Ruby on Rails

John Merlino wrote in post #1077564:
> For the method invocation expression o.m, Ruby performs name
> resolution with the following steps: 1) first, it checks the
> eigenclass of o for singleton methods named m. 2) If no method m is
> found in the eigenclass, Ruby searches the class of the o for an
> instance method named m. 3) If no method m is found in the class, Ruby
> searches the instance methods of any modules included by the class of
> o. If that class includes more than one module, then they are searched
> in the reveerse of the order in which they wre included. That is, the
> most recently included module is searched first. If no instance method
> m is found in the class of o or in its modules, then the search moves
> up the inheirtance hierarchy to the superclass. Steps 2 and 3 are
> repeated for each class in the inheritance heirarchy until each
> ancestor class and its included modules have been searched. If no
> method named m is found after completing the search, then a method
> named method_missing is invoked instead. In order to find an
> appropriate definition of this method, the name resolution algorithm
> starts over at step 1. The kernel module provides a default
> implementation of method_missing, so this second pass of name
> resolution is guaranteed to succeed.
>
> Notice the part "Steps 2 and 3 are repeated for each class in the
> inheritance heirarchy..."
>
> What if the superclass has an eigenclass method? Why doesn't it repeat
> Step 1?

I'm not sure in what scenario 1) would ever be repeated. In any case,
o's superclass's eigenclass is not part of o's inheritance chain:

class Animal
def self.greet
puts 'hi'
end
end

class Dog < Animal
end

o = Dog.new
puts o.class
puts o.class.superclass
o.greet

--output:--
Dog
Animal
1.rb:13:in `<main>': undefined method `greet' for
#<Dog:0x0000010086a050> (NoMethodError)

The error output is produced by method_missing.

--
Posted via http://www.ruby-forum.com/.

--
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 rubyonrails-talk@googlegroups.com.
To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.