Editing files in a module

[throop]

Brethern,

I'm building an application, call it App. It uses a module, call it Module, which I got at CPAN. I installed Module, did a make. It's got some bugs and I want to add some functionality to it. So I'm editing files in Module, and testing with a test script that calls App, which calls Module in turn.

Every time I make a change to Module, I'm performing another make. This adds another step and another 30 sec or so to the the debug/edit/test cycle. Seems like I should be able to skip the make step while I'm testing; maybe by having something that quickly changes my PATH variable so that App executes the edited code rather than the binaries. But that seems a little kludgey and error prone. What do other do?

throop

[jettero]

Chargrill is definitely correct. I do that very thing from time to time while developing.

But, please also consider that editing the module directly may be the wrong approach — unless you intend to release patches to the module maintainer. Otherwise, the next time you install a new version of Module, you'll have to make all your changes all over again.

package BetterApproach;

use strict;
use warings;
use Module;
use base qw(Module);

sub extended_function {
    my $self = shift;

    if( $something ) {
       # new stuff
       return $new_stuff
    }

    $self->SUPER::extended_function(@_); # old stuff
}

[EvanK]

and if you can't submit your improvements to the original module's author or if your modifications dont fit with the intent of the original, rewrite the module in question under a subsequent namespace (making sure to credit the original module and author, especially if you're largely including any of their code).

ie: if the original module was App::Functionality, name your modified module App::Functionality::Extra

[chargrill]

You could just use the -I flag to perl, i.e.:

$ perl -I/path/to/edited/Module yourApp.pl

Though I don't recall off the top of my head if that puts the path/to/edited/Module at the top of @INC or not ... but surely a trip to perlrun could clear that up for you.

[throop]

Brethern,

Thanks for the helpful replies. It took me a little while to interpret some of it correctly, so I herein post my trouble for anybody else who is trying to do the same.

The -I suggestion was very helpful, but I was not having any joy trying to give it two directories to add to @INC. The Camel doc told me that it was preferable to use lib in the script instead of -I in the call to Perl. Did that. I am editing Grapher.pm in the Module::Dependency CPAN module. I have it sitting in /home/throop/perl/Module-Dependency-1.86/lib/Module/Dependency/Grapher.pm Naively, I entered the code:

use lib qw(/home/throop/perl/Module-Dependency-1.86/lib/Module/Depende
+ncy);

which didn't work. The Module/Dependency in the string was the culprit. Perl went looking for /home/throop/perl/Module-Dependency-1.86/lib/Module/Dependency/Module/Dependency/Grapher.pm, didn't find it, quit. What worked was

use lib qw(/home/throop/perl/Module-Dependency-1.86/lib);

letting Perl transmogrify Module::Dependency::Grapher into Module/Dependency/Grapher.pm

As for the wisdom of modifying CPAN module code — point taken. I wrote the maintainer with some queries and he noted that the particular section of the code that I need hasn't received much loving for a long time; asked me to update it. I may do that; I'm having discussions with my employer. I know about forgiveness and permission but I'm wish to be careful and scrupulous.

throop