Class: Naught::ConversionsModule

Inherits:
Module
  • Object
show all
Defined in:
lib/naught/null_class_builder/conversions_module.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(null_class, null_equivs) ⇒ ConversionsModule

Returns a new instance of ConversionsModule.



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# File 'lib/naught/null_class_builder/conversions_module.rb', line 6

def initialize(null_class, null_equivs)
  @null_class  = null_class
  @null_equivs = null_equivs
  mod          = self
  super() do
    %w[Null Maybe Just Actual].each do |method_name|
      define_method(method_name, &mod.method(method_name))
    end
  end
end

Instance Attribute Details

#null_class ⇒ Object (readonly)

Returns the value of attribute null_class.



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# File 'lib/naught/null_class_builder/conversions_module.rb', line 3

def null_class
  @null_class
end

#null_equivs ⇒ Object (readonly)

Returns the value of attribute null_equivs.



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# File 'lib/naught/null_class_builder/conversions_module.rb', line 4

def null_equivs
  @null_equivs
end

Instance Method Details

#Actual(object = nil, &block) ⇒ Object 



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# File 'lib/naught/null_class_builder/conversions_module.rb', line 47

def Actual(object=nil, &block)
  object = block ? block.call : object
  case object
  when NullObjectTag then nil
  else
    object
  end
end

#Just(object = nil, &block) ⇒ Object 



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# File 'lib/naught/null_class_builder/conversions_module.rb', line 37

def Just(object=nil, &block)
  object = block ? block.call : object
  case object
  when NullObjectTag, *null_equivs
    raise ArgumentError, "Null value: #{object.inspect}"
  else
    object
  end
end

#Maybe(object = nil, &block) ⇒ Object 



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# File 'lib/naught/null_class_builder/conversions_module.rb', line 26

def Maybe(object=nil, &block)
  object = block ? block.call : object
  case object
  when NullObjectTag then object
  when *null_equivs
    null_class.get(caller: caller(1))
  else
    object
  end
end

#Null(object = :nothing_passed) ⇒ Object 



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# File 'lib/naught/null_class_builder/conversions_module.rb', line 17

def Null(object=:nothing_passed)
  case object
  when NullObjectTag then object
  when :nothing_passed, *null_equivs
    null_class.get(caller: caller(1))
  else raise ArgumentError, "#{object.inspect} is not null!"
  end
end