Module: CallChain

Defined in:
lib/callchain.rb

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.[](key) ⇒ Object 



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# File 'lib/callchain.rb', line 39

def self.[](key)
  self.bind(key)
end

.bind(method_name, *args) ⇒ Object 



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# File 'lib/callchain.rb', line 43

def self.bind(method_name, *args)
  lambda { |thing| thing.send(method_name, *args) }
end

Instance Method Details

#call(thing) ⇒ Object 



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# File 'lib/callchain.rb', line 30

def call(thing)
  return thing unless chain
  chain.each do |filter|
    thing = filter.call(thing)
    yield thing, filter if block_given?
  end
  thing
end

#chain ⇒ Object 



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# File 'lib/callchain.rb', line 26

def chain
  @chain
end

#use(*args) ⇒ Object

CallChain implementations

Individual filters do work with ::call(object)

Compose a CallChain with the ::use method

Compose a CallChain of call chains because it exports ::call(object)

Example:

Pricer = Class.new(CallChain)

class AppTierPricer < Pricer
  use PlanScoper, Quantizer, AppGrouper
  use UserGrouper
end



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# File 'lib/callchain.rb', line 21

def use(*args)
  @chain ||= []
  @chain.push(*args)
end