Greetings all,

I've got an application with a handful of modules in an inheritance tree, with a single super-class above it all from which the other modules eventually inherit, directly or indirectly. What I'd like to do is add in every sub a call to a logging method without having lots of duplicated code. So I thought what might work is to use the super-class's import() to find all the subroutines within the package and rewrite them, adding the call. I've failed miserably.

Ultimately, here's what I'd like to have happen:

sub something {
    my ( $self, $param ) = @_;
    return _stuff($param);
}
[download]

...gets rewritten to...

sub something {
    log_msg('starting sub');
    my ( $self, $param ) = @_;
    return _stuff($param);
}
[download]

So far, this is what I've come up with (but I can't get it to work). This is import() from the super-class:

sub import {
    my $package_name = shift;

    if (
        $package_name !~ /^Application::Stuff_I_Dont_Want_To_Alter::/
    ) {
        no strict 'refs';
        no warnings 'redefine';

        foreach ( keys %{ *{ $package_name . '::' } } ) {
            next if (
                $_ !~ /[a-z]/ or
                $_ =~ /::$/ or
                $_ eq 'isa' or
                $_ eq 'import'
            );

            if ( *{ $package_name, '::', $_ }{'CODE'} ) {
                my $code = do{
                    *{ $package_name, '::', $_ }{'CODE'};
                };

                *{ $package_name, '::', $_ } = sub {
                    warn "BEGIN sub block...\n";
                    my @rv = $code->(@_);
                    warn "END sub block...\n";
                    return @rv;
                };
            }
        }
    }
}
[download]

So part of the problem (apart from my inability to get this to work at all) is that the warn statements are outside the $code->() call. Is there a way I can append them inside the subroutine itself?