carldr.com

# extract_options!

The (old) “standard” way of extracting an optional options hash passed as the last parameter of a method call :

def add_food( *args )
  options = args.last.is_a?( Hash ) ? args.pop : {}
  puts args.inspect
  puts options.inspect
end
add_food( "cheese", :edible => true, :drinkable => false )
=> "cheese" 
=> {:edible=>true, :drinkable=>false }

This is something I’m seemingly doing more and more, and let’s face it – It’s ugly.

However, as of changeset 7217 (and the original ticket) of Rails, a method has been added to Array encapulate this. You can now do :

require 'active_support'
def add_food( *args )
  options = args.extract_options!
  puts args.inspect
  puts options.inspect
end
add_food( "cheese", :edible => true, :drinkable => false )
=> "cheese" 
=> {:edible=>true, :drinkable=>false}

Such a simple addition, it’s hard to believe there wasn’t already a method to do this.

Update: And yes, I realise my examples above are crap – Hopefully you can see what’s happening though.