From: jason@... (Jason Voegele)
Date: 2001-11-02T01:18:35+09:00
Subject: [ruby-talk:24095] C-like enum

For those of you who want a simple "enum" feature for Ruby (a-la C), try this:

module Kernel
    # simple (sequential) enumerated values
    def enum(*symbols, &init_val)
        i = 0
        if block_given?
            i = init_val.call
        end
        symbols.each do |symbol|
            module_eval("#{symbol} = i")
            i += 1
        end
    end

    # enumerated values suitable for bitwise OR-ing
    def enum2(*symbols)
        i = 1
        count = 0
        symbols.each do |symbol|
            module_eval("#{symbol} = i")
            count += 1
            i = 2**count
        end
    end
end

class EnumTest

    enum(:ONE, :TWO, :THREE) {1}

    enum2 :READ, :WRITE, :EXECUTE

    def initialize
        puts ONE
        puts TWO
        puts THREE
        puts READ
        puts WRITE
        puts EXECUTE
    end
end

EnumTest.new

Hope you find this useful.

Jason Voegele