open STDOUT to a subroutine reference?

[jandrew]

Hello all,

Whenever possible I use a subset of a project that I am working on to learn some new element of perl. This winds up being a really great way to improve my perl-Foo but can on occaision lead to a massive time sink with no actual result.

Currently I have hit an impasse on my latest 'I wonder if I can do that' and I would like some feedback if possible. I'm trying to open STDOUT to a subroutine reference and I'm intrigued by the fact that it doesn't die but it also doesn't behave the way I had hoped. I also wonder if it's significant that the variable is still a CODE ref even after I use it in the open statement.

use Modern::Perl;
print "Hello World 1\n";
my $sub_ref = sub{ warn join( ' ', @_ ) . 
                " - this is really bad" };
open( STDOUT, ">>", $sub_ref ) or 
        die "open failed: " . $!;
print "Hello World 2";
warn ref $sub_ref;

results in the output

Hello World 1
CODE at CodeTest.pl line 8.

I would like to get

Hello World 1
Hello World 2 - this is really bad at CodeTest.pl line 3
CODE at CodeTest.pl line 8.

Any help or even don't go there's with an explanation would be helpful. I am aware of tee and pipe and although tie seemed intriguing I couldn't get it to tie \*STDOUT to a CODE ref at all.

[tobyink]

IO::Callback to the rescue! (It's a module so cool, I couldn't stand to see it languishing unmaintained on CPAN, so I took over maintenance.)

use IO::Callback;

# Here's the coderef
my $code = sub {
    my $str = shift;
    print STDERR "This is really bad: $str";
};

# Turn it into a filehandle opened in write mode
my $fh = IO::Callback->new('>', $code);

# Select that filehandle (makes it the default for print, say, etc).
select($fh);

# Print something - it gets passed to the coderef!
print "Hello World\n";

[jandrew]

tobyink++ yet again you have provided the answer.

Thank you.