http://qs321.pair.com?node_id=686397

gryphon has asked for the wisdom of the Perl Monks concerning the following question:

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); }

...gets rewritten to...

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

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; }; } } } }

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?

gryphon
code('Perl') || die;