RubyModKit

RubyModKit is a transpiler tool from Ruby-like syntax script to Ruby script. The name is shorthand for ruby-modify-kit.

Install the gem and add to the application's Gemfile by executing:

$ bundle add ruby_mod_kit

If bundler is not being used to manage dependencies, install the gem by executing:

$ gem install ruby_mod_kit

RubyModKit.transpile returns transpiled script.

require "ruby_mod_kit"
eval(
  RubyModKit.transpile(<<~RBM),
    class Foo
      getter @foo: Integer
      def initialize(@foo)
      end
    end
  RBM
)
p Foo.new(1).foo # => 1

require "ruby_mod_kit/core_ext/eval" gives RubyModKit.eval.

require "ruby_mod_kit/core_ext/eval"
RubyModKit.eval(<<~RBM)
  class Foo
    getter @foo: Integer
    def initialize(@foo)
    end
  end
RBM
p Foo.new(1).foo # => 1

require "ruby_mod_kit/core_ext/load" gives RubyModKit.load and RubyModKit.require.

require "ruby_mod_kit/core_ext/load"
require "tmpdir"

script = <<~RBM
  class Foo
    getter @foo: Integer
    def initialize(@foo)
    end
  end
RBM

Dir.mktmpdir do |tmpdir|
  File.write("#{tmpdir}/some_lib.rbm", script)
  $LOAD_PATH << tmpdir
  RubyModKit.require "some_lib"
end

p Foo.new(1).foo # => 1

And require "ruby_mod_kit/core_ext" is more powerfull but dangerous. It overwrites eval, require and load.

require "ruby_mod_kit/core_ext"
eval(<<~RBM)
  class Foo
    getter @foo: Integer
    def initialize(@foo)
    end
  end
RBM
p Foo.new(1).foo # => 1

require "ruby_mod_kit/core_ext"
require "tmpdir"

script = <<~RBM
  class Foo
    getter @foo: Integer
    def initialize(@foo)
    end
  end
RBM

Dir.mktmpdir do |tmpdir|
  File.write("#{tmpdir}/some_lib.rbm", script)
  $LOAD_PATH << tmpdir
  require "some_lib"
end

p Foo.new(1).foo # => 1

You can get transpiled ruby script from .rbm file by ruby_mod_kit transpile command. transpile command outputs script to stdout by default. --output can change output target. --output=.rb is a special pattern that means "Output the original script file name with the extension changed to .rb".

These below have the same meaning: "Output ruby script to stdout".

$ ruby_mod_kit transpile path/to/script.rbm
$ ruby_mod_kit transpile --output=- path/to/script.rbm
$ ruby_mod_kit transpile --output=/dev/stdout path/to/script.rbm

These below have the same meaning: "Output ruby script to path/to/script.rb".

$ ruby_mod_kit transpile path/to/script.rbm > path/to/script.rb
$ ruby_mod_kit transpile --output=path/to/script.rb path/to/script.rbm
$ ruby_mod_kit transpile --output=.rb path/to/script.rbm

You can run transpiled ruby script by ruby_mod_kit exec command.

$ ruby_mod_kit exec path/to/script.rbm

1. Type definition
   • The deifinitions will be changed to RBS-inline annotation comments.
   • Instance variables
     • @foo: Foo -> # @rbs @foo: Foo
   • Attributes (attr_reader, attr_writer, attr_accessor)
     • attr_reader @foo: Foo -> # @rbs @foo: Foo and attr_reader :foo #: Foo
     • getter, setter, property are also available
   • Method parameters
     • def foo(Bar => bar) ... end -> # @rbs foo: Foo and def foo(bar) ... end
   • Method return values
     • def foo(bar): Foo ... end -> # @rbs return: Foo and def foo(bar) ... end
2. Instance variable parameter
   • def foo(@bar) ... end -> def foo(bar) @bar = bar ... end
3. Overloading

   • def foo(Bar => arg): void
       ...
     end
     
     def foo(Buz => arg): Buz
       ...
     end
     

     ->

     # @rbs (Bar) -> void
     #    | (Buz) -> Buz
     def foo(*args)
       case args
       in [Bar]
         foo__overload0(*args)
       in [Buz]
         foo__overload1(*args)
       end
     end
     
     # @rbs arg: Bar
     # @rbs return: void
     def foo__overload0(Bar => arg)
       ...
     end
     
     # @rbs arg: Buz
     # @rbs return: Buz
     def foo__overload1(Buz => arg)
       ...
     end
     

TODO

Bug reports and pull requests are welcome on GitHub at https://github.com/wanabe/ruby_mod_kit.

The gem is available as open source under the terms of the MIT License.