http://www.perlmonks.org?node_id=27446


in reply to RE: RE: Filehandle Filter
in thread Filehandle Filter

Okay, I got rid of the hash and used blessed typeglobs, just because I'm that kinda guy and I want the approval of heroes like chip and merlyn and Damian.
package Filter::Handle; use strict; use vars qw/@ISA/; use Tie::Handle; @ISA = qw/Tie::Handle/; sub TIEHANDLE { my $class = shift; my $fh = shift; bless $fh, $class; } sub new { my $class = shift; my $fh = shift; my $sub = shift; *fh = $sub; tie *{$fh}, __PACKAGE__, $fh; bless $fh, $class; } sub DESTROY { my $self = shift; my $fh = *{ $self }; { local $^W = 0; untie *{$fh} } } sub PRINT { my $self = shift; my $fh = *$self; my $code = *fh{CODE}; die "No output handler installed" unless defined $code; print $fh $code->(@_); } sub CLOSE { }
You can pass an anonymous sub or a sub ref to the constructor:
#!/usr/bin/perl -w use strict; use Filter::Handle; local *OUTPUT; open(OUTPUT, ">handle.txt") || die "Can't open: $!"; my $fh = \*OUTPUT; my $f = Filter::Handle->new($fh, sub { my($file, $line) = (caller(1))[1,2]; return sprintf "%s:%d - %s\n", $file, $line, @_; }); print OUTPUT "Foo"; print OUTPUT "Bar";
Yeah, that's pretty evil. But hey, why not?