47 lines
1.1 KiB
Ruby
47 lines
1.1 KiB
Ruby
class Enum < Hash
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# Public: Initialize an enum.
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#
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# members - the array of enum members. May contain a hash of options:
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# :start - the number of first enum member. Defaults to 1.
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#
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# Examples
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#
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# FRUITS = Enum.new(:apple, :orange, :kiwi)
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def initialize(*members)
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super({})
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options = members.extract_options!
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start = options.fetch(:start) { 1 }
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update Hash[members.zip(start..members.count + start)]
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end
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# Public: Access the number/value of member.
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#
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# ids_or_value - number or value of member.
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#
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# Returns value if number was provided, and number if value was provided.
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def [](id_or_value)
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fetch(id_or_value) { key(id_or_value) }
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end
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# Public: Check if supplied member is valid.
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def valid?(member)
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has_key?(member)
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end
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# Public: Create a subset of enum, only include specified keys.
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def only(*keys)
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dup.tap do |d|
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d.keep_if { |k| keys.include?(k) }
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end
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end
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# Public: Create a subset of enum, preserve all items but specified ones.
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def except(*keys)
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dup.tap do |d|
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d.delete_if { |k| keys.include?(k) }
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end
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end
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end
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