Metafun

A library for extending Ruby native metaprogramming capabilities

Install

gem install metafun

Usage

Delegator

Delegator delegates easily methods from a given module into a target object. The delegated methods have private access to the original module properties. Its main purpose is to easy deploy DSLs

require "metafun/delegator"

extend Metafun::Delegator

module TheModule
  @@local_var = "Hello delegation"
  def self.take_action
    @@local_var
  end
end

delegate TheModule, :take_action

puts take_action  # At this stage, this is exactly the same
                  # as calling TheModule.take_action

Why Delegator and not just include TheModule? Because for most non-trivial DSLs, you want to keep an internal state in the module object, and is not a good idea to store the internal state on Object:main. You might as well wish to disable the DSL API to stop pollution of the default namespace, and it should be possible to do that transparently.

Inspired in Sinatra’s Delegator.

Switch Maker

Switch Maker makes a friendly semantic switch out of a symbol. For example

require "metafun/switchmaker"

class Klass
  switch :cache
end

# Default is false
Klass.cache?     # > false

# This is how you set it. It accepts :on/:off, :yes/:no, 
#   true/false, 1/0...
Klass.cache :on
Klass.cache?    # > true

# ... and procs 
Klass.cache lambda { false }  
Klass.cache?    # > false

Kitchen List

Delegator should work aswell with Singletons and make-instance-and-die classes.
- Make specs instead of features
Switch Maker should accept blocks, not just procs

GPL License