++ed by:
KES TOBYINK

2 PAUSE users

Tom Molesworth
and 1 contributors

NAME

Variable::Disposition - helper functions for disposing of variables

VERSION

version 0.004

SYNOPSIS

 use feature qw(say);
 use Variable::Disposition;
 my $x = [];
 dispose $x;
 say '$x is no longer defined';

DESCRIPTION

Provides some basic helper functions for making sure variables go away when you want them to.

Currently provides "dispose" as a default import. To avoid this:

 use Variable::Disposition ();

In addition, "retain" and "retain_future" are available as optional imports.

 use Variable::Disposition qw(dispose retain retain_future);

The :all tag can be used to import every available function:

 use Variable::Disposition qw(:all);

but it would be safer to use a version instead:

 use Variable::Disposition qw(:v1);

since these are guaranteed not to change in future.

Other functions for use with Future and IO::Async are likely to be added later.

FUNCTIONS

dispose

Undefines the given variable, then checks that the original ref was destroyed.

 my $x = [1,2,3];
 dispose $x;
 # $x is no longer defined.

This is primarily intended for cases where you no longer need a variable, and want to ensure that you haven't accidentally captured a strong reference to it elsewhere.

Note that this clears the caller's variable.

This function is defined with a prototype of ($), since it is only intended for use on scalar variables. To clear multiple variables, use a foreach loop:

 my ($x, $y, $z) = ...;
 dispose $_ for $x, $y, $z;
 is($x, undef);
 is($y, undef);
 is($z, undef);

retain

Keeps a copy of this variable until program exit or "dispose".

Returns the original variable.

retain_future

Holds a copy of the given Future until it's marked ready, then releases our copy. Does not use "dispose", since that could interfere with other callbacks attached to the Future.

Returns the original Future.

SEE ALSO

  • Devel::Refcount - assert_oneref is almost identical to this, although it doesn't clear the variable it's called on

  • Closure::Explicit - provides a sub{} wrapper that will complain if you capture a lexical without explicitly declaring that you're going to do that.

INHERITED METHODS

Exporter

as_heavy, export, export_fail, export_ok_tags, export_tags, export_to_level, import, require_version

AUTHOR

Tom Molesworth <cpan@perlsite.co.uk>

LICENSE

Copyright Tom Molesworth 2014-2015. Licensed under the same terms as Perl itself.