Roots of Lisp

This is the implementation of original Lisp from 1960 as described in Paul Graham's article

How to use

Building

If you just want to run the project, you don't need to build it. The dist folder is already included there.

In order to build the project, you need Yarn V3.

in order to build the project, you can run yarn build or yarn build:dev for watch mode.

Running

This project uses EcmaScript Modules (ESM). They are supported by the latest LTS Node versions. In order to run the project, you can use the commands:

yarn start or npm start

or simply node dist/index.mjs

You will see the promt input>

Testing

This project uses the Node.js test runner from version 18. Build the project and run yarn test or simply node --test or even node eval.test.mjs. Once you see the result, you can hit Ctrl-C to finish testing.

What you can do with it

Original Lisp is a pretty poor language. It has only symbols, lists and functions.

You can try to check the equality of 2 symbols like this:

(eq 'a 'a)

The prompt should return you t which stands for true.

(eq 'a 'b) will return you (), empty list which stands for false.

You can find more information in the original article

Why it's cool

This repository also has a file eval.lisp, copied from Paul Graham's website.

If you run in the prompt (load-file 'eval.lisp), you will then be able to use the functions described in that file.

The most important function is eval., which is the Lisp interpreter written in itself.

You can then run, for example, (eval. '(eq 'a 'a) '()) and get the same result: t.

What it means: you run a Lisp interpreter that interprets the eval. function that can interpret any Lisp expression.