is much faster, it
1033 will always be used if possible. This option lets you override the
1034 default behavior, usually for testing purposes only. Default is 0, which
1035 means the XS implementation will be used if possible.
1039 $Data::Dumper::Sortkeys I<or> $I<OBJ>->Sortkeys(I<[NEWVAL]>)
1041 Can be set to a boolean value to control whether hash keys are dumped in
1042 sorted order. A true value will cause the keys of all hashes to be
1043 dumped in Perl's default sort order. Can also be set to a subroutine
1044 reference which will be called for each hash that is dumped. In this
1045 case C<Data::Dumper> will call the subroutine once for each hash,
1046 passing it the reference of the hash. The purpose of the subroutine is
1047 to return a reference to an array of the keys that will be dumped, in
1048 the order that they should be dumped. Using this feature, you can
1049 control both the order of the keys, and which keys are actually used. In
1050 other words, this subroutine acts as a filter by which you can exclude
1051 certain keys from being dumped. Default is 0, which means that hash keys
1056 $Data::Dumper::Deparse I<or> $I<OBJ>->Deparse(I<[NEWVAL]>)
1058 Can be set to a boolean value to control whether code references are
1059 turned into perl source code. If set to a true value, C<B::Deparse>
1060 will be used to get the source of the code reference. Using this option
1061 will force using the Perl implementation of the dumper, since the fast
1062 XSUB implementation doesn't support it.
1064 Caution : use this option only if you know that your coderefs will be
1065 properly reconstructed by C<B::Deparse>.
1079 Run these code snippets to get a quick feel for the behavior of this
1080 module. When you are through with these examples, you may want to
1081 add or change the various configuration variables described above,
1082 to see their behavior. (See the testsuite in the Data::Dumper
1083 distribution for more examples.)
1089 sub new {bless {'a' => 1, 'b' => sub { return "foo" }}, $_[0]};
1091 package Fuz; # a weird REF-REF-SCALAR object
1092 sub new {bless \($_ = \ 'fu\'z'), $_[0]};
1097 $boo = [ 1, [], "abcd", \*foo,
1098 {1 => 'a', 023 => 'b', 0x45 => 'c'},
1099 \\"p\q\'r", $foo, $fuz];
1105 $bar = eval(Dumper($boo));
1107 print Dumper($boo), Dumper($bar); # pretty print (no array indices)
1109 $Data::Dumper::Terse = 1; # don't output names where feasible
1110 $Data::Dumper::Indent = 0; # turn off all pretty print
1111 print Dumper($boo), "\n";
1113 $Data::Dumper::Indent = 1; # mild pretty print
1116 $Data::Dumper::Indent = 3; # pretty print with array indices
1119 $Data::Dumper::Useqq = 1; # print strings in double quotes
1122 $Data::Dumper::Pair = " : "; # specify hash key/value separator
1127 # recursive structures
1137 print Data::Dumper->Dump([$a,$b,$c], [qw(a b c)]);
1140 $Data::Dumper::Purity = 1; # fill in the holes for eval
1141 print Data::Dumper->Dump([$a, $b], [qw(*a b)]); # print as @a
1142 print Data::Dumper->Dump([$b, $a], [qw(*b a)]); # print as %b
1145 $Data::Dumper::Deepcopy = 1; # avoid cross-refs
1146 print Data::Dumper->Dump([$b, $a], [qw(*b a)]);
1149 $Data::Dumper::Purity = 0; # avoid cross-refs
1150 print Data::Dumper->Dump([$b, $a], [qw(*b a)]);
1162 print Data::Dumper->Dump([$f], [qw(f)]);
1164 $Data::Dumper::Maxdepth = 3; # no deeper than 3 refs down
1165 print Data::Dumper->Dump([$f], [qw(f)]);
1169 # object-oriented usage
1172 $d = Data::Dumper->new([$a,$b], [qw(a b)]);
1173 $d->Seen({'*c' => $c}); # stash a ref without printing it
1176 $d->Reset->Purity(0); # empty the seen cache
1177 print join "----\n", $d->Dump;
1185 sub new { bless { state => 'awake' }, shift }
1188 print STDERR "preparing to sleep\n";
1189 $s->{state} = 'asleep';
1190 return bless $s, 'Foo::ZZZ';
1196 print STDERR "waking up\n";
1197 $s->{state} = 'awake';
1198 return bless $s, 'Foo';
1204 $b = Data::Dumper->new([$a], ['c']);
1205 $b->Freezer('Freeze');
1206 $b->Toaster('Thaw');
1210 print Data::Dumper->Dump([$d], ['d']);
1214 # symbol substitution (useful for recreating CODE refs)
1217 sub foo { print "foo speaking\n" }
1220 $d = Data::Dumper->new([\&other,$bar],['*other','bar']);
1221 $d->Seen({ '*foo' => \&foo });
1226 # sorting and filtering hash keys
1229 $Data::Dumper::Sortkeys = \&my_filter;
1230 my $foo = { map { (ord, "$_$_$_") } 'I'..'Q' };
1231 my $bar = { %$foo };
1232 my $baz = { reverse %$foo };
1233 print Dumper [ $foo, $bar, $baz ];
1237 # return an array ref containing the hash keys to dump
1238 # in the order that you want them to be dumped
1240 # Sort the keys of %$foo in reverse numeric order
1241 $hash eq $foo ? (sort {$b <=> $a} keys %$hash) :
1242 # Only dump the odd number keys of %$bar
1243 $hash eq $bar ? (grep {$_ % 2} keys %$hash) :
1244 # Sort keys in default order for all other hashes
1251 Due to limitations of Perl subroutine call semantics, you cannot pass an
1252 array or hash. Prepend it with a C<\> to pass its reference instead. This
1253 will be remedied in time, now that Perl has subroutine prototypes.
1254 For now, you need to use the extended usage form, and prepend the
1255 name with a C<*> to output it as a hash or array.
1257 C<Data::Dumper> cheats with CODE references. If a code reference is
1258 encountered in the structure being processed (and if you haven't set
1259 the C<Deparse> flag), an anonymous subroutine that
1260 contains the string '"DUMMY"' will be inserted in its place, and a warning
1261 will be printed if C<Purity> is set. You can C<eval> the result, but bear
1262 in mind that the anonymous sub that gets created is just a placeholder.
1263 Someday, perl will have a switch to cache-on-demand the string
1264 representation of a compiled piece of code, I hope. If you have prior
1265 knowledge of all the code refs that your data structures are likely
1266 to have, you can use the C<Seen> method to pre-seed the internal reference
1267 table and make the dumped output point to them, instead. See L</EXAMPLES>
1270 The C<Useqq> and C<Deparse> flags makes Dump() run slower, since the
1271 XSUB implementation does not support them.
1273 SCALAR objects have the weirdest looking C<bless> workaround.
1275 Pure Perl version of C<Data::Dumper> escapes UTF-8 strings correctly
1276 only in Perl 5.8.0 and later.
1280 Starting from Perl 5.8.1 different runs of Perl will have different
1281 ordering of hash keys. The change was done for greater security,
1282 see L<perlsec/"Algorithmic Complexity Attacks">. This means that
1283 different runs of Perl will have different Data::Dumper outputs if
1284 the data contains hashes. If you need to have identical Data::Dumper
1285 outputs from different runs of Perl, use the environment variable
1286 PERL_HASH_SEED, see L<perlrun/PERL_HASH_SEED>. Using this restores
1287 the old (platform-specific) ordering: an even prettier solution might
1288 be to use the C<Sortkeys> filter of Data::Dumper.
1292 Gurusamy Sarathy gsar@activestate.com
1294 Copyright (c) 1996-98 Gurusamy Sarathy. All rights reserved.
1295 This program is free software; you can redistribute it and/or
1296 modify it under the same terms as Perl itself.
1300 Version 2.125 (Aug 8 2009)