diff options
Diffstat (limited to 'Master/perltl/lib/SelectSaver.pm')
-rw-r--r-- | Master/perltl/lib/SelectSaver.pm | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/Master/perltl/lib/SelectSaver.pm b/Master/perltl/lib/SelectSaver.pm new file mode 100644 index 00000000000..08104f47d4c --- /dev/null +++ b/Master/perltl/lib/SelectSaver.pm @@ -0,0 +1,54 @@ +package SelectSaver; + +our $VERSION = '1.00'; + +=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; |