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NAME
Variable::Disposition - helper functions for disposing of variables
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.
Since Future 0.36, this behaviour is directly available via the
"retain" in Future method, so it is recommended to use that instead of
this function.
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.
AUTHOR
Tom Molesworth <cpan@perlsite.co.uk>
LICENSE
Copyright Tom Molesworth 2014-2015. Licensed under the same terms as
Perl itself.
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