Method lookup chain in Ruby - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the method lookup chain in Ruby?

It is the order Ruby follows to find a method when you call it on an object. Ruby looks in the object's class, then included modules, then superclasses, and so on until it finds the method or raises an error.

beginner

In Ruby, where does the method lookup start when you call a method on an object?

It starts in the object's own class, checking if the method is defined there first.

intermediate

How do modules affect the method lookup chain in Ruby?

Modules included in a class are checked after the class itself but before the superclass. This allows modules to add or override methods in the lookup chain.

beginner

What happens if Ruby cannot find a method in the entire lookup chain?

Ruby raises a NoMethodError, meaning the method does not exist for that object.

intermediate

Explain the role of super in the method lookup chain.

The <code>super</code> keyword calls the same method from the next place in the lookup chain, usually the superclass or included module, allowing method extension or override.

Where does Ruby look first when you call a method on an object?

A The object's class

B The superclass

C Included modules

D Kernel module

Ruby starts looking for the method in the object's own class first.

If a method is not found in the object's class, where does Ruby look next?

A Superclass

B Included modules

C Object class

D Top-level methods

Ruby checks included modules next, before moving to the superclass.

What error does Ruby raise if a method is not found in the lookup chain?

A TypeError

B NameError

C ArgumentError

D NoMethodError

Ruby raises NoMethodError when it cannot find the method.

What does the super keyword do in a method?

A Stops method lookup

B Defines a new method

C Calls a method with the same name in the superclass or included module

D Calls a method in the current class

super calls the same method from the next place in the lookup chain.

Which of these is NOT part of Ruby's method lookup chain?

A Global variables

B Object's class

C Superclass

D Included modules

Global variables are not part of the method lookup chain.

Describe the order Ruby follows to find a method when you call it on an object.

Think about where Ruby looks first and what happens if it doesn't find the method.

Explain how the super keyword interacts with the method lookup chain.

Consider what happens when you want to reuse or add to a method from a parent class.