Professional Xcode® 3

Chapter 10. Refactoring

WHAT'S IN THIS CHAPTER?

• Renaming classes, types, methods, functions, and variables

• Reorganizing code and restructuring classes

• Modernizing your code

Despite our best efforts, class and data structures don't always endure. New features, requirements, operating system evolution, and improvements elsewhere in your application may cause you to revisit the design of your existing class and data architecture. You may need to reorganize the hierarchy of your classes, migrate functionality from one class to another, take advantage of new language features, or simply rename a variable so that it more accurately reflects its purpose. These kinds of changes are referred to as refactoring your code.

Making structural changes to your code using the editor and the search and replace tools can often be tedious, time consuming, and error prone. In the days before refactoring, I would often rename or relocate an instance variable by simply changing its declaration, and then hunting down and correcting all of the compilation errors that resulted — not the most productive way to spend an afternoon.

Fortunately, Xcode now provides a refactoring tool that helps you make many common structural changes to your application, quickly and succinctly. It uses the Code Sense database and an inherent knowledge of C and Objective-C syntax to intelligently rename symbols, reorganize classes, and streamline code. This chapter describes the kinds of changes the refactoring tool performs and the ...