A way to make DSLs for Ruby

Ruby

class DSL
  def initialize(*args, &blk);    call(*args, &blk); end
  def call(*args, &blk); instance_exec(*args, &blk); end
end

class Klass
  def foo
    print 'foo'
    DSL.new do
      def bar
        puts 'bar'
      end
      def baz
        puts 'baz'
      end
    end
  end
end

klass = Klass.new
klass.foo.bar
klass.foo.baz

class Klass
  class << self
    def foo(&blk)
      @dsl ||= DSL.new do
        def bar(&blk)
          say blk.call.to_s
        end
        def say(msg)
          puts "foo#{msg}"
        end
      end
      @dsl.instance_eval(&blk) if block_given?
      @dsl
    end
  end
end

class MyKlass < Klass
  foo do
    bar do
      'barbarbar'
    end
    
    say('mmmwoah')
  end
end