Class: Null

Inherits:
Object show all
Defined in:
lib/deterministic/null.rb

Overview

The simplest NullObject there can be

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(methods) ⇒ Null

Returns a new instance of Null.



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# File 'lib/deterministic/null.rb', line 34

def initialize(methods)
  @methods = methods
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(m, *args) ⇒ Object 



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# File 'lib/deterministic/null.rb', line 47

def method_missing(m, *args)
  return self if respond_to?(m)
  super
end

Class Method Details

.==(other) ⇒ Object 



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# File 'lib/deterministic/null.rb', line 28

def ==(other)
  other.respond_to?(:null?) && other.null?
end

.instance ⇒ Object 



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# File 'lib/deterministic/null.rb', line 12

def instance
  @instance ||= new([])
end

.method_missing(m, *args) ⇒ Object 



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# File 'lib/deterministic/null.rb', line 4

def method_missing(m, *args)
  if m == :new
    super
  else
    Null.instance
  end
end

.mimic(klas) ⇒ Object 



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# File 'lib/deterministic/null.rb', line 24

def mimic(klas)
  new(klas.instance_methods(false))
end

.null? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/deterministic/null.rb', line 16

def null?
  true
end

.some? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/deterministic/null.rb', line 20

def some?
  false
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/deterministic/null.rb', line 69

def ==(other)
  other.respond_to?(:null?) && other.null?
end

#inspect ⇒ Object 



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# File 'lib/deterministic/null.rb', line 65

def inspect
  'Null'
end

#null? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/deterministic/null.rb', line 52

def null?
  true
end

#respond_to?(m) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/deterministic/null.rb', line 60

def respond_to?(m)
  return true if @methods.empty? || @methods.include?(m)
  super
end

#some? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/deterministic/null.rb', line 56

def some?
  false
end

#to_ary ⇒ Object 



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# File 'lib/deterministic/null.rb', line 43

def to_ary
  []
end

#to_str ⇒ Object

implicit conversions



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# File 'lib/deterministic/null.rb', line 39

def to_str
  ''
end