Petite Chez Scheme Version 8.4 Copyright (c) 1985-2011 Cadence Research Systems > (load "chez-init.ss") > (load "C:\\SVN\\304\\Grading program\\AA Student submissions\\202110\\hoeventl-johnsoa8.ss") > (define read-and-parse (lambda () (let loop () (display "enter an expression: ") (let ([datum (read)]) (unless (eq? datum 'exit) (pretty-print (parse-exp datum)) (loop)))))) > (read-and-parse) enter an expression: 4 (lit-exp 4) enter an expression: a (var-exp a) enter an expression: 'a (lit-exp a) enter an expression: (a b c) (app-exp (var-exp a) ((var-exp b) (var-exp c))) enter an expression: '(a b c) (lit-exp (a b c)) enter an expression: ''(a b c) (lit-exp '(a b c)) enter an expression: exit > (parse-exp 'a) (var-exp a) > (parse-exp ''a) (lit-exp a) > (parse-exp ''(a b c)) (lit-exp (a b c)) > (parse-exp '''(a b c)) (lit-exp '(a b c)) > (quote (quote (a b c))) '(a b c) >