Move Processor Behavior to a Module

[teliosdev]

I don't know if this is an acceptable pull request because of the lack of a contributing file, but I wanted to modify the way the processor worked a little bit. My primary concern with the processor was that it was a class - you were forced to subclass the processor, which, in my mind, made no sense. The processor didn't make any sense as a class, mainly because of these reasons:

1. It violates the Liskov substitution principle, because the processor should never be instantiated within a program (it is always subclassed).
2. It's an anti-pattern. Specifically, it's the framework superclass anti-pattern.
3. It violates the Composite resuse principle, or "composition over inheritance."

These are made complicated by the fact that the behaviors of the processor are essentially private. the #process and #process_all methods are not meant to be public, so describing how the processor "behaves" publicly is awkward.

However, in interest of compatibility, I've kept the processor as a class, and instead defined AST::Processor::Module, which contains the previous processor behavior. AST::Processor is now just a class that includes AST::Processor::Module.

Anyway, nice library. Cheers!

[teliosdev]

It looks like the build is failing for reasons independent to this change.

[whitequark]

Yes, you have a point. Two nits:

• The docs should also move to AST::Processor::Module. Maybe also deprecate AST::Processor entirely, why not.
• I don't like the name Module. That just describes how it's implemented, not what it does. Maybe Mixin or Behavior.

[teliosdev]

I agree with both points; how should I deprecate AST::Processor?

[whitequark]

# @deprecated message...

[teliosdev]

Done.

[whitequark]

Process is a really awful name. It's a verb, and a module is a thing.

[teliosdev]

I have to say, I'm extremely happy with the amount of documentation that you provide in your library.

[whitequark]

Renamed to Mixin instead and merged. Thanks!

[teliosdev]

What version can I expect to find this in?

[whitequark]

Released 2.1.0.

[teliosdev]

Awesome, thanks!