SAMS Teach Yourself Perl in 24 Hours THIRD EDITION

Hour 17. Writing Modules

What You'll Learn in This Hour:

• Building a module

• Scoping

• The our Statement

In Hour 8, “Functions,” you learned about subroutines. Subroutines allow you to take a frequently used pieces of code and assign it a name to create a small self-contained “mini-program” with its own variables.

After you've written enough programs, you'll find yourself creating the same functions over and over again for tasks. If you write a lot of file-manipulation programs, you'll probably have code to lock files and unlock them in several places; programs with user interaction (prompts and input) will have functions to display prompts, wait for answers, and reject bad input; and programs that work with a particular database might have functions ...