README.md

CSE 6341 Lisp Interpreter

Welcome to the Lisp Interpreter README. In this document, we'll cover exactly how to build and execute the Lisp REPL.

Build and Run

In order to build and run the Lisp REPL, you can attempt the following:

$ ./run.sh

This file contains all the necessary code to build the java files, run the interpreter, and clean up the java files following execution. Feel free to take a look at the file to see how it works.

REPL

Once executed, the REPL should launch with a message that reads:

Welcome to the CSE6341 Lisp Interpreter by Jeremy Grifski!
You've just launched the Lisp REPL.
To evaluate an s-expression, place a $ on a single line.
To exit the REPL, place $$ on a single line.

Following this message, you should see a lisp-interpreter>. This indicates where you can begin typing. Feel free to input your text here.

When you're finished writing your s-expression, enter a dollar sign ($) on a single line. This will cause the REPL to parse and evaluate the s-expression you've entered. If successful, you'll see something like the following:

Dot Notation: (EQ . (1 . (2 . NIL)))
Result: NIL

Alternatively, you could see some errors in the following form:

Dot Notation: (EQ . (1 . (2 . (3 . NIL))))
osu.cse6341.LispEvaluationException: Invalid list of arguments for EQ: (1 . (2 . (3 . NIL)))

When you're done, enter a pair of dollar signs ($$) on a single line. This terminates the program. If successful, you should see Goodbye!.

File Redirection

Alternatively, you can safely automate the interpreter by piping several s-expressions from a file such as the following:

(2 3)
$
(x 4 5 (3 4))
$
$$

Assuming this file is named lisp.txt, you can redirect it to the jar file as follows:

$ ./run.sh < lisp.txt

Be careful not to include your test file in the directory because will be deleted after testing. The run.sh file leverages git to clean the repo of all files not currently tracked. As a result, new files will be deleted.

If you run into an problems, let me know!

Notes on Syntax

This solution was originally written using the following DEFUN syntax:

(DEFUN SILLY (A B) (PLUS A B))

However, the directions were later updated to support the new DEFUN syntax:

(DEFUN (SILLY (A B)) (PLUS A B))

I have since updated my solution to cover this new DEFUN syntax. All tests pass for the new syntax. The old syntax is no longer supported.