Lambda Talk is a language that looks like Lisp, but is based on character string processing. The code is literally the text you see, with the parentheses (braces, actually) and all. Evaluation proceeds by term rewriting using textual substitution.

Similar work:

* James Gosling of Java made something called "Mock Lisp" in the 1980's to support an Emacs editor: Now deleted Wikipedia page: https://en.wikipedia.org/wiki/Mocklisp

* Lisp in Sed: https://github.com/shinh/sedlisp