How to Balance Brevity and Abstraction

Abstraction is key to programming. You should carefully choose how abstract you need to be. Beginning programmers in their enthusiasm often create more abstraction than is really useful. One sign of this is if you create classes that don’t really contain any code and don’t really do anything except serve to abstract something. The attraction of this is understandable but the value of code brevity must be measured against the value of abstraction. Occasionally, one sees a mistake made by enthusiastic idealists: at the start of the project a lot of classes are defined that seem wonderfully abstract and one may speculate that they will handle every eventuality that may arise. As the project progresses and fatigue sets in, the code itself becomes messy. Function bodies become longer than they should be. The empty classes are a burden to document that is ignored when under pressure. The final result would have been better if the energy spent on abstraction had been spent on keeping things short and simple. This is a form of speculative programming. I strongly recommend the article ‘Succinctness is Power’ by Paul Graham.

There is a certain dogma associated with useful techniques such as information hiding and object oriented programming that are sometimes taken too far. These techniques let one code abstractly and anticipate change. I personally think, however, that you should not produce much speculative code. For example, it is an accepted style to hide an integer variable on an object behind mutators and accessors, so that the variable itself is not exposed, only the little interface to it. This does allow the implementation of that variable to be changed without affecting the calling code, and is perhaps appropriate to a library writer who must publish a very stable API. But I don’t think the benefit of this outweighs the cost of the wordiness of it when my team owns the calling code and hence can recode the caller as easily as the called. Four or five extra lines of code is a heavy price to pay for this speculative benefit.

Portability poses a similar problem. Should code be portable to a different computer, compiler, software system or platform, or simply easily ported? I think a non-portable, short-and-easily-ported piece of code is better than a long portable one. It is relatively easy and certainly a good idea to confine non-portable code to designated areas, such as a class that makes database queries that are specific to a given DBMS.

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