On Dec 1, 9:16 pm, Michael Pavling <[email protected]> wrote: > On 1 December 2011 20:57, Alexey Muranov <[email protected]> wrote: > > > I tried to replace > > > self.fixture_class_names = self.fixture_class_names.merge(class_names) > > > with > > > self.fixture_class_names.merge!(class_names) # Why does this fail? > > At a guess, I'd say because "self.fixture_class_names=" is a method > that does some setting within it, while with the other syntax, you're > trying to call a bang method on the return value of a method.
Getting very warm! self.fixture_class_names is (or at least was - haven't checked rails 3.1) a superclass_delegating_accessor. This means that when you call it on a subclass it travels up the inheritance hierarchy looking for a class where it has been set. So if we had classes A < B < C < D, and A.fixture_class_names = x then calling D.fixture_class_names checks D, then C, then B a lastly A where it stops, since a value has been defined for A. When you call C.fixture_class_names = y that doesn't change what B does (it checks B and then A), but it changes what D does (it checks D, then C and returns y). However, if you do C.fixture_class_names.merge! (without having called C.fixture_class_names=) that will change the value that 'belongs' to A, thus changing what A.fixture_class_names and what B.fixture_class_names returns Fred -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
