For a large application, configuration files become a necessity. They help flexible code be used in multiple instances across multiple modules. But they are, for the most part, only data structures, which can be a problem if the configured object is expecting another configured object.

Continue reading Using MooseX::Types to Inflate Config Values...

This month's project night focused on Joel Berger's Alien::Base module. The final bugs are either squashed or very close, and we got an introduction to how the whole thing works.

Continue reading Chicago.PM Report - Project Night: Alien::Base...

Moose is great! At its very basic, it simplifies the boilerplate required to create Perl objects immensely, providing attributes with type constraints, method modifiers for semantic enhancement, and role-based class composition for better code re-use.

Moose is built on top of Class::MOP. MOP stands for Meta-Object Protocol. A meta-object is an object that describes an object. So, each attribute and method in your class has a corresponding entry in the meta-object describing it. The meta-object is where you can find out what type constraints are on an attribute, or what methods a class has available.

Since the meta-object is a Plain Old Perl Object, we can call methods on it at runtime. Using those meta-object methods to add an attribute would modify our object, adding that attribute to the object. Using Class::MOP, we can compose classes at runtime!

Continue reading Run-time Class Composition With Moose...

This month's technical presentation at Chicago Perl Mongers was about Sean Blanton's project called App::Services. It's an interesting project that uses Bread::Board to access resources like databases, logging, ssh, and others.

Continue reading Chicago.PM Report - App::Services by Sean Blanton...

How often have I told myself, "I'll kludge this now and rewrite it later"? And how many times did I actually go back and rewrite that kludgy bit? "Too often" and "not enough". Many job postings include the phrase "update legacy applications," as a euphemism for "rewrite poorly-designed spaghetti." The Y2K problem was a huge exercise in code out-living the developer's plan, with a healthy dose of cargo-culting thrown in. Lately, I've been learning to plan for a likely possibility: My code will survive to haunt my bug lists and my resume for a long time.

Continue reading Chicago.PM - Beyond grep - Expanding the Programmer Toolset...