This makes me think of Expressions of Change [1], a project that aimed to make updates to a program a first-class primitive in a programming language. A model l

This makes me think of Expressions of Change [1], a project that aimed to make updates to a program a first-class primitive in a programming language. A model like this can't output code directly, but perhaps it would be well suited to select from the small set of discrete operations on code envisioned by the EoC author? [1]: www.expressionsofchange.org