Advanced Perl Programming

Chapter 2. Implementing Complex Data Structures

Don’t worry, spiders,I keep house casually.

—Kobayashi Issa

The success of Perl is a tribute to the fact that many problems can be solved by using just its fundamental data types. Jon Bentley’s books Programming Pearls and More Programming Pearls are further testament to how much can be achieved if the basic data structures are dynamic and memory management is automatic. But as programs become more complex, moving from the domain of the script to that of the application, there is an increasing need for representing data in much more complex ways than can sometimes be achieved with the basic data types alone.

In this chapter, we will apply the syntax and concepts learned in Chapter 1 to a few “real” examples. We will write bits of code that build complex structures from file-based data and use sequences of $’s and @’s without batting an eyelid. For each problem, we will examine different ways of representing the same data and study the trade-offs in program versus programmer efficiency. In the interest of clarity, we will not worry too much about error handling.

Tom Christiansen has written an excellent series of tutorials called FMTEYEWTK (Far More Than Everything You’ve Ever Wanted to Know!) [Section 2.6]. This series contains a motley collection of topics that crop up on the Perl Usenet groups. I admire them for their lucid, patient, and detailed explanations and recommend that you read them at some point. (Now is better!) Some of ...