Some language features are just plain ugly. The first time you see them, you say to yourself, “If I ever have to use that, there’s something wrong with my design.” And most of the time you’d be right.

.NET and Java developers are perplexed about the indiscreet way C++ discloses private class details. Pimpl (pointer-to-implementation) solves this problem by keeping secrets hidden from peepers. I ...