NOTE: This gem is not stable yet. Use at your own risk.
Easily define enums in Ruby that aren't just symbols. Your enums can have associated values and methods. Imagine if Ruby had Rust's or Swift's enums.
Since this isn't published on rubygems.org yet, you'll have to
- Download the repo
bundle installrake install
Basic API for defining enums:
module Colors
extend YaEnum
variant :Red do
def rgb
[255, 0, 0]
end
end
variant :Blue do
def rgb
[0, 0, 255]
end
end
end
p Colors::Red.rgb # => [255, 0, 0]
p Colors::Blue.rgb # => [0, 0, 255]You can also define methods outside the variants, which will be inherited by each variant
module Colors
extend YaEnum
variant :Red do
def rgb
[max, 0, 0]
end
end
variant :Blue do
def rgb
[0, 0, max]
end
end
def max
255
end
end
p Colors::Blue.rgb # => [0, 0, 255]
p Colors::Blue.max # 255Enums can also have associated values:
module Colors
extend YaEnum
variant :Red, [:max] do
def rgb
[max, 0, 0]
end
end
variant :Blue, [:max] do
def rgb
[0, 0, max]
end
end
end
p Colors::Red.new(max: 255).rgb # => [255, 0, 0]
p Colors::Blue.new(max: 255).rgb # => [0, 0, 255]Enums can also be used in case statements:
module Colors
extend YaEnum
variant :Red, [:max]
variant :Blue, [:max]
end
color = Colors::Red.new(max: 255)
case color
when Colors::Red
puts "red!"
when Colors::Blue
puts "blue!"
else
raise "Unknown case"
end # => red!If you forget to implement a method for a variant you'll get an exception:
module Colors
extend YaEnum
variant :Red, [:max] do
def rgb
[max, 0, 0]
end
end
variant :Blue, [:max] do
end
end
# Traceback (most recent call last):
# 5: from readme.rb:3:in `<main>'
# 4: from readme.rb:12:in `<module:Colors>'
# 3: from .../ya_enum/lib/ya_enum.rb:35:in `variant'
# 2: from .../ya_enum/lib/ya_enum.rb:49:in `ensure_all_methods_defined_for_each_variant!'
# 1: from .../ya_enum/lib/ya_enum.rb:49:in `each'
# .../ya_enum/lib/ya_enum.rb:54:in `block in ensure_all_methods_defined_for_each_variant!': Variant Blue is missing the following methods: (YaEnum::MissingMethods)
# rgbYou can also use the .case method to ensure you're handling all cases
module Colors
extend YaEnum
variant :Red
variant :Blue
end
color = Colors::Red
Colors.case(color) do |c|
c.on(Colors::Red) do
puts "red!"
end
c.on(Colors::Blue) do
puts "blue!"
end
endThis is different from a normal case statement because you'll get an YaEnum::Matcher::NonExhaustiveMatch exception if you forget to handle a case:
module Colors
extend YaEnum
variant :Red
variant :Blue
end
color = Colors::Red
Colors.case(color) do |c|
c.on(Colors::Red) do
puts "red!"
end
end
# Traceback (most recent call last):
# 5: from readme.rb:12:in `<main>'
# 4: from .../ya_enum/lib/ya_enum.rb:42:in `case'
# 3: from .../ya_enum/lib/ya_enum/matcher.rb:13:in `match_on'
# 2: from .../ya_enum/lib/ya_enum/matcher.rb:31:in `ensure_all_variants_handled!'
# 1: from .../ya_enum/lib/ya_enum/matcher.rb:31:in `each'
# .../ya_enum/lib/ya_enum/matcher.rb:33:in `block in ensure_all_variants_handled!': Variant Blue is not handled (YaEnum::Matcher::NonExhaustiveMatch)After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.
Bug reports and pull requests are welcome on GitHub at https://github.com/tonsser/ya_enum