Beyond the C++ Standard Library: An Introduction to Boost [Electronic resources] نسخه متنی

Operators Summary

Providing the correct set of relational and arithmetic operators for user-defined classes is vital and provides significant challenges to get right. With the use of the Operators library, this task is greatly simplified, and correctness and symmetry come almost for free. In addition to the help that the library offers in defining the full sets of operators, the naming and definitions of the concepts that a class can support is made explicit in the definition of the class (and by the Operators library!). In this chapter, we have seen several examples of how using this library improves programming with operators by simplification and ensured correctness. It is a sad fact that providing important relational and arithmetic operators for user-defined types is often overlooked, and part of the reason is that there is so much work involved to get it right. This is no longer the case, and Boost.Operators is the reason why.

An important consideration when providing relational and arithmetic operators is to make sure that they are warranted in the first place. When there is an ordering relation between types, or for numeric types, this is always the case, but for other types of classes, operators may not convey intent clearly. Operators are almost always syntactic sugar, and the importance of syntactic sugar must never be underestimated. Unfortunately, operators are also seductive. Use them wisely, for they wield vast power. When you choose to add operators to a class, the Boost.Operators library increases the quality and efficiency of your work. The conclusion is that you should augment your classes with operators only after careful thought, and use the Operators library whenever you get the chance!