Module: AttrComparable::ClassMethods

Defined in:
lib/attr_comparable.rb

Instance Method Summary collapse

Instance Method Details

#attr_compare(*attributes) ⇒ Object 



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# File 'lib/attr_comparable.rb', line 28

def attr_compare(*attributes)
  attributes = attributes.flatten
  class_eval "def <=>(rhs)\n\#{attributes.map do |attribute|\n\"self.class.compare_with_nil(self.\#{attribute}, rhs.\#{attribute})\"\nend.join(\" || \")\n} || 0\nend\n"
end

#compare_with_nil(left, right) ⇒ Object

like <=> but handles nil values when equal, returns nil rather than 0 so the caller can || together



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# File 'lib/attr_comparable.rb', line 14

def compare_with_nil(left, right)
  if left.nil?
    if right.nil?
      nil
    else
      -1
    end
  elsif right.nil?
    1
  else
    (left <=> right).nonzero?
  end
end