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# frozen_string_literal: true
require 'eac_ruby_utils/inflector'
module EacRubyUtils
# Similar to Java's enum type (https://docs.oracle.com/javase/tutorial/java/javaOO/enum.html).
class Enum
class << self
def enum(key, *args, &block)
value = Value.new(self, key, args, &block)
raise ::ArgumentError, "#{self} already has a value with key=#{value.key}" if
value_set.include?(value)
value_set << value.apply
self
end
def values
value_set.map(&:value)
end
private
def value_set
@value_set ||= []
end
end
attr_reader :key
protected
def initialize(key)
@key = key
end
class Value
include ::Comparable
attr_reader :klass, :key, :args, :block
def initialize(klass, key, args, &block)
@klass = klass
@key = ::EacRubyUtils::Inflector.variableize(key.to_s).to_sym
@args = args
@block = block
end
def <=>(other)
key <=> other.key
end
def apply
define_constant
define_class_method
self
end
# @return [String]
def class_method_name
key.to_s
end
# @return [String]
def constant_name
class_method_name.upcase
end
def value
@value ||= uncached_value
end
private
def define_class_method
the_value = self
klass.define_singleton_method(class_method_name) { the_value.value }
end
def define_constant
klass.const_set(constant_name, value)
end
def uncached_value
klass.new(key, *value_args)
end
def value_args
r = if block
block.call
elsif args.count == 1 && args.first.is_a?(::Enumerable)
args.first
else
args
end
r.is_a?(::Enumerable) ? r : [r]
end
end
end
end
Version data entries
190 entries across 190 versions & 3 rubygems