> Consider something like filepath.Walk in go; you give it a function that gets called for every file and directory in the root of your choosing. They don't cal

> Consider something like filepath.Walk in go; you give it a function that gets called for every file and directory in the root of your choosing. They don't call it a visitor, though, they call it a "walk function". The ironic thing is that golang doesn't have an even better construct for this kind of pattern, namely pattern matching.