Erlang Programming

Chapter 20. Style and Efficiency

Throughout this book, we have covered the do and don’ts of Erlang programming. We have introduced good practices and efficient constructs while pointing out bad practices, inefficiencies, and bottlenecks. Some of these guidelines you will probably recognize as being relevant to computing in general; others will be Erlang-related, and some will be virtual-machine-dependent. Learning to write efficient and elegant Erlang code will not happen overnight. In this chapter, we summarize design guidelines and programming strategies to use when developing Erlang systems. We cover common mistakes and inefficiencies and look at memory handling and profiling.

Applications and Modules

A collection of tightly interacting modules in Erlang is called an application. Erlang systems consist of a set of loosely coupled applications. It is good practice to design an application to provide a single point of entry for calls originating from other applications. Collecting all externally exported functions into one module provides flexibility in maintaining the code base, since modifications to all “internal” modules are not visible to external users. The documentation for this module gives a complete description of the interface to the application. This single point of entry also facilitates tracing and debugging of the call flow into the application. In large systems, it is good practice to prefix the modules in a particular application with a short acronym. This ensures ...