53 lines
1 KiB
Perl
53 lines
1 KiB
Perl
|
package SelectSaver;
|
||
|
|
|
||
|
|
=head1 NAME
|
||
|
|
|
||
|
|
SelectSaver - save and restore selected file handle
|
||
|
|
|
||
|
|
=head1 SYNOPSIS
|
||
|
|
|
||
|
|
use SelectSaver;
|
||
|
|
|
||
|
|
{
|
||
|
|
my $saver = new SelectSaver(FILEHANDLE);
|
||
|
|
# FILEHANDLE is selected
|
||
|
|
}
|
||
|
|
# previous handle is selected
|
||
|
|
|
||
|
|
{
|
||
|
|
my $saver = new SelectSaver;
|
||
|
|
# new handle may be selected, or not
|
||
|
|
}
|
||
|
|
# previous handle is selected
|
||
|
|
|
||
|
|
=head1 DESCRIPTION
|
||
|
|
|
||
|
|
A C<SelectSaver> object contains a reference to the file handle that
|
||
|
|
was selected when it was created. If its C<new> method gets an extra
|
||
|
|
parameter, then that parameter is selected; otherwise, the selected
|
||
|
|
file handle remains unchanged.
|
||
|
|
|
||
|
|
When a C<SelectSaver> is destroyed, it re-selects the file handle
|
||
|
|
that was selected when it was created.
|
||
|
|
|
||
|
|
=cut
|
||
|
|
|
||
|
|
require 5.000;
|
||
|
|
use Carp;
|
||
|
|
use Symbol;
|
||
|
|
|
||
|
|
sub new {
|
||
|
|
@_ >= 1 && @_ <= 2 or croak 'usage: new SelectSaver [FILEHANDLE]';
|
||
|
|
my $fh = select;
|
||
|
|
my $self = bless [$fh], $_[0];
|
||
|
|
select qualify($_[1], caller) if @_ > 1;
|
||
|
|
$self;
|
||
|
|
}
|
||
|
|
|
||
|
|
sub DESTROY {
|
||
|
|
my $this = $_[0];
|
||
|
|
select $$this[0];
|
||
|
|
}
|
||
|
|
|
||
|
|
1;
|