This is a library for computing context menus based on text properties and overlays. The intended use is to have tools that annotate source code and others that use these annotations, without requiring a direct coupling between them, but maintaining discoverability. Major modes that wish to use this library should first define an appropriate value for `prop-menu-item-functions'. Then, they should bind `prop-menu-by-completing-read' to an appropriate key. Optionally, a mouse pop-up can be added by binding `prop-menu-show-menu' to a mouse event.