class Array
  def only
    length == 1 ? first : self
  end
end

class ProcClass
  def initialize(&block)
    @block = block
  end

  def to_class
    ClassBuilder.new(&@block)
  end

  private

  class ClassBuilder
    def initialize(&block)
      @block = block
    end

    def new(*args, &block)
      instance = InstanceBuilder.new
      static   = StaticBuilder.new(self)

      @block.call(instance, static)

      if instance.respond_to?(:Init)
        instance.Init(*args, &block)
      end

      instance
    end

    def inspect
      "ProcClass"
    end
    alias inspect to_s

    def class
      Class
    end
  end

  class InstanceBuilder
    def initialize
      @hash = {}
    end

    def __key?(key)
      @hash.key?(key.to_s)
    end
    alias respond_to? __key?

    def __hash
      @hash
    end
    alias method_table __hash

    def method_missing(name, *values, &block)
      name = name.to_s

      if name.end_with?('=')
        @hash[name.tr('=', '')] = values.only
      else
        result = @hash[name]
        return unless result

        if result.is_a?(Proc)
          result.call(*values, &block)
        else
          result
        end
      end
    end
  end

  class StaticBuilder < BasicObject
    def initialize(class_builder)
      @class_builder = class_builder
    end

    def method_missing(name, procc)
      name = name.to_s.tr('=', '')
      @class_builder.define_singleton_method(name, &procc)
    end
  end
end

def klass!(&block)
  ProcClass.new(&block).to_class
end

MyClass = klass! { |this, static|
  static.X = proc {
    1
  }

  this.Init = proc { |name|
    this.Set_Name(name)
  }

  this.Set_Name = proc { |name|
    this.name = name
  }
}

p MyClass.new('Dakota').name
p MyClass.X