Question

I want to be able to name methods dynamically (I would not leave it up to user input to do this, but as an example):

puts ""
foo = gets
def (whatever the user inputted for foo)
end

How can I do this?

Answer 1

You can do this using the send method to send a message to the class, using the parameter :define_method to tell it you are going to define a new method for that class.

For example, having a class Car

class Car
end

c = Car.new

A call to c.sound brings about the error

NoMethodError: undefined method `sound' for #<Car:0x29d9048>

But after defining the name of the method and sending it to the class:

input = "sound"

Car.send(:define_method, input) do
  puts "vroom!"
end

The call to c.sound now brings the output

vroom!