There’s been a lot of talk about method_missing lately. Let’s do a little example that leverages this freaky but neat little method in our quest to bend Rails to our will. The following code is a handy trick that lets you access key values in a Hash as regular class methods.
class Hash def method_missing(method, *params) method = method.to_sym return self[method] if self.keys.collect(&:to_sym).include?(method) super end end
If you have a key called :name, then my_hash[:name] and my_hash.name will now give the same result. If you call some key that doesn’t exist, then the super call tells Object to throw a generic NoMethodError. Neat, no?
P.S. the collect(&:to_sym) shortcut used above actually evaluates to collect{|x| x.to_sym} in Rails. This functionality is not available in Ruby, but it can easily be replicated by overriding the Symbol class, like so:
class Symbol def to_proc(*args) Proc.new { |*args| args.shift.__send__(self, *args) } end end
Bending Ruby will be a series of posts that will build on one another.
