Method: MIME::Type#hash

Defined in:
lib/mime/type.rb

#hash ⇒ Object

Returns a hash based on the #simplified value.

This maintains the invariant that two #eql? instances must have the same #hash (although having the same #hash does not imply that the objects are #eql?).

To see why, suppose a MIME::Type instance a is compared to another object b, and that a.eql?(b) is true. By the definition of #eql?, we know the following:

  1. b is a MIME::Type instance itself.

  2. a == b is true.

Due to the first point, we know that b should respond to the #simplified method. Thus, per the definition of #<=>, we know that a.simplified must be equal to b.simplified, as compared by the <=> method corresponding to a.simplified.

Presumably, if a.simplified <=> b.simplified is 0, then a.simplified has the same hash as b.simplified. So we assume it is suitable for #hash to delegate to #simplified in service of the #eql? invariant.



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# File 'lib/mime/type.rb', line 266

def hash
  simplified.hash
end