Emacs Lisp

This is the archived website of SI 413 from the Fall 2012 semester. Feel free to browse around; you may also find more recent offerings at my teaching page.

You already know about Lisp; it's one of the oldest programming languages, and it's still used in lots of different places. It launched a revolution in functional programming, and has many descendant languages such as Scheme.

You probably also know about the text editor emacs. It's basically one of two options for real, hardcore text editing in *nix operating systems (the other option is VI).

But did you know that emacs is actually written in Lisp? Go to any emacs buffer and type a simple expression like (+ 10 12), then put your cursor after the closing paren and do Ctrl-x Ctrl-e. The answer shows up at the bottom of the screen!

You see, emacs is much more than a simple text editor. It is practically its own operating system, and the fact that it's all programmed (internally) in its own version of Lisp makes it very easy to write emacs extensions in Lisp too, or to accomplish simple programming tasks and run them from within emacs. That's what you'll be doing for this project.

Useful Links

How I will run your code

The programs you submit should be in a single file called proj.lisp. I will of course run your code from within emacs, by first typing

emacs proj.lisp
from the command line, and then running it by doing
Alt-x eval-buffer
from within emacs (in emacs-speak, the Alt-x is usually written M-x). I will do this all from within the CS linux environment, naturally.

Phase 1 Requirements

For this language, you need to implement modifications A, B, C, G, and H. See the Phase 1 page for details on what this means.

In emacs Lisp, your output should always be to a new emacs buffer that also gets displayed by your program. For part (H), you also need to open the "out.txt" file in emacs at the end, after you've written to it.

Phase 2

See the Phase 2 Page for the list of suggested problems. Of the ones listed, I recommend the following as being most well-suited for emacs lisp:

  1. Compiler
  2. Matrix Calculator
  3. Image Creator
  4. Hangman
  5. TODO list
  6. Guess the language
  7. Find the missing digits
  8. ??? (you choose!)