[buescher]

A long long time ago on a toy lisp called Interlisp/65 I used something that was like the s-exp equivalent of a line editor.

https://atariwiki.org/wiki/Wiki.jsp?page=Lisp

Source is here: https://atariwiki.org/wiki/Wiki.jsp?page=LispEditor

If you really wanted a vi-like experience for editing lisp, you could figure out how to make an editor like that full-screen and interactive.