class MyClass
include Enums
enum foo: [:x, :y]
endme = MyClass.new
me.foo # nil
me.foo_i # nil
me.foo = :y
me.foo # :y
me.foo_i # 1
me.foo = :z # error!
Last active
January 3, 2019 01:03
-
-
Save mvalipour/5106d91de8bb156d3e550054d9fe4586 to your computer and use it in GitHub Desktop.
A minimalistic enums implementation in ruby
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| module Enums | |
| def self.included(base) | |
| base.extend(ClassMethods) | |
| end | |
| module ClassMethods | |
| def enum(maps) | |
| maps.each do |key, options| | |
| attr_reader "#{key}_i" | |
| define_method("#{key}=") do |value| | |
| unless (index = options.find_index(value)) | |
| raise "Invalid value '#{value}' for #{key}" | |
| end | |
| instance_variable_set("@#{key}_i", index) | |
| end | |
| define_method(key) do | |
| return unless (index = send("#{key}_i")) | |
| options[index] | |
| end | |
| end | |
| end | |
| end | |
| end |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment