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| module Comparable |
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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
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include Comparable
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attr :str
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def <=>(anOther)
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str.size <=> anOther.str.size
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end
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def initialize(str)
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@str = str
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end
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def inspect
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@str
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end
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end
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s1 = SizeMatters.new("Z")
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s2 = SizeMatters.new("YY")
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s3 = SizeMatters.new("XXX")
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s4 = SizeMatters.new("WWWW")
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s5 = SizeMatters.new("VVVVV")
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s1 < s2
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true
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s4.between?(s1, s3)
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false
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s4.between?(s3, s5)
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true
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[ s3, s2, s5, s4, s1 ].sort
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[Z, YY, XXX, WWWW, VVVVV]
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| instance methods | ||
| Comparisons |
anObject < otherObject -> true or false
anObject <= otherObject -> true or false
anObject == otherObject -> true or false
anObject >= otherObject -> true or false
anObject > otherObject -> true or false
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Compares two objects based on the receiver's <=> method.
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| between? |
anObject.between?( min, max )
-> true or false
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Returns false if anObject <=> min is less than
zero or if anObject <=> max is greater than zero,
true otherwise.
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