cl-lox

cl-lox is a fast fully-compliant Lox language implementation in Common Lisp with extra goodies.

If you're curious check the Crafting Interpreters book and learn how to write a complete language from scratch.

Installation

Run cl-lox inside a docker container or install it on your machine.

Docker Environment

Spin up a docker container with cl-lox:

bash run.sh

The first run takes longer, but then it's very fast.

Local Installation

With Roswell you don't even need to clone the repo, just run:

ros install albertoeaf/cl-lox

You can also install manually using Quicklisp or ASDF.

Usage

# Calling lox scripts (this demo prints the first 20 fibonacci numbers):
cl-lox --script demos/demo6-fun-fib.lox

# Running the interpreter (every empty line triggers the commands before to run):
cl-lox

Demos

You can try out all the demos without installing by using docker:

bash run.sh # spin up a docker instance with cl-lox
ros run # start a Lisp environment

Now run the following commands inside the Lisp environment:

;; Load cl-lox:
(asdf:make :cl-lox)
;; Run all the demos and time it:
(time (lox:run-demos "demos/"))

You should see the outputs of the several demos and the total time:

...

Creating bacon!
Crunch crunch crunch!
Only 1 slice(s) left of me!
Crunch crunch crunch!
Only 0 slice(s) left of me!
Only 0 slice(s) left of me!
Adding 3 slices of bacon!
Only 3 slice(s) left of me!
NIL


------------------------ Demo demo9-class-inheritance -------------------------
Running file /home/alberto.ferreira/code/external/AlbertoEAF/cl-lox/demos/demo9-class-inheritance.lox.

Fry until golden brown.
Pipe full of custard and coat with chocolate.
NIL
Evaluation took:
  0.164 seconds of real time
  0.164993 seconds of total run time (0.161349 user, 0.003644 system)
  [ Run times consist of 0.005 seconds GC time, and 0.160 seconds non-GC time. ]
  100.61% CPU
  477,229,056 processor cycles
  68,793,072 bytes consed

Language extensions

Safety:

• Evaluating uninitialized variables is forbidden.

Standard Library:

• clock() -> Timestamp in seconds
• readline() -> reads a string from the user
• readfile(path) -> whole file as a string

Extensions:

• + can sum numbers or concatenate strings with numbers.

Future work

For now I'm happy with it, but I might decide later to:

• Add enhancements to the language.
• Extend standard library.
• Further benchmark and improve performance.