Module: Chainable

Included in:
Request
Defined in:
lib/source/redshift/chainable.rb

Overview

Classes including module Chainable gain the ability to cache a stack of Proc objects. These blocks of code can later be executed one at a time, in the order of their insertion.

class Foo
  include Chainable
end

foo = Foo.new
foo.chain {|x| puts "x: " + x }.chain {|y,z| puts ["y: %s","z: %s"].join("\n") % [y,z] }

foo.call_chain('called 1st')
foo.call_chain('called 2nd', 'called 2nd also')

produces:

x: called 1st
y: called 2nd
z: called 2nd also

Instance Method Summary collapse

Instance Method Details

#call_chain(*args) ⇒ Object

call-seq:

chainable.call_chain(arg, ...) -> object or false

Removes the foremost Proc from chainable’s chain and calls it, returning the result. Returns false if the chain was empty.

chainable.chain {|x,y,z| x * (y + z) }

chainable.call_chain(4,5,6)   #=> 44
chainable.call_chain          #=> false



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# File 'lib/source/redshift/chainable.rb', line 33

def call_chain(*args)
  @chain ||= []
  return `#{@chain.shift}.__block__.apply(this,args)` unless @chain.empty?
  return false
end

#chain(&block) ⇒ Object

call-seq:

chainable.chain { |arg,...| block } -> chainable

Adds block to the end of chainable’s chain, then returns chainable.

chainable.chain { puts 1; return 'called 1' }.chain { puts 2; return 'called 2' }

chainable.call_chain    #=> "called 1"
chainable.call_chain    #=> "called 2"
chainable.call_chain    #=> false

produces:

1
2



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# File 'lib/source/redshift/chainable.rb', line 55

def chain(&block)
  @chain ||= []
  @chain << block
  return self
end

#clear_chain ⇒ Object

call-seq:

chainable.clear_chain -> chainable

Returns chainable with its chain emptied.

chainable.chain { 1 + 1 }

chainable.clear_chain.call_chain    #=> false



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# File 'lib/source/redshift/chainable.rb', line 70

def clear_chain
  @chain ||= []
  @chain.clear
  return self
end