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Contents
module RGen
module MetamodelBuilder
module DataTypes
# An enum object is used to describe possible attribute values within a
# MetamodelBuilder attribute definition. An attribute defined this way can only
# take the values specified when creating the Enum object.
# Literal values can only be symbols or true or false.
# Optionally a name may be specified for the enum object.
#
# Examples:
#
# Enum.new(:name => "AnimalEnum", :literals => [:cat, :dog])
# Enum.new(:literals => [:cat, :dog])
# Enum.new([:cat, :dog])
#
class Enum
attr_reader :name, :literals
# Creates a new named enum type object consisting of the elements passed as arguments.
def initialize(params)
if params.is_a?(Array)
@literals = params
@name = "anonymous"
elsif params.is_a?(Hash)
raise StandardError.new("Hash entry :literals is missing") unless params[:literals]
@literals = params[:literals]
@name = params[:name] || "anonymous"
else
raise StandardError.new("Pass an Array or a Hash")
end
end
# This method can be used to check if an object can be used as value for
# variables having this enum object as type.
def validLiteral?(l)
literals.include?(l)
end
def literals_as_strings
literals.collect do |l|
if l.is_a?(Symbol)
":"+l.to_s
elsif l.is_a?(TrueClass) || l.is_a?(FalseClass)
l.to_s
else
raise StandardError.new("Literal values can only be symbols or true/false")
end
end
end
def to_s # :nodoc:
name
end
end
# Boolean is a predefined enum object having Ruby's true and false singletons
# as possible values.
Boolean = Enum.new(:name => "Boolean", :literals => [true, false])
end
end
end
Version data entries
10 entries across 10 versions & 1 rubygems