Class: EasyMonads::Option::None

Inherits:
Option show all
Defined in:
lib/easy_monads/option.rb

Instance Method Summary collapse

Methods inherited from Monadic

#bind_unit, #data, #unit, unit

Constructor Details

#initialize(*args) ⇒ None

Returns a new instance of None.



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# File 'lib/easy_monads/option.rb', line 14

def initialize(*args)
  @data = nil
end

Instance Method Details

#<=>(other_monad) ⇒ Object 



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# File 'lib/easy_monads/option.rb', line 29

def <=>(other_monad)
  if self == other_monad
    0
  else
    raise RuntimeError.new("#{self.class.name} is not comparable to other types") # nil <=> ... would raise NoMethodError
  end
end

#==(other_monad) ⇒ Object 



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# File 'lib/easy_monads/option.rb', line 25

def ==(other_monad)
  other_monad.is_a? self.class
end

#bind ⇒ Object 



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# File 'lib/easy_monads/option.rb', line 18

def bind
  self
end

#defined? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/easy_monads/option.rb', line 45

def defined?
  false
end

#each ⇒ Object 



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# File 'lib/easy_monads/option.rb', line 22

def each
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/easy_monads/option.rb', line 57

def empty?
  true
end

#exists?(&pred) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/easy_monads/option.rb', line 41

def exists?(&pred)
  false
end

#get_or_else(else_val = nil) ⇒ Object 



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# File 'lib/easy_monads/option.rb', line 49

def get_or_else(else_val=nil)
  if block_given?
    yield
  else
    else_val
  end
end

#or_else ⇒ Object 



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# File 'lib/easy_monads/option.rb', line 61

def or_else
  yield
end

#size ⇒ Object 



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# File 'lib/easy_monads/option.rb', line 37

def size
  0
end