package Data::Dumper::Names; use warnings; use strict; use Data::Dumper (); use Scalar::Util 'refaddr'; use PadWalker 'peek_my'; use base 'Exporter'; our @EXPORT = qw/Dumper/; =head1 NAME Data::Dumper::Names - Dump variables with names (no source filter) =head1 VERSION Version 0.02 =cut our $VERSION = '0.02'; =head1 SYNOPSIS use Data::Dumper::Names; my $foo = 3; my @bar = qw/this that/; warn Dumper($foo, \@bar); __END__ output: $foo = 3; @bar = ( 'this', 'that' ); =head1 EXPORT Like L<Data::Dumper>, this module automatically exports C<Dumper()> unless a null import list is explicitly stated. This module should be considered ALPHA. =head1 FUNCTIONS =head2 Dumper warn Dumper($foo, \@bar); C<Dumper> returns a string like C<Dumper> but the variable names are prefixed for you. Unlike L<Data::Dumper::Simple>, arrays and hashes must be passed by reference. =cut sub Dumper { my $pad = peek_my(1); my %pad_vars; while ( my ( $var, $ref ) = each %$pad ) { # we no longer remove the '$' sigil because we don't want # "$foo = \@array" reported as "@foo". $var =~ s/^[\@\%]/*/; $pad_vars{ refaddr $ref } = $var; } my @names; my $varcount = 1; foreach (@_) { my $name; INNER: foreach ( \$_, $_ ) { no warnings 'uninitialized'; $name = $pad_vars{ refaddr $_} and last INNER; } push @names, $name; } return Data::Dumper->Dump( \@_, \@names ); } =head1 CAVEATS =head2 PadWalker This module is an alternative to L<Data::Dumper::Simple>. Many people like the aforementioned module but do not like the fact that it uses a source filter. In order to pull off the trick with this module, we use L<PadWalker>. This introduces its own set of problems, not the least of which is that L<PadWalker> uses undocumented features of the Perl internals and has an annoying tendency to break. Thus, if this module doesn't work on your machine you may have to go back to L<Data::Dumper::Simple>. =head2 References Arrays and hashes, unlike in L<Data::Dumper::Simple>, must be passed by reference. Unfortunately, this causes a problem: my $foo = \@array; warn Dumper( $foo, \@array ); Because of how pads work, there is no easy way to disambiguate between these two variables. Thus, C<Dumper> may identify them as C<$foo> or it may identify them as C<@array>. If it misidentifies them, it should at least do so consistently for the individual call to C<Dumper>. (For Perl 5.8 and after, subsequent calls to C<Dumper> may have different results in the above case. This is because of how Perl handles hash ordering). =head2 Unknown Variables The easiest way to have things "just work" is to make sure that you can see the name of the variable in the C<Dumper> call: warn Dumper($foo, \@bar); # good warn Dumper($_); # probably will get output like $VAR1 = ... warn Dumper($bar[2]); # probably will get output like $VAR1 = ... Usually the output from L<Dumper> will be something like this: $foo = 3; @bar = ( 'this', 'that' ); However, sometimes a C<$VAR1> or C<$VAR2> will creep in there. This happens if pass in anything I<but> a named variable. For example: warn Dumper( $bar[2] ); # $VAR1 = ... can't figure out the name We probably won't be able to figure out the name of the variable directly unless we took the time to walk all data structures in scope at the time C<Dumper> is called. This is an expensive proposition, so we don't do that. It's possible we I<will> be able to figure out that name, but only if the variable was assigned its value from a reference to a named variable. $bar[2] = \%foo; warn Dumper( $bar[2] ); C<Dumper>, in the above example, will identify that variable as being C<%foo>. That could be confusing if those lines are far apart. foreach ( @customer ) { print Dumper( $_ ); } It should go without saying that the above will also probably not be able to name the variables. =head1 AUTHOR Curtis "Ovid" Poe, C<< <ovid@cpan.org> >> =head1 BUGS Please report any bugs or feature requests to C<bug-data-dumper-names@rt.cpan.org>, or through the web interface at L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Data-Dumper-Names>. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes. =head1 ACKNOWLEDGEMENTS See L<Data::Dumper> and L<Data::Dumper::Simple>. Thanks to demerphq (Yves Orton) for finding a bug in how some variable names are reported. See Changes for details. =head1 COPYRIGHT & LICENSE Copyright 2005 Curtis "Ovid" Poe, all rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. =cut 1; # End of Data::Dumper::Names