Sha256: b82792691d927b5cec586ef486abcc8b4a529807ef4ba2e0ad83cd84f4ff9463
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Versions: 7
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Stored size: 1.49 KB
Contents
# = Equitable
#
# This mixin provides methods of equality based
# on a single #identity method which must return
# a list of accessors used as the identity keys.
#
# It also provides a "shortcut" for creating the
# #identity method based on given accessors and returns
# the Equitable module for inclusion.
#
# include Equitable(:a, :b)
#
# is equivalent to including a module containing:
#
# def ==(other)
# self.a == other.a && self.b == other.b
# end
#
# def eql?(other)
# self.a.eql?(other.a) && self.b.eql?(other.b)
# end
#
# def hash()
# self.a.hash ^ self.b.hash
# end
#
module Equitable
def self.identify(base, *accessors)
base.send(:define_method, :identity){ accessors }
self
end
def ==(o)
identity.all?{ |a| send(a) == o.send(a) }
end
def eql?(o)
identity.all?{ |a| send(a).eql?(o.send(a)) }
end
def hash
identity.inject(0){ |memo, a| memo ^ send(a).hash }
end
end
class Module
# This function provided a "shortcut" for creating the
# #identity method based on given accessors and returns
# the Equitable module for inclusion.
#
# include Equitable(:a, :b)
#
# is equivalent to including a module containing:
#
# def ==(other)
# self.a == other.a && self.b == other.b
# end
#
# def eql?(other)
# self.a.eql?(other.a) && self.b.eql?(other.b)
# end
#
# def hash()
# self.a.hash ^ self.b.hash
# end
#
def Equitable(*accessors)
Equitable.identify(self, *accessors)
end
end
Version data entries
7 entries across 7 versions & 3 rubygems