While you follow Greenspun's tenth rule of programming (Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified, bug-ridden,

While you follow Greenspun's tenth rule of programming (Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp) you could embed a Lisp system, like ECL -> Embeddable Common Lisp https://common-lisp.net/project/ecl/ https://common-lisp.net/project/ecl/ There are a bunch of applications which include some kind of Lisp implementation in C. From GNU Emacs, Audacity, AutoCAD (and its various clones), and various others.