Module: Rpub::SubclassTracker

Includes:
Enumerable
Included in:
Commands::Base
Defined in:
lib/rpub/subclass_tracker.rb

Overview

Add tracking of subclasses to an existing class by extending it with SubclassTracker.

This allows you to set an identifier in a subclass using the identifier macro, and find subclasses based on that value.

Example:

class ParentClass
  extend SubclassTracker
end

class ChildClass < ParentClass
  identifier 'foo'
end

ParentClass.matching('foo') # => ChildClass
ParentClass.matching('bar') # => raises SubclassTracker::NoSuchSubclass

Note that you don’t HAVE to set an identifier. If you don’t, your child class will never be found by #matching.

Defined Under Namespace

Classes: NoSuchSubclass

Instance Method Summary collapse

Instance Method Details

#each ⇒ Object 



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# File 'lib/rpub/subclass_tracker.rb', line 42

def each
  @subclasses ||= []
  @subclasses.each { |subclass| yield subclass }
end

#identifier(id = nil) ⇒ Object

Set or return the identifier for this class.



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# File 'lib/rpub/subclass_tracker.rb', line 31

def identifier(id = nil)
  return @identifier if id.nil?
  @identifier = id
end

#inherited(child) ⇒ Object 



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# File 'lib/rpub/subclass_tracker.rb', line 36

def inherited(child)
  @subclasses ||= []
  @subclasses << child
  super
end

#matching(identifier) ⇒ Object 



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# File 'lib/rpub/subclass_tracker.rb', line 47

def matching(identifier)
  find { |subclass| subclass.identifier === identifier } or raise NoSuchSubclass, identifier
end