puzzle for student presentation
build a “shell” with history that works like this:
- (define m (mk-shell))
- (m ‘execute p) ; executes the procedure p and sets p to be the current proc
- (m ‘back) ; sets the current proc back one
- (m ‘forward) ; sets the current proc forward one
- (m ‘run) ; executes the current proc
hint
- use the circular buffer we designed last time!