SLip — a Lisp system in JavaScript

This is a Lisp system in JavaScript, the goal being to be able to run Lisp in a browser.

Update: the project has been renamed SLip, but I didn't redo the screencast. If you want to follow the steps in the demo, you now need to type "SL" (that's the main package name) instead of "SS".

Features

• Self-hosting compiler
• Lexical and dynamic variables
• tagbody/go, throw/catch, block/return, unwind-protect
• Scheme-like first-class continuations (not to be used with unwind-protect though)
• Separate function/variable namespace (that might be a “misfeature”, depending how you look at it).
• Tail call optimization
• Common Lisp-like package system
• Tons of primitive functions
• loop, format and a pretty printer
• A simple “foreign function interface” for writing functions in JavaScript
• Most basic datatypes are unboxed—strings, numbers, arrays, regexps—so they can be freely passed around to JavaScript functions
• Literal regexps (seriously)
• Simple scheduler to emulate threads
• Contains a port of TinyCLOS object system (it's slow)
• Condition system based on TinyCLOS (handler-bind and handler-case)
• Very basic error detection (warns about undefined functions/variables; runtime type checking in primitives and VM instructions)
• An in-browser development environment inspired by Emacs and SLIME (based on Ymacs).

Live demo

Start hacking!