1. sudo apt-get mit-scheme;

2. run "scheme" then you enter the command line scheme repl;

3. sudo apt-get emacs;

4. modify "(setq scheme-program-name "scm")" in .emacs to "(setq scheme-program-name "scheme")", because our scheme command is "scheme";

5. install quack with apt-get install emacs-goodies-el;

6. open emacs and create a new buffer with "C-x C-f myfile.scm";

7. input following code:

(define (mydouble x)
(+ (* x 2) 10))

1. save file: C-x C-s;

2. split window: C-x 2;

3. switch to bottom window: C-x o;

4. start scheme repl at bottom window: M-x run-scheme

5. switch back to top window: C-x o;

6. parse code: C-x C-e;

7. switch back to bottom window(C-x o) and run "(mydouble 3)", you got 16;

8. modify source file in upper window and parse it again (C-x C-e);

9. run "(mydouble 3)" again, now you get another value;

Ref: A tutorial for using Emacs with Scheme