Self-documenting

In computer programming, self-documenting (or self-describing) is a common descriptor for source code that follows certain loosely-defined conventions for naming and structure. These conventions are intended to enable developers, users and maintainers of a system to use it effectively without requiring previous knowledge of its specification, design, or behavior.

Overview

The concept of self-description is not exclusively a property of certain kinds of source code. This concept has application to several areas in computer science, notably in computational linguistics and formal language theory. Additionally, self-describing systems may involve other areas in computing such as application design and user interfaces. Nevertheless, "self-documenting" is a term commonly used to designate a particular style of writing applied to source code for programming languages, markup languages and the like.

The designation of "self-documenting code" is often applied in a general sense, and not thoroughly defined according to a rigorous and exacting standard. Nevertheless, there are certain objectives, conventions, and practical considerations that usually apply when users of a system refer to this concept.

Objectives

Commonly stated objectives for self-documenting systems include:

• make source code easier to read and understand;
• minimize the effort required to maintain or extend legacy systems;
• reduce the need for users and developers of a system to consult secondary documentation sources; and
• facilitate automation through self-contained Knowledge representation.

Conventions

Self-documenting code is ostensibly written using human-readable names, typically consisting of a phrase in English which reflects the symbol's meaning, such as numberOfWordsInThisArticle or TryOpen. The code must also have a clear and clean structure so that a human reader can easily understand the algorithm used.

Practical considerations

There are certain practical considerations that influence whether and how well the objectives for a self-documenting system can be realized.

• uniformity of naming conventions
• consistency
• scope of the application and system requirements

Examples

An example of self-documenting software is TeX. When running on its own source code, TeX can produce a file with the complete printable documentation of itself.

Notes and references

See also

• Literate Programming
• Comment

External links

• Jef Raskin on Self-documenting code: http://acmqueue.com/modules.php?name=Content&pa=showpage&pid=290&page=1.
• Steve McConnell's High Quality Routines checklist in his book Code Complete helps to facilitate the creation of self-documenting code.