FIRST

Here's an example of a few different ways to call a method on a Ruby object.

If you're a beginner, try running the code above to watch it in action.

If you're not a beginner, go ahead and tear me a new one for whichever techniques I forgot ;)

- Pat

method invocation in ruby.rb

# Ways to invoke a method in Ruby

def demonstrate(label, &block)
  print label + ': '
  result = yield Class.new { def invoke!; :correct end }.new
  puts result == :correct ? "Pass!" : "Fail (#{result})"
end

demonstrate "Directly calling it" do |object|
  object.invoke!
end

demonstrate "Using Object#send" do |object|
  object.send :invoke!
end

demonstrate "Using Object#method, then call" do |object|
  object.method(:invoke!).call
end

demonstrate "Unbinding the method, then rebinding and calling" do |object|
  m = object.class.instance_method(:invoke!)
  m.bind(object).call
end

demonstrate "Using instance_eval" do |object|
  object.instance_eval { invoke! }
end

# Feel free to fork and tell me what I forgot.

demonstrate "Using method_missing ;-)" do |object|
  object.instance_eval "def method_missing(*args); self.invoke!; end"
  object.hello?
end

demonstrate "Using method alias ;-)" do |object|
  object.class.class_eval "alias :run! :invoke!"
  object.run!
end