Exceptions

There are highly specialized libraries (e.g., parser generators and regular expression engines) that define domain-specific conventions for operators that are very different from their C++ meanings (e.g., a regular expression engine might use operator* to express “zero or more”). Prefer instead to find an alternative to unusual operator overloading (e.g., [C++TR104] regular expressions use strings, so that * can be used naturally without overloading operators). If after careful thought you choose to use operators anyway, make sure you define a coherent framework for your conventions and that you don’t step on the toes of any built-in operator.