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Vincent Pit
and 1 contributors

NAME

Variable::Temp - Temporarily change the value of a variable.

VERSION

Version 0.04

SYNOPSIS

    use Variable::Temp 'temp';

    my $x = 1;
    say $x; # 1
    {
     temp $x = 2;
     say $x; # 2
    }
    say $x; # 1

DESCRIPTION

This module provides an utility routine that can be used to temporarily change the value of a scalar, array or hash variable, until the end of the current scope is reached where the original value of the variable is restored. It is similar to local, except that it can be applied onto lexicals as well as globals, and that it replaces values by copying the new value into the container variable instead of by aliasing.

FUNCTIONS

temp

    temp $var;
    temp $var = $value;

    temp @var;
    temp @var = \@value;

    temp %var;
    temp %var = \%value;

Temporarily replaces the value of the lexical or global variable $var by $value (respectively @var by @value, %var by %value), or by undef if $value is omitted (respectively empties @var and %var if the second argument is omitted), until the end of the current scope. Any subsequent assignments to this variable in the current (or any inferior) scope will not affect the original value which will be restored into the variable at scope end. Several temp calls can be made onto the same variable, and the restore are processed in reverse order.

Note that destructors associated with the variable will not be called when temp sets the temporary value, but only at the natural end of life of the variable. They will trigger after any destructor associated with the replacement value.

Due to a shortcoming in the handling of the \$ prototype, which was addressed in perl 5.14, the pseudo-statement temp $var = $value will cause compilation errors on perl 5.12.x and below. If you want your code to run on these versions of perl, you are encouraged to use "set_temp" instead.

set_temp

    set_temp $var;
    set_temp $var => $value;

    set_temp @var;
    set_temp @var => \@value;

    set_temp %var;
    set_temp %var => \%value;

A non-lvalue variant of "temp" that can be used with any version of perl.

EXPORT

The functions "temp" and "set_temp" are only exported on request by specifying their names in the module import list.

DEPENDENCIES

perl 5.6.

Exporter (core since perl 5).

Scope::Upper.

Variable::Magic 0.51.

SEE ALSO

Scope::Upper.

"local" in perlfunc.

AUTHOR

Vincent Pit, <perl at profvince.com>, http://www.profvince.com.

You can contact me by mail or on irc.perl.org (vincent).

BUGS

Please report any bugs or feature requests to bug-variable-temp at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Variable-Temp. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc Variable::Temp

COPYRIGHT & LICENSE

Copyright 2015,2017 Vincent Pit, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.