[Libguestfs] [PATCH 0/4]: mllib: Add 'may' function, and refactoring.

The 'may' function is a higher-order function (HOF) that replaces: match x with | None -> () | Some x -> f x with: may f x The idea comes from lablgtk (OCaml Gtk bindings) where it is widely used. If this change is clearer than previous code, then this could be used in many more places. However I previously steered clear from using HOFs like this because they can be quite confusing for newcomers to functional programming. Rich.