A language specific answer: The testing package of the Go standard library has a built-in support for examples. They are executed as part of the tests, but are

A language specific answer: The testing package of the Go standard library has a built-in support for examples. They are executed as part of the tests, but are rendered by the documentation generator as examples. This obviously only solves the problem of library writes that want to expose examples of library usage (and ensure they don't get stale)