How to allow multiple parameters to be passed into define_singleton_method

Question

I want to create a class that can add methods dynamically and allow multiple parameters.

For example:

r = Robot.new
r.learn_maneuvering('turn') { |degree| puts "turning #{degree} degrees" }
r.turn 50 # => turning 50 degrees
r.turn 50, 60 # => turning 50 degrees # => turning 60 degrees

My first attempt was this:

def learn_maneuvering(name, &block)
    define_singleton_method(name, &block) 
end

However, it only accounts for one parameter..

I then started with:

def learn_maneuvering(name, &block)
    define_singleton_method(name) do |*args|
        # to do
    end
end

I believe this will loop until all arguments are used right? Anywho, I am not sure how to pass these arguments to the given block.

Answer 1

You're close:

def learn_maneuvering(name, &block)
  define_singleton_method(name) do |*args|
    args.each do |arg|
      block.call(arg)
    end
  end
end

r = Robot.new
r.learn_maneuvering('turn') { |degree| puts "turning #{degree} degrees" }

r.turn 50, 60

prints:

turning 50 degrees
turning 60 degrees

But is this really what you want? It seems like just doing

r.turn 50
r.turn 60

makes more sense to me.