Scheme-workbench is a project mainly written in C, it's free.
a simple repl with edit mode.
scheme-workbench is a minimalistic repl intented to get rid of the emacs-dependencie that many newcomers face when entering lisp ground.
It offers 4 imperative features for lisp coding:
example:
in [1]:(define (fact x) ..: (if (= x 0) 1 ..: (* x (fact (- x 1)))))
in [2]:(fact 10) 3628800
in [3]:,ns fact
in [4]:(define x 1)
in [5]:,ns fact x
in [6]:,s fact my-math.scm