CSC/ECE 517 Fall 2007/wiki1b 1 c4

Introduction

Problem

If multiple methods with the same name are defined, there needs to be some way of determining which method a call refers to. The general rule is given on p. 123 of Programming Ruby. But questions still remain.

Questions

• Is it possible to get unexpected behavior if one of the modules you are using is "enhanced" to contain a new method that happens to conflict with a name of an existing method?
• Is it possible to refer to these methods using a qualified name?
• Is it possible to use method aliasing to resolve the ambiguity?
• What approach does good o-o design dictate?

Method

What is it?

A section of code that does or performs a task and then returns a value. A synonym for a method is a function. Methods can also be included within classes and used as accessors, mutators and setters.[2] Methods are created with the keyword def and the name of the method and end with the keyword end. A method is called by simply typing the name of the method and enclosing any parameters to the method in "()". i.e. some_method(some_parameter).[1]

General Rule For Multiple Methods

If multiple methods with are defined with the same name and a call is made to that method, Ruby will look in the immediate class of an object first for the method definition. It then will look in any mixins included within the class and lastly in any superclasses and their mixins. If multiple mixins are present the rule for searching is that the last one included will be search first.[1]

References

1. Programming Ruby: The Pragmatic Programmers' Guide
2. http://en.wikibooks.org/wiki/Programming:Ruby_Method_Calls