LISc

List Interpretation in Scala

Overview

This is a toy LISP interpreter written in pure Scala. It is still early days and plenty of language features are missing, but the code is at least runnable, with a very basic REPL.

Usage

Fire up SBT, hit run, and you'll get a basic REPL:

$ sbt run

...

Welcome to LISc!
This is a toy Lisp interpreter, written in Scala.
Type :q to leave
    
lisc> (defn fact [x] (if (<= x 1) 1 (* x (fact (- x 1)))))
==> ()
lisc> (fact 5)
==> 120

Type :q to exit the REPL.

Special Forms

Currently four, with naming inspiration nabbed from Clojure:

• (if test then else) - as you might expect
• (def name value) - binds a value to the result of the expression
• (fn [args] body) - defines a lambda function
• (defn name [args] body) - helper for binding a function (to be replaced by a macro once they're implemented)