Question

Let’s say I want a method which will be called like this:

 tiger = create_tiger( :num_stripes => 12, :max_speed => 43.2 )
 tiger.num_stripes # will be 12

where some of the options have default values:

 tiger = create_tiger( :max_speed => 43.2 )
 tiger.num_stripes # will have some default value

what’s a nice idiomatic ruby way of implementing that defaulting behaviour in the method implementation?

Answer 1

If you’re using Rails (not just plain Ruby), a slightly shorter method is

def foo(options = {})
  options.reverse_merge! { ... defaults ... }
end

This has the added advantage of allowing you to do multiple lines a tad bit more cleanly:

def foo(options = {})
  options.reverse_merge!(
    :some_default => true,
    :other_default => 5
  )
end