Among other things, I actually modified liner to stop using/swallowing all control codes, and to instead surface some of them to the client program to decide how to respond. e.g. liner stops doing anything with Ctrl-X (0x18 ?) and instead ng could respond to Ctrl-X by writing a docstring to stderr for an identifier under the caret in the input buffer.
I fear I may hit a wall with it eventually. For example, several interesting approaches to https://github.com/neugram/ng/issues/49 would step outside what liner can do. But I'm going to use it as long as I can.