"This is the fourth post in a series on Emacs completion. The first argued that Incremental Completing Read (ICR) is a structural property of an interface rather than a convenience feature. The second broke the Emacs substrate into eight packages (collectively VOMPECCC) each solving one of the six orthogonal concerns of a complete completion system. The third walked through spot, a ~1,100-line Spotify client built as a little shim on top of those packages.

This post is the hands-on complement to the spot post. Where the spot case study reviewed a finished codebase from the outside, this one builds a tiny produce picker tool from scratch, one VOMPECCC package at a time. The use case is deliberately trivial: we have a list of produce items (twenty fruits and ten vegetables) with some metadata, and we want to pick one and do something with it."