Module: Comparable

The Comparable mixin is used by classes whose objects may be ordered. The class must define the <=> operator, which compares the receiver against another object, returning -1, 0, or +1 depending on whether the receiver is less than, equal to, or greater than the other object. Comparable uses <=> to implement the conventional comparison operators (<, <=, ==, >=, and >) and the method between?.

class SizeMatters
  include Comparable
  attr :str
  def <=>(anOther)
    str.size <=> anOther.str.size
  end
  def initialize(str)
    @str = str
  end
  def inspect
    @str
  end
end

s1 = SizeMatters.new("Z")
s2 = SizeMatters.new("YY")
s3 = SizeMatters.new("XXX")
s4 = SizeMatters.new("WWWW")
s5 = SizeMatters.new("VVVVV")

s1 < s2                       #=> true
s4.between?(s1, s3)           #=> false
s4.between?(s3, s5)           #=> true
[ s3, s2, s5, s4, s1 ].sort   #=> [Z, YY, XXX, WWWW, VVVVV]

Public Methods
<	Compares two objects based on the receiver’s `<=>` method, returning true if it returns -1.
<=	Compares two objects based on the receiver’s `<=>` method, returning true if it returns -1 or 0.
==	Compares two objects based on the receiver’s `<=>` method, returning true if it returns 0. Also returns true if obj and other are the same object.
>	Compares two objects based on the receiver’s `<=>` method, returning true if it returns 1.
>=	Compares two objects based on the receiver’s `<=>` method, returning true if it returns 0 or 1.
between?	Returns `false` if obj `<=>` min is less than zero or if anObject `<=>` max is greater than zero, `true` otherwise.

Comparable

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