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Size: 728 Bytes
Versions: 31
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Contents
##
# Allows attributes to be declared as lazy, meaning that they won't be
# computed until they are asked for.
#
# Works by delegating each lazy_reader to a cached lazy_source method.
#
# class Person
# lazy_reader :eyes
#
# def lazy_source
# OpenStruct.new(:eyes => 2)
# end
# end
#
# >> Person.new.eyes
# => 2
#
module Lazy
def lazy_reader(*args)
args.each do |arg|
ivar = "@#{arg}"
define_method(arg) do
if instance_variable_defined?(ivar)
val = instance_variable_get(ivar)
return val if val
end
instance_variable_set(ivar, (@lazy_source ||= lazy_source).send(arg))
end
end
end
end
Object.extend Lazy unless Object.ancestors.include? Lazy
Version data entries
31 entries across 31 versions & 13 rubygems