Smalltalk Best Practice Patterns

by Kent Beck

You can use Composed Method top-down. While you are writing a method, you can (without having an implementation yet) invoke several smaller methods. Composed Method becomes a thought tool for breaking your development into pieces. Here is an example of a top-down Composed Method: Controller>>controlActivity self controlInitialize. self controlLoop. self controlTerminate You can also use Composed Method bottom-up, to factor common code in a single place. If you find yourself using the same expression (which might be only 3 or 2 or even 1 line of code), you can improve your code by putting the expression in its own method and invoking it as needed.

top-down and bottom-up ways of ways of composing methods. Both ways have their advantages.