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package Package::Stash; # git description: 5468b00 use strict; use warnings; use 5.008001; # ABSTRACT: routines for manipulating stashes our $VERSION = '0.38'; our $IMPLEMENTATION; use Module::Implementation 0.06; BEGIN { local $ENV{PACKAGE_STASH_IMPLEMENTATION} = $IMPLEMENTATION if ( $IMPLEMENTATION and not $ENV{PACKAGE_STASH_IMPLEMENTATION} ); Module::Implementation::build_loader_sub( implementations => [ 'XS', 'PP' ], symbols => [qw( new name namespace add_symbol remove_glob has_symbol get_symbol get_or_add_symbol remove_symbol list_all_symbols get_all_symbols )], )->(); $IMPLEMENTATION = Module::Implementation::implementation_for(__PACKAGE__); } 1; __END__ =pod =encoding UTF-8 =head1 NAME Package::Stash - routines for manipulating stashes =head1 VERSION version 0.38 =head1 SYNOPSIS my $stash = Package::Stash->new('Foo'); $stash->add_symbol('%foo', {bar => 1}); # $Foo::foo{bar} == 1 $stash->has_symbol('$foo') # false my $namespace = $stash->namespace; *{ $namespace->{foo} }{HASH} # {bar => 1} =head1 DESCRIPTION Manipulating stashes (Perl's symbol tables) is occasionally necessary, but incredibly messy, and easy to get wrong. This module hides all of that behind a simple API. NOTE: Most methods in this class require a variable specification that includes a sigil. If this sigil is absent, it is assumed to represent the IO slot. Due to limitations in the typeglob API available to perl code, and to typeglob manipulation in perl being quite slow, this module provides two implementations - one in pure perl, and one using XS. The XS implementation is to be preferred for most usages; the pure perl one is provided for cases where XS modules are not a possibility. The current implementation in use can be set by setting C<$ENV{PACKAGE_STASH_IMPLEMENTATION}> or C<$Package::Stash::IMPLEMENTATION> before loading Package::Stash (with the environment variable taking precedence), otherwise, it will use the XS implementation if possible, falling back to the pure perl one. =head1 METHODS =head2 new $package_name Creates a new C<Package::Stash> object, for the package given as the only argument. =head2 name Returns the name of the package that this object represents. =head2 namespace Returns the raw stash itself. =head2 add_symbol $variable $value %opts Adds a new package symbol, for the symbol given as C<$variable>, and optionally gives it an initial value of C<$value>. C<$variable> should be the name of variable including the sigil, so Package::Stash->new('Foo')->add_symbol('%foo') will create C<%Foo::foo>. Valid options (all optional) are C<filename>, C<first_line_num>, and C<last_line_num>. C<$opts{filename}>, C<$opts{first_line_num}>, and C<$opts{last_line_num}> can be used to indicate where the symbol should be regarded as having been defined. Currently these values are only used if the symbol is a subroutine ('C<&>' sigil) and only if C<$^P & 0x10> is true, in which case the special C<%DB::sub> hash is updated to record the values of C<filename>, C<first_line_num>, and C<last_line_num> for the subroutine. If these are not passed, their values are inferred (as much as possible) from C<caller> information. This is especially useful for debuggers and profilers, which use C<%DB::sub> to determine where the source code for a subroutine can be found. See L<http://perldoc.perl.org/perldebguts.html#Debugger-Internals> for more information about C<%DB::sub>. =head2 remove_glob $name Removes all package variables with the given name, regardless of sigil. =head2 has_symbol $variable Returns whether or not the given package variable (including sigil) exists. =head2 get_symbol $variable Returns the value of the given package variable (including sigil). =head2 get_or_add_symbol $variable Like C<get_symbol>, except that it will return an empty hashref or arrayref if the variable doesn't exist. =head2 remove_symbol $variable Removes the package variable described by C<$variable> (which includes the sigil); other variables with the same name but different sigils will be untouched. =head2 list_all_symbols $type_filter Returns a list of package variable names in the package, without sigils. If a C<type_filter> is passed, it is used to select package variables of a given type, where valid types are the slots of a typeglob ('SCALAR', 'CODE', 'HASH', etc). Note that if the package contained any C<BEGIN> blocks, perl will leave an empty typeglob in the C<BEGIN> slot, so this will show up if no filter is used (and similarly for C<INIT>, C<END>, etc). =head2 get_all_symbols $type_filter Returns a hashref, keyed by the variable names in the package. If C<$type_filter> is passed, the hash will contain every variable of that type in the package as values, otherwise, it will contain the typeglobs corresponding to the variable names (basically, a clone of the stash). =head1 WORKING WITH VARIABLES It is important to note, that when working with scalar variables, the default behavior is to B<copy> values. my $stash = Package::Stash->new('Some::Namespace'); my $variable = 1; # $Some::Namespace::name is a copy of $variable $stash->add_symbol('$name', $variable); $variable++ # $Some::Namespace::name == 1 , $variable == 2 This will likely confuse people who expect it to work the same as typeglob assignment, which simply creates new references to existing variables. my $variable = 1; { no strict 'refs'; # assign $Package::Stash::name = $variable *{'Package::Stash::name'} = \$variable; } $variable++ # affects both names If this behaviour is desired when working with Package::Stash, simply pass Package::Stash a scalar ref: my $stash = Package::Stash->new('Some::Namespace'); my $variable = 1; # $Some::Namespace::name is now $variable $stash->add_symbol('$name', \$variable); $variable++ # $Some::Namespace::name == 2 , $variable == 2 This will be what you want as well if you're ever working with L<Readonly> variables: use Readonly; Readonly my $value, 'hello'; $stash->add_symbol('$name', \$value); # reference print $Some::Namespace::name; # hello # Tries to modify the read-only 'hello' and dies. $Some::Namespace::name .= " world"; $stash->add_symbol('$name', $value); # copy print $Some::Namespace::name; # hello # No problem, modifying a copy, not the original $Some::Namespace::name .= " world"; =head1 SEE ALSO =over 4 =item * L<Class::MOP::Package> This module is a factoring out of code that used to live here =back =head1 SUPPORT You can find this documentation for this module with the perldoc command. perldoc Package::Stash You can also look for information at: =over 4 =item * MetaCPAN L<https://metacpan.org/release/Package-Stash> =item * Github L<https://github.com/moose/Package-Stash> =item * RT: CPAN's request tracker L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Package-Stash> =item * CPAN Ratings L<http://cpanratings.perl.org/d/Package-Stash> =back =head1 HISTORY Based on code from L<Class::MOP::Package>, by Stevan Little and the Moose Cabal. =head1 BUGS / CAVEATS =over 4 =item * Prior to perl 5.10, scalar slots are only considered to exist if they are defined This is due to a shortcoming within perl itself. See L<perlref/Making References> point 7 for more information. =item * GLOB and FORMAT variables are not (yet) accessible through this module. =item * Also, see the BUGS section for the specific backends (L<Package::Stash::XS> and L<Package::Stash::PP>) =back Bugs may be submitted through L<the RT bug tracker|https://rt.cpan.org/Public/Dist/Display.html?Name=Package-Stash> (or L<bug-Package-Stash@rt.cpan.org|mailto:bug-Package-Stash@rt.cpan.org>). =head1 AUTHOR Jesse Luehrs <doy@tozt.net> =head1 CONTRIBUTORS =for stopwords Karen Etheridge Carlos Lima Kent Fredric Justin Hunter Christian Walde Dave Rolsky Niko Tyni Renee Tim Bunce =over 4 =item * Karen Etheridge <ether@cpan.org> =item * Carlos Lima <carlos@multi> =item * Kent Fredric <kentfredric@gmail.com> =item * Justin Hunter <justin.d.hunter@gmail.com> =item * Christian Walde <walde.christian@googlemail.com> =item * Dave Rolsky <autarch@urth.org> =item * Niko Tyni <ntyni@debian.org> =item * Renee <reb@perl-services.de> =item * Tim Bunce <Tim.Bunce@pobox.com> =back =head1 COPYRIGHT AND LICENSE This software is copyright (c) 2018 by Jesse Luehrs. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself. =cut