Mini Lisp Interpreter

Intro

This repo contains a mini version of a SCHEME interpreter. SCHEME is an implementation of LISP that focuses on minimalism and avoids a lot of the cruft that is present in Common LISP. However, while being similar to MIT SCHEME, this interpreter only implements a fraction of the specification. You can see the supported operations under the goal section of the document.

Goals

Our primary goal is to implement a minimal Lisp Read-Eval-Print-Loop. Because we are focusing on a minimal implementation there are only a few keywords used in this implementation.

• lambda
• quote
• =
• car
• cdr
• if
• and
• or
• not

Along with these keywords I am adding a few elementary operators for use with mathematical programs.

• +
• -
• *
• /
• %
• >
• <

Results

Comparison Operators

> (define n 1)
n
> (define m 2)
m
> (= m n)
#f
> (define T #t)
T
> (define T2 #t)
T2
> (= T T2)
#t
> (define l1 (quote (1 2 3 4 5)))
l1
> (define l2 (quote (2 3 4 5 1)))
l2
> (= l2 l1)
#f
> (define l3 (quote (1 2 3 4 5)))
l3
> (= l3 l1)
#t

Mathematical Operations

> (define x 2)
x
> (define y 3)
y
> (+ x y)
5
> (* x y)
6
> (/ x y)
0.6666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666667
> (- x y)
-1
> (- y x)
1
> (* x y y)
18
> (% 16 512)
16
> (% 512 16)
0
> (% 4 3)
1

List Operations

> (quote (1 2 3 4))
(1 2 3 4)
> (define ages (quote (35 67 23 44)))
ages
> (car ages)
35
> (cdr ages)
(67 23 44)
> (car (cdr (ages)))
67