Question

I want to change the default arguments passed to a Ruby function. For example, instead of each time writing

[1,2,3].do_stuff(:option => ' my option ')

I want to modify the defaults so that I can write

[1,2,3].do_stuff

What is the simplest, cleanest, most Ruby-like way of changing default parameters?

Answer 1

>> [1, 2, 3].do_stuff
=> Result I get
>> [1, 2, 3].do_stuff :an_option => a_value
=> Result I really want, but don't want to specify the argument

I like to use super for this. It allows us to add some functionality to the method apart from just changing default arguments:

class Array
  def do_stuff(options = {})
     # Verify if caller has not passed the option
     options[:argument_i_want_to_change] = default_value_i_want unless options.has_key? :argument_i_want_to_change
     # call super
     super
  end
end

Result:

>> [1, 2, 3].do_stuff
=> Result that I really want

UPDATE: Removed reverse_merge! dependency. (Now looking for a better alternatives to using []= method)