4 # convert perl data structures into perl syntax suitable for both printing
7 # Documentation at the __END__
13 $VERSION = '2.154'; # Don't forget to set version and release
14 } # date in POD below!
27 @EXPORT_OK = qw(DumperX);
29 # if run under miniperl, or otherwise lacking dynamic loading,
30 # XSLoader should be attempted to load, or the pure perl flag
31 # toggled on load failure.
34 XSLoader::load( 'Data::Dumper' );
40 # module vars and their defaults
41 $Indent = 2 unless defined $Indent;
42 $Purity = 0 unless defined $Purity;
43 $Pad = "" unless defined $Pad;
44 $Varname = "VAR" unless defined $Varname;
45 $Useqq = 0 unless defined $Useqq;
46 $Terse = 0 unless defined $Terse;
47 $Freezer = "" unless defined $Freezer;
48 $Toaster = "" unless defined $Toaster;
49 $Deepcopy = 0 unless defined $Deepcopy;
50 $Quotekeys = 1 unless defined $Quotekeys;
51 $Bless = "bless" unless defined $Bless;
52 #$Expdepth = 0 unless defined $Expdepth;
53 $Maxdepth = 0 unless defined $Maxdepth;
54 $Pair = ' => ' unless defined $Pair;
55 $Useperl = 0 unless defined $Useperl;
56 $Sortkeys = 0 unless defined $Sortkeys;
57 $Deparse = 0 unless defined $Deparse;
58 $Sparseseen = 0 unless defined $Sparseseen;
59 $Maxrecurse = 1000 unless defined $Maxrecurse;
62 # expects an arrayref of values to be dumped.
63 # can optionally pass an arrayref of names for the values.
64 # names must have leading $ sign stripped. begin the name with *
65 # to cause output of arrays and hashes rather than refs.
70 croak "Usage: PACKAGE->new(ARRAYREF, [ARRAYREF])"
71 unless (defined($v) && (ref($v) eq 'ARRAY'));
72 $n = [] unless (defined($n) && (ref($n) eq 'ARRAY'));
75 level => 0, # current recursive depth
76 indent => $Indent, # various styles of indenting
77 pad => $Pad, # all lines prefixed by this string
78 xpad => "", # padding-per-level
79 apad => "", # added padding for hash keys n such
80 sep => "", # list separator
81 pair => $Pair, # hash key/value separator: defaults to ' => '
82 seen => {}, # local (nested) refs (id => [name, val])
83 todump => $v, # values to dump []
84 names => $n, # optional names for values []
85 varname => $Varname, # prefix to use for tagging nameless ones
86 purity => $Purity, # degree to which output is evalable
87 useqq => $Useqq, # use "" for strings (backslashitis ensues)
88 terse => $Terse, # avoid name output (where feasible)
89 freezer => $Freezer, # name of Freezer method for objects
90 toaster => $Toaster, # name of method to revive objects
91 deepcopy => $Deepcopy, # do not cross-ref, except to stop recursion
92 quotekeys => $Quotekeys, # quote hash keys
93 'bless' => $Bless, # keyword to use for "bless"
94 # expdepth => $Expdepth, # cutoff depth for explicit dumping
95 maxdepth => $Maxdepth, # depth beyond which we give up
96 maxrecurse => $Maxrecurse, # depth beyond which we abort
97 useperl => $Useperl, # use the pure Perl implementation
98 sortkeys => $Sortkeys, # flag or filter for sorting hash keys
99 deparse => $Deparse, # use B::Deparse for coderefs
100 noseen => $Sparseseen, # do not populate the seen hash unless necessary
107 return bless($s, $c);
110 # Packed numeric addresses take less memory. Plus pack is faster than sprintf
112 # Most users of current versions of Data::Dumper will be 5.008 or later.
113 # Anyone on 5.6.1 and 5.6.2 upgrading will be rare (particularly judging by
114 # the bug reports from users on those platforms), so for the common case avoid
115 # complexity, and avoid even compiling the unneeded code.
117 sub init_refaddr_format {
121 require Scalar::Util;
122 pack "J", Scalar::Util::refaddr(shift);
127 no warnings 'redefine';
129 sub init_refaddr_format {
131 my $f = $Config::Config{uvxformat};
133 $refaddr_format = "0x%" . $f;
137 require Scalar::Util;
138 sprintf $refaddr_format, Scalar::Util::refaddr(shift);
146 # add-to or query the table of already seen references
150 if (defined($g) && (ref($g) eq 'HASH')) {
151 init_refaddr_format();
153 while (($k, $v) = each %$g) {
156 $id = format_refaddr($v);
157 if ($k =~ /^[*](.*)$/) {
158 $k = (ref $v eq 'ARRAY') ? ( "\\\@" . $1 ) :
159 (ref $v eq 'HASH') ? ( "\\\%" . $1 ) :
160 (ref $v eq 'CODE') ? ( "\\\&" . $1 ) :
163 elsif ($k !~ /^\$/) {
166 $s->{seen}{$id} = [$k, $v];
169 carp "Only refs supported, ignoring non-ref item \$$k";
173 carp "Value of ref must be defined; ignoring undefined item \$$k";
179 return map { @$_ } values %{$s->{seen}};
184 # set or query the values to be dumped
189 if (ref($v) eq 'ARRAY') {
190 $s->{todump} = [@$v]; # make a copy
194 croak "Argument to Values, if provided, must be array ref";
198 return @{$s->{todump}};
203 # set or query the names of the values to be dumped
208 if (ref($n) eq 'ARRAY') {
209 $s->{names} = [@$n]; # make a copy
213 croak "Argument to Names, if provided, must be array ref";
217 return @{$s->{names}};
225 unless $Data::Dumper::Useperl || (ref($_[0]) && $_[0]->{useperl}) ||
226 $Data::Dumper::Deparse || (ref($_[0]) && $_[0]->{deparse});
231 # dump the refs in the current dumper object.
232 # expects same args as new() if called via package name.
236 my(@out, $val, $name);
239 init_refaddr_format();
241 $s = $s->new(@_) unless ref $s;
243 for $val (@{$s->{todump}}) {
245 $name = $s->{names}[$i++];
246 $name = $s->_refine_name($name, $val, $i);
250 local($s->{apad}) = $s->{apad};
251 $s->{apad} .= ' ' x (length($name) + 3) if $s->{indent} >= 2 and !$s->{terse};
252 $valstr = $s->_dump($val, $name);
255 $valstr = "$name = " . $valstr . ';' if @post or !$s->{terse};
256 my $out = $s->_compose_out($valstr, \@post);
260 return wantarray ? @out : join('', @out);
263 # wrap string in single quotes (escaping if needed)
266 $val =~ s/([\\\'])/\\$1/g;
267 return "'" . $val . "'";
270 # Old Perls (5.14-) have trouble resetting vstring magic when it is no
272 use constant _bad_vsmg => defined &_vstring && (_vstring(~v0)||'') eq "v0";
275 # twist, toil and turn;
276 # and recurse, of course.
277 # sometimes sordidly;
278 # and curse if no recourse.
281 my($s, $val, $name) = @_;
282 my($out, $type, $id, $sname);
289 # Call the freezer method if it's specified and the object has the
290 # method. Trap errors and warn() instead of die()ing, like the XS
292 my $freezer = $s->{freezer};
293 if ($freezer and UNIVERSAL::can($val, $freezer)) {
294 eval { $val->$freezer() };
295 warn "WARNING(Freezer method call failed): $@" if $@;
298 require Scalar::Util;
299 my $realpack = Scalar::Util::blessed($val);
300 my $realtype = $realpack ? Scalar::Util::reftype($val) : ref $val;
301 $id = format_refaddr($val);
303 # Note: By this point $name is always defined and of non-zero length.
304 # Keep a tab on it so that we do not fall into recursive pit.
305 if (exists $s->{seen}{$id}) {
306 if ($s->{purity} and $s->{level} > 0) {
307 $out = ($realtype eq 'HASH') ? '{}' :
308 ($realtype eq 'ARRAY') ? '[]' :
310 push @post, $name . " = " . $s->{seen}{$id}[0];
313 $out = $s->{seen}{$id}[0];
314 if ($name =~ /^([\@\%])/) {
316 if ($out =~ /^\\$start/) {
317 $out = substr($out, 1);
320 $out = $start . '{' . $out . '}';
328 $s->{seen}{$id} = [ (
331 : ($realtype eq 'CODE' and $name =~ /^[*](.*)$/)
338 if ( $realpack and ($] >= 5.009005 ? re::is_regexp($val) : $realpack eq 'Regexp') ) {
340 $no_bless = $realpack eq 'Regexp';
343 # If purity is not set and maxdepth is set, then check depth:
344 # if we have reached maximum depth, return the string
345 # representation of the thing we are currently examining
346 # at this depth (i.e., 'Foo=ARRAY(0xdeadbeef)').
348 and defined($s->{maxdepth})
349 and $s->{maxdepth} > 0
350 and $s->{level} >= $s->{maxdepth})
355 # avoid recursing infinitely [perl #122111]
356 if ($s->{maxrecurse} > 0
357 and $s->{level} >= $s->{maxrecurse}) {
358 die "Recursion limit of $s->{maxrecurse} exceeded";
361 # we have a blessed ref
363 if ($realpack and !$no_bless) {
364 $out = $s->{'bless'} . '( ';
365 $blesspad = $s->{apad};
366 $s->{apad} .= ' ' if ($s->{indent} >= 2);
370 my $ipad = $s->{xpad} x $s->{level};
375 if (defined(*re::regexp_pattern{CODE})) {
376 ($pat, $flags) = re::regexp_pattern($val);
381 $pat =~ s <(\\.)|/> { $1 || '\\/' }ge;
382 $out .= "qr/$pat/$flags";
384 elsif ($realtype eq 'SCALAR' || $realtype eq 'REF'
385 || $realtype eq 'VSTRING') {
387 $out .= 'do{\\(my $o = ' . $s->_dump($$val, "\${$name}") . ')}';
390 $out .= '\\' . $s->_dump($$val, "\${$name}");
393 elsif ($realtype eq 'GLOB') {
394 $out .= '\\' . $s->_dump($$val, "*{$name}");
396 elsif ($realtype eq 'ARRAY') {
399 $out .= ($name =~ /^\@/) ? '(' : '[';
400 $pad = $s->{sep} . $s->{pad} . $s->{apad};
401 ($name =~ /^\@(.*)$/) ? ($mname = "\$" . $1) :
402 # omit -> if $foo->[0]->{bar}, but not ${$foo->[0]}->{bar}
403 ($name =~ /^\\?[\%\@\*\$][^{].*[]}]$/) ? ($mname = $name) :
404 ($mname = $name . '->');
405 $mname .= '->' if $mname =~ /^\*.+\{[A-Z]+\}$/;
407 $sname = $mname . '[' . $i . ']';
408 $out .= $pad . $ipad . '#' . $i
409 if $s->{indent} >= 3;
410 $out .= $pad . $ipad . $s->_dump($v, $sname);
411 $out .= "," if $i++ < $#$val;
413 $out .= $pad . ($s->{xpad} x ($s->{level} - 1)) if $i;
414 $out .= ($name =~ /^\@/) ? ')' : ']';
416 elsif ($realtype eq 'HASH') {
417 my ($k, $v, $pad, $lpad, $mname, $pair);
418 $out .= ($name =~ /^\%/) ? '(' : '{';
419 $pad = $s->{sep} . $s->{pad} . $s->{apad};
422 ($name =~ /^\%(.*)$/) ? ($mname = "\$" . $1) :
423 # omit -> if $foo->[0]->{bar}, but not ${$foo->[0]}->{bar}
424 ($name =~ /^\\?[\%\@\*\$][^{].*[]}]$/) ? ($mname = $name) :
425 ($mname = $name . '->');
426 $mname .= '->' if $mname =~ /^\*.+\{[A-Z]+\}$/;
427 my $sortkeys = defined($s->{sortkeys}) ? $s->{sortkeys} : '';
430 if (ref($s->{sortkeys}) eq 'CODE') {
431 $keys = $s->{sortkeys}($val);
432 unless (ref($keys) eq 'ARRAY') {
433 carp "Sortkeys subroutine did not return ARRAYREF";
438 $keys = [ sort keys %$val ];
442 # Ensure hash iterator is reset
446 while (($k, $v) = ! $sortkeys ? (each %$val) :
447 @$keys ? ($key = shift(@$keys), $val->{$key}) :
450 my $nk = $s->_dump($k, "");
452 # _dump doesn't quote numbers of this form
453 if ($s->{quotekeys} && $nk =~ /^(?:0|-?[1-9][0-9]{0,8})\z/) {
454 $nk = $s->{useqq} ? qq("$nk") : qq('$nk');
456 elsif (!$s->{quotekeys} and $nk =~ /^[\"\']([A-Za-z_]\w*)[\"\']$/) {
460 $sname = $mname . '{' . $nk . '}';
461 $out .= $pad . $ipad . $nk . $pair;
463 # temporarily alter apad
464 $s->{apad} .= (" " x (length($nk) + 4))
465 if $s->{indent} >= 2;
466 $out .= $s->_dump($val->{$k}, $sname) . ",";
468 if $s->{indent} >= 2;
470 if (substr($out, -1) eq ',') {
472 $out .= $pad . ($s->{xpad} x ($s->{level} - 1));
474 $out .= ($name =~ /^\%/) ? ')' : '}';
476 elsif ($realtype eq 'CODE') {
479 my $sub = 'sub ' . (B::Deparse->new)->coderef2text($val);
480 $pad = $s->{sep} . $s->{pad} . $s->{apad} . $s->{xpad} x ($s->{level} - 1);
481 $sub =~ s/\n/$pad/gse;
485 $out .= 'sub { "DUMMY" }';
486 carp "Encountered CODE ref, using dummy placeholder" if $s->{purity};
490 croak "Can't handle '$realtype' type";
493 if ($realpack and !$no_bless) { # we have a blessed ref
494 $out .= ', ' . _quote($realpack) . ' )';
495 $out .= '->' . $s->{toaster} . '()'
496 if $s->{toaster} ne '';
497 $s->{apad} = $blesspad;
501 else { # simple scalar
505 # first, catalog the scalar
507 $id = format_refaddr($ref);
508 if (exists $s->{seen}{$id}) {
509 if ($s->{seen}{$id}[2]) {
510 $out = $s->{seen}{$id}[0];
516 #warn "[>\\$name]\n";
517 $s->{seen}{$id} = ["\\$name", $ref];
521 if (ref($ref) eq 'GLOB') { # glob
522 my $name = substr($val, 1);
523 if ($name =~ /^[A-Za-z_][\w:]*$/ && $name ne 'main::') {
524 $name =~ s/^main::/::/;
529 $name eq 'main::' || $] < 5.007 && $name eq "main::\0"
534 $sname = '{' . $sname . '}';
538 local ($s->{level}) = 0;
539 for $k (qw(SCALAR ARRAY HASH)) {
540 my $gval = *$val{$k};
541 next unless defined $gval;
542 next if $k eq "SCALAR" && ! defined $$gval; # always there
544 # _dump can push into @post, so we hold our place using $postlen
545 my $postlen = scalar @post;
546 $post[$postlen] = "\*$sname = ";
547 local ($s->{apad}) = " " x length($post[$postlen]) if $s->{indent} >= 2;
548 $post[$postlen] .= $s->_dump($gval, "\*$sname\{$k\}");
551 $out .= '*' . $sname;
553 elsif (!defined($val)) {
556 elsif (defined &_vstring and $v = _vstring($val)
557 and !_bad_vsmg || eval $v eq $val) {
560 elsif (!defined &_vstring
561 and ref $ref eq 'VSTRING' || eval{Scalar::Util::isvstring($val)}) {
562 $out .= sprintf "%vd", $val;
564 # \d here would treat "1\x{660}" as a safe decimal number
565 elsif ($val =~ /^(?:0|-?[1-9][0-9]{0,8})\z/) { # safe decimal number
569 if ($s->{useqq} or $val =~ tr/\0-\377//c) {
570 # Fall back to qq if there's Unicode
571 $out .= qquote($val, $s->{useqq});
574 $out .= _quote($val);
579 # if we made it this far, $id was added to seen list at current
580 # level, so remove it to get deep copies
581 if ($s->{deepcopy}) {
582 delete($s->{seen}{$id});
585 $s->{seen}{$id}[2] = 1;
592 # non-OO style of earlier version
595 return Data::Dumper->Dump([@_]);
600 return Data::Dumper->Dumpxs([@_], []);
604 # reset the "seen" cache
633 defined($v) ? (($s->{pair} = $v), return $s) : $s->{pair};
638 defined($v) ? (($s->{pad} = $v), return $s) : $s->{pad};
643 defined($v) ? (($s->{varname} = $v), return $s) : $s->{varname};
648 defined($v) ? (($s->{purity} = $v), return $s) : $s->{purity};
653 defined($v) ? (($s->{useqq} = $v), return $s) : $s->{useqq};
658 defined($v) ? (($s->{terse} = $v), return $s) : $s->{terse};
663 defined($v) ? (($s->{freezer} = $v), return $s) : $s->{freezer};
668 defined($v) ? (($s->{toaster} = $v), return $s) : $s->{toaster};
673 defined($v) ? (($s->{deepcopy} = $v), return $s) : $s->{deepcopy};
678 defined($v) ? (($s->{quotekeys} = $v), return $s) : $s->{quotekeys};
683 defined($v) ? (($s->{'bless'} = $v), return $s) : $s->{'bless'};
688 defined($v) ? (($s->{'maxdepth'} = $v), return $s) : $s->{'maxdepth'};
693 defined($v) ? (($s->{'maxrecurse'} = $v), return $s) : $s->{'maxrecurse'};
698 defined($v) ? (($s->{'useperl'} = $v), return $s) : $s->{'useperl'};
703 defined($v) ? (($s->{'sortkeys'} = $v), return $s) : $s->{'sortkeys'};
708 defined($v) ? (($s->{'deparse'} = $v), return $s) : $s->{'deparse'};
713 defined($v) ? (($s->{'noseen'} = $v), return $s) : $s->{'noseen'};
716 # used by qquote below
727 # put a string value in double quotes
730 s/([\\\"\@\$])/\\$1/g;
731 my $bytes; { use bytes; $bytes = length }
732 s/([[:^ascii:]])/'\x{'.sprintf("%x",ord($1)).'}'/ge if $bytes > length;
733 return qq("$_") unless
734 /[^ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~]/; # fast exit
736 my $high = shift || "";
737 s/([\a\b\t\n\f\r\e])/$esc{$1}/g;
739 if (ord('^')==94) { # ascii
740 # no need for 3 digits in escape for these
741 s/([\0-\037])(?!\d)/'\\'.sprintf('%o',ord($1))/eg;
742 s/([\0-\037\177])/'\\'.sprintf('%03o',ord($1))/eg;
743 # all but last branch below not supported --BEHAVIOR SUBJECT TO CHANGE--
744 if ($high eq "iso8859") {
745 s/([\200-\240])/'\\'.sprintf('%o',ord($1))/eg;
746 } elsif ($high eq "utf8") {
748 # $str =~ s/([^\040-\176])/sprintf "\\x{%04x}", ord($1)/ge;
749 } elsif ($high eq "8bit") {
752 s/([\200-\377])/'\\'.sprintf('%03o',ord($1))/eg;
753 s/([^\040-\176])/sprintf "\\x{%04x}", ord($1)/ge;
757 s{([^ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~])(?!\d)}
758 {my $v = ord($1); '\\'.sprintf(($v <= 037 ? '%o' : '%03o'), $v)}eg;
759 s{([^ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~])}
760 {'\\'.sprintf('%03o',ord($1))}eg;
766 # helper sub to sort hash keys in Perl < 5.8.0 where we don't have
767 # access to sortsv() from XS
768 sub _sortkeys { [ sort keys %{$_[0]} ] }
772 my ($name, $val, $i) = @_;
774 if ($name =~ /^[*](.*)$/) {
776 $name = (ref $val eq 'ARRAY') ? ( "\@" . $1 ) :
777 (ref $val eq 'HASH') ? ( "\%" . $1 ) :
778 (ref $val eq 'CODE') ? ( "\*" . $1 ) :
785 elsif ($name !~ /^\$/) {
786 $name = "\$" . $name;
789 else { # no names provided
790 $name = "\$" . $s->{varname} . $i;
797 my ($valstr, $postref) = @_;
799 $out .= $s->{pad} . $valstr . $s->{sep};
802 join(';' . $s->{sep} . $s->{pad}, @{$postref}) .
814 Data::Dumper - stringified perl data structures, suitable for both printing and C<eval>
820 # simple procedural interface
821 print Dumper($foo, $bar);
823 # extended usage with names
824 print Data::Dumper->Dump([$foo, $bar], [qw(foo *ary)]);
826 # configuration variables
828 local $Data::Dumper::Purity = 1;
829 eval Data::Dumper->Dump([$foo, $bar], [qw(foo *ary)]);
833 $d = Data::Dumper->new([$foo, $bar], [qw(foo *ary)]);
837 $d->Purity(1)->Terse(1)->Deepcopy(1);
843 Given a list of scalars or reference variables, writes out their contents in
844 perl syntax. The references can also be objects. The content of each
845 variable is output in a single Perl statement. Handles self-referential
846 structures correctly.
848 The return value can be C<eval>ed to get back an identical copy of the
849 original reference structure. (Please do consider the security implications
850 of eval'ing code from untrusted sources!)
852 Any references that are the same as one of those passed in will be named
853 C<$VAR>I<n> (where I<n> is a numeric suffix), and other duplicate references
854 to substructures within C<$VAR>I<n> will be appropriately labeled using arrow
855 notation. You can specify names for individual values to be dumped if you
856 use the C<Dump()> method, or you can change the default C<$VAR> prefix to
857 something else. See C<$Data::Dumper::Varname> and C<$Data::Dumper::Terse>
860 The default output of self-referential structures can be C<eval>ed, but the
861 nested references to C<$VAR>I<n> will be undefined, since a recursive
862 structure cannot be constructed using one Perl statement. You should set the
863 C<Purity> flag to 1 to get additional statements that will correctly fill in
864 these references. Moreover, if C<eval>ed when strictures are in effect,
865 you need to ensure that any variables it accesses are previously declared.
867 In the extended usage form, the references to be dumped can be given
868 user-specified names. If a name begins with a C<*>, the output will
869 describe the dereferenced type of the supplied reference for hashes and
870 arrays, and coderefs. Output of names will be avoided where possible if
871 the C<Terse> flag is set.
873 In many cases, methods that are used to set the internal state of the
874 object will return the object itself, so method calls can be conveniently
877 Several styles of output are possible, all controlled by setting
878 the C<Indent> flag. See L<Configuration Variables or Methods> below
886 =item I<PACKAGE>->new(I<ARRAYREF [>, I<ARRAYREF]>)
888 Returns a newly created C<Data::Dumper> object. The first argument is an
889 anonymous array of values to be dumped. The optional second argument is an
890 anonymous array of names for the values. The names need not have a leading
891 C<$> sign, and must be comprised of alphanumeric characters. You can begin
892 a name with a C<*> to specify that the dereferenced type must be dumped
893 instead of the reference itself, for ARRAY and HASH references.
895 The prefix specified by C<$Data::Dumper::Varname> will be used with a
896 numeric suffix if the name for a value is undefined.
898 Data::Dumper will catalog all references encountered while dumping the
899 values. Cross-references (in the form of names of substructures in perl
900 syntax) will be inserted at all possible points, preserving any structural
901 interdependencies in the original set of values. Structure traversal is
902 depth-first, and proceeds in order from the first supplied value to
905 =item I<$OBJ>->Dump I<or> I<PACKAGE>->Dump(I<ARRAYREF [>, I<ARRAYREF]>)
907 Returns the stringified form of the values stored in the object (preserving
908 the order in which they were supplied to C<new>), subject to the
909 configuration options below. In a list context, it returns a list
910 of strings corresponding to the supplied values.
912 The second form, for convenience, simply calls the C<new> method on its
913 arguments before dumping the object immediately.
915 =item I<$OBJ>->Seen(I<[HASHREF]>)
917 Queries or adds to the internal table of already encountered references.
918 You must use C<Reset> to explicitly clear the table if needed. Such
919 references are not dumped; instead, their names are inserted wherever they
920 are encountered subsequently. This is useful especially for properly
921 dumping subroutine references.
923 Expects an anonymous hash of name => value pairs. Same rules apply for names
924 as in C<new>. If no argument is supplied, will return the "seen" list of
925 name => value pairs, in a list context. Otherwise, returns the object
928 =item I<$OBJ>->Values(I<[ARRAYREF]>)
930 Queries or replaces the internal array of values that will be dumped. When
931 called without arguments, returns the values as a list. When called with a
932 reference to an array of replacement values, returns the object itself. When
933 called with any other type of argument, dies.
935 =item I<$OBJ>->Names(I<[ARRAYREF]>)
937 Queries or replaces the internal array of user supplied names for the values
938 that will be dumped. When called without arguments, returns the names. When
939 called with an array of replacement names, returns the object itself. If the
940 number of replacement names exceeds the number of values to be named, the
941 excess names will not be used. If the number of replacement names falls short
942 of the number of values to be named, the list of replacement names will be
943 exhausted and remaining values will not be renamed. When
944 called with any other type of argument, dies.
948 Clears the internal table of "seen" references and returns the object
957 =item Dumper(I<LIST>)
959 Returns the stringified form of the values in the list, subject to the
960 configuration options below. The values will be named C<$VAR>I<n> in the
961 output, where I<n> is a numeric suffix. Will return a list of strings
966 =head2 Configuration Variables or Methods
968 Several configuration variables can be used to control the kind of output
969 generated when using the procedural interface. These variables are usually
970 C<local>ized in a block so that other parts of the code are not affected by
973 These variables determine the default state of the object created by calling
974 the C<new> method, but cannot be used to alter the state of the object
975 thereafter. The equivalent method names should be used instead to query
976 or set the internal state of the object.
978 The method forms return the object itself when called with arguments,
979 so that they can be chained together nicely.
985 $Data::Dumper::Indent I<or> I<$OBJ>->Indent(I<[NEWVAL]>)
987 Controls the style of indentation. It can be set to 0, 1, 2 or 3. Style 0
988 spews output without any newlines, indentation, or spaces between list
989 items. It is the most compact format possible that can still be called
990 valid perl. Style 1 outputs a readable form with newlines but no fancy
991 indentation (each level in the structure is simply indented by a fixed
992 amount of whitespace). Style 2 (the default) outputs a very readable form
993 which takes into account the length of hash keys (so the hash value lines
994 up). Style 3 is like style 2, but also annotates the elements of arrays
995 with their index (but the comment is on its own line, so array output
996 consumes twice the number of lines). Style 2 is the default.
1000 $Data::Dumper::Purity I<or> I<$OBJ>->Purity(I<[NEWVAL]>)
1002 Controls the degree to which the output can be C<eval>ed to recreate the
1003 supplied reference structures. Setting it to 1 will output additional perl
1004 statements that will correctly recreate nested references. The default is
1009 $Data::Dumper::Pad I<or> I<$OBJ>->Pad(I<[NEWVAL]>)
1011 Specifies the string that will be prefixed to every line of the output.
1012 Empty string by default.
1016 $Data::Dumper::Varname I<or> I<$OBJ>->Varname(I<[NEWVAL]>)
1018 Contains the prefix to use for tagging variable names in the output. The
1023 $Data::Dumper::Useqq I<or> I<$OBJ>->Useqq(I<[NEWVAL]>)
1025 When set, enables the use of double quotes for representing string values.
1026 Whitespace other than space will be represented as C<[\n\t\r]>, "unsafe"
1027 characters will be backslashed, and unprintable characters will be output as
1028 quoted octal integers. Since setting this variable imposes a performance
1029 penalty, the default is 0. C<Dump()> will run slower if this flag is set,
1030 since the fast XSUB implementation doesn't support it yet.
1034 $Data::Dumper::Terse I<or> I<$OBJ>->Terse(I<[NEWVAL]>)
1036 When set, Data::Dumper will emit single, non-self-referential values as
1037 atoms/terms rather than statements. This means that the C<$VAR>I<n> names
1038 will be avoided where possible, but be advised that such output may not
1039 always be parseable by C<eval>.
1043 $Data::Dumper::Freezer I<or> $I<OBJ>->Freezer(I<[NEWVAL]>)
1045 Can be set to a method name, or to an empty string to disable the feature.
1046 Data::Dumper will invoke that method via the object before attempting to
1047 stringify it. This method can alter the contents of the object (if, for
1048 instance, it contains data allocated from C), and even rebless it in a
1049 different package. The client is responsible for making sure the specified
1050 method can be called via the object, and that the object ends up containing
1051 only perl data types after the method has been called. Defaults to an empty
1054 If an object does not support the method specified (determined using
1055 UNIVERSAL::can()) then the call will be skipped. If the method dies a
1056 warning will be generated.
1060 $Data::Dumper::Toaster I<or> $I<OBJ>->Toaster(I<[NEWVAL]>)
1062 Can be set to a method name, or to an empty string to disable the feature.
1063 Data::Dumper will emit a method call for any objects that are to be dumped
1064 using the syntax C<bless(DATA, CLASS)-E<gt>METHOD()>. Note that this means that
1065 the method specified will have to perform any modifications required on the
1066 object (like creating new state within it, and/or reblessing it in a
1067 different package) and then return it. The client is responsible for making
1068 sure the method can be called via the object, and that it returns a valid
1069 object. Defaults to an empty string.
1073 $Data::Dumper::Deepcopy I<or> $I<OBJ>->Deepcopy(I<[NEWVAL]>)
1075 Can be set to a boolean value to enable deep copies of structures.
1076 Cross-referencing will then only be done when absolutely essential
1077 (i.e., to break reference cycles). Default is 0.
1081 $Data::Dumper::Quotekeys I<or> $I<OBJ>->Quotekeys(I<[NEWVAL]>)
1083 Can be set to a boolean value to control whether hash keys are quoted.
1084 A defined false value will avoid quoting hash keys when it looks like a simple
1085 string. Default is 1, which will always enclose hash keys in quotes.
1089 $Data::Dumper::Bless I<or> $I<OBJ>->Bless(I<[NEWVAL]>)
1091 Can be set to a string that specifies an alternative to the C<bless>
1092 builtin operator used to create objects. A function with the specified
1093 name should exist, and should accept the same arguments as the builtin.
1094 Default is C<bless>.
1098 $Data::Dumper::Pair I<or> $I<OBJ>->Pair(I<[NEWVAL]>)
1100 Can be set to a string that specifies the separator between hash keys
1101 and values. To dump nested hash, array and scalar values to JavaScript,
1102 use: C<$Data::Dumper::Pair = ' : ';>. Implementing C<bless> in JavaScript
1103 is left as an exercise for the reader.
1104 A function with the specified name exists, and accepts the same arguments
1107 Default is: C< =E<gt> >.
1111 $Data::Dumper::Maxdepth I<or> $I<OBJ>->Maxdepth(I<[NEWVAL]>)
1113 Can be set to a positive integer that specifies the depth beyond which
1114 we don't venture into a structure. Has no effect when
1115 C<Data::Dumper::Purity> is set. (Useful in debugger when we often don't
1116 want to see more than enough). Default is 0, which means there is
1121 $Data::Dumper::Maxrecurse I<or> $I<OBJ>->Maxrecurse(I<[NEWVAL]>)
1123 Can be set to a positive integer that specifies the depth beyond which
1124 recursion into a structure will throw an exception. This is intended
1125 as a security measure to prevent perl running out of stack space when
1126 dumping an excessively deep structure. Can be set to 0 to remove the
1127 limit. Default is 1000.
1131 $Data::Dumper::Useperl I<or> $I<OBJ>->Useperl(I<[NEWVAL]>)
1133 Can be set to a boolean value which controls whether the pure Perl
1134 implementation of C<Data::Dumper> is used. The C<Data::Dumper> module is
1135 a dual implementation, with almost all functionality written in both
1136 pure Perl and also in XS ('C'). Since the XS version is much faster, it
1137 will always be used if possible. This option lets you override the
1138 default behavior, usually for testing purposes only. Default is 0, which
1139 means the XS implementation will be used if possible.
1143 $Data::Dumper::Sortkeys I<or> $I<OBJ>->Sortkeys(I<[NEWVAL]>)
1145 Can be set to a boolean value to control whether hash keys are dumped in
1146 sorted order. A true value will cause the keys of all hashes to be
1147 dumped in Perl's default sort order. Can also be set to a subroutine
1148 reference which will be called for each hash that is dumped. In this
1149 case C<Data::Dumper> will call the subroutine once for each hash,
1150 passing it the reference of the hash. The purpose of the subroutine is
1151 to return a reference to an array of the keys that will be dumped, in
1152 the order that they should be dumped. Using this feature, you can
1153 control both the order of the keys, and which keys are actually used. In
1154 other words, this subroutine acts as a filter by which you can exclude
1155 certain keys from being dumped. Default is 0, which means that hash keys
1160 $Data::Dumper::Deparse I<or> $I<OBJ>->Deparse(I<[NEWVAL]>)
1162 Can be set to a boolean value to control whether code references are
1163 turned into perl source code. If set to a true value, C<B::Deparse>
1164 will be used to get the source of the code reference. Using this option
1165 will force using the Perl implementation of the dumper, since the fast
1166 XSUB implementation doesn't support it.
1168 Caution : use this option only if you know that your coderefs will be
1169 properly reconstructed by C<B::Deparse>.
1173 $Data::Dumper::Sparseseen I<or> $I<OBJ>->Sparseseen(I<[NEWVAL]>)
1175 By default, Data::Dumper builds up the "seen" hash of scalars that
1176 it has encountered during serialization. This is very expensive.
1177 This seen hash is necessary to support and even just detect circular
1178 references. It is exposed to the user via the C<Seen()> call both
1179 for writing and reading.
1181 If you, as a user, do not need explicit access to the "seen" hash,
1182 then you can set the C<Sparseseen> option to allow Data::Dumper
1183 to eschew building the "seen" hash for scalars that are known not
1184 to possess more than one reference. This speeds up serialization
1185 considerably if you use the XS implementation.
1187 Note: If you turn on C<Sparseseen>, then you must not rely on the
1188 content of the seen hash since its contents will be an
1189 implementation detail!
1203 Run these code snippets to get a quick feel for the behavior of this
1204 module. When you are through with these examples, you may want to
1205 add or change the various configuration variables described above,
1206 to see their behavior. (See the testsuite in the Data::Dumper
1207 distribution for more examples.)
1213 sub new {bless {'a' => 1, 'b' => sub { return "foo" }}, $_[0]};
1215 package Fuz; # a weird REF-REF-SCALAR object
1216 sub new {bless \($_ = \ 'fu\'z'), $_[0]};
1221 $boo = [ 1, [], "abcd", \*foo,
1222 {1 => 'a', 023 => 'b', 0x45 => 'c'},
1223 \\"p\q\'r", $foo, $fuz];
1229 $bar = eval(Dumper($boo));
1231 print Dumper($boo), Dumper($bar); # pretty print (no array indices)
1233 $Data::Dumper::Terse = 1; # don't output names where feasible
1234 $Data::Dumper::Indent = 0; # turn off all pretty print
1235 print Dumper($boo), "\n";
1237 $Data::Dumper::Indent = 1; # mild pretty print
1240 $Data::Dumper::Indent = 3; # pretty print with array indices
1243 $Data::Dumper::Useqq = 1; # print strings in double quotes
1246 $Data::Dumper::Pair = " : "; # specify hash key/value separator
1251 # recursive structures
1261 print Data::Dumper->Dump([$a,$b,$c], [qw(a b c)]);
1264 $Data::Dumper::Purity = 1; # fill in the holes for eval
1265 print Data::Dumper->Dump([$a, $b], [qw(*a b)]); # print as @a
1266 print Data::Dumper->Dump([$b, $a], [qw(*b a)]); # print as %b
1269 $Data::Dumper::Deepcopy = 1; # avoid cross-refs
1270 print Data::Dumper->Dump([$b, $a], [qw(*b a)]);
1273 $Data::Dumper::Purity = 0; # avoid cross-refs
1274 print Data::Dumper->Dump([$b, $a], [qw(*b a)]);
1286 print Data::Dumper->Dump([$f], [qw(f)]);
1288 $Data::Dumper::Maxdepth = 3; # no deeper than 3 refs down
1289 print Data::Dumper->Dump([$f], [qw(f)]);
1293 # object-oriented usage
1296 $d = Data::Dumper->new([$a,$b], [qw(a b)]);
1297 $d->Seen({'*c' => $c}); # stash a ref without printing it
1300 $d->Reset->Purity(0); # empty the seen cache
1301 print join "----\n", $d->Dump;
1309 sub new { bless { state => 'awake' }, shift }
1312 print STDERR "preparing to sleep\n";
1313 $s->{state} = 'asleep';
1314 return bless $s, 'Foo::ZZZ';
1320 print STDERR "waking up\n";
1321 $s->{state} = 'awake';
1322 return bless $s, 'Foo';
1328 $b = Data::Dumper->new([$a], ['c']);
1329 $b->Freezer('Freeze');
1330 $b->Toaster('Thaw');
1334 print Data::Dumper->Dump([$d], ['d']);
1338 # symbol substitution (useful for recreating CODE refs)
1341 sub foo { print "foo speaking\n" }
1344 $d = Data::Dumper->new([\&other,$bar],['*other','bar']);
1345 $d->Seen({ '*foo' => \&foo });
1350 # sorting and filtering hash keys
1353 $Data::Dumper::Sortkeys = \&my_filter;
1354 my $foo = { map { (ord, "$_$_$_") } 'I'..'Q' };
1355 my $bar = { %$foo };
1356 my $baz = { reverse %$foo };
1357 print Dumper [ $foo, $bar, $baz ];
1361 # return an array ref containing the hash keys to dump
1362 # in the order that you want them to be dumped
1364 # Sort the keys of %$foo in reverse numeric order
1365 $hash eq $foo ? (sort {$b <=> $a} keys %$hash) :
1366 # Only dump the odd number keys of %$bar
1367 $hash eq $bar ? (grep {$_ % 2} keys %$hash) :
1368 # Sort keys in default order for all other hashes
1375 Due to limitations of Perl subroutine call semantics, you cannot pass an
1376 array or hash. Prepend it with a C<\> to pass its reference instead. This
1377 will be remedied in time, now that Perl has subroutine prototypes.
1378 For now, you need to use the extended usage form, and prepend the
1379 name with a C<*> to output it as a hash or array.
1381 C<Data::Dumper> cheats with CODE references. If a code reference is
1382 encountered in the structure being processed (and if you haven't set
1383 the C<Deparse> flag), an anonymous subroutine that
1384 contains the string '"DUMMY"' will be inserted in its place, and a warning
1385 will be printed if C<Purity> is set. You can C<eval> the result, but bear
1386 in mind that the anonymous sub that gets created is just a placeholder.
1387 Someday, perl will have a switch to cache-on-demand the string
1388 representation of a compiled piece of code, I hope. If you have prior
1389 knowledge of all the code refs that your data structures are likely
1390 to have, you can use the C<Seen> method to pre-seed the internal reference
1391 table and make the dumped output point to them, instead. See L</EXAMPLES>
1394 The C<Useqq> and C<Deparse> flags makes Dump() run slower, since the
1395 XSUB implementation does not support them.
1397 SCALAR objects have the weirdest looking C<bless> workaround.
1399 Pure Perl version of C<Data::Dumper> escapes UTF-8 strings correctly
1400 only in Perl 5.8.0 and later.
1404 Starting from Perl 5.8.1 different runs of Perl will have different
1405 ordering of hash keys. The change was done for greater security,
1406 see L<perlsec/"Algorithmic Complexity Attacks">. This means that
1407 different runs of Perl will have different Data::Dumper outputs if
1408 the data contains hashes. If you need to have identical Data::Dumper
1409 outputs from different runs of Perl, use the environment variable
1410 PERL_HASH_SEED, see L<perlrun/PERL_HASH_SEED>. Using this restores
1411 the old (platform-specific) ordering: an even prettier solution might
1412 be to use the C<Sortkeys> filter of Data::Dumper.
1416 Gurusamy Sarathy gsar@activestate.com
1418 Copyright (c) 1996-2014 Gurusamy Sarathy. All rights reserved.
1419 This program is free software; you can redistribute it and/or
1420 modify it under the same terms as Perl itself.
1424 Version 2.154 (September 18 2014)