nunb / lisp-in-dart

A fast Lisp interpreter in Dart

Lisp in Dart

This is a small Lisp interpreter I wrote 3 years ago (2015) in Dart. It had been presented under the MIT License at http://www.oki-osk.jp/esc/dart/lisp.html until last spring (2017). Now I have slightly modified it to match Dart 2.0.

See IMPLEMENTATION-NOTES.md for the details of implementation.

How to use

It runs in Dart 1.24 and later.

$ dart lisp.dart
> "hello, world"
"hello, world"
> (+ 5 6)
11
> (exit 0)
$

You can give it a file name of your Lisp script.

$ dart lisp.dart examples/fib15.l
987
$

If you put a "-" after the file name, it will begin an interactive session after running the file.

$ dart lisp.dart examples/fib15.l -
987
> (fib 0)
1
> (fib 1)
1
> (fib 2)
2
> (exit 0)
$ 

Examples

There are four files ending with .l under the examples folder. These run also in Emacs Lisp and Common Lisp. You will find the Lisp in Dart comparably fast to Emacs Lisp which is written in C.

$ dart lisp.dart examples/qsort.l
(1 1 2 3 3 4 5 5 5 6 7 8 9 9 9)
$ 

$ emacs -batch -l examples/qsort.l

(1 1 2 3 3 4 5 5 5 6 7 8 9 9 9)
$ 

$ clisp examples/qsort.l

(1 1 2 3 3 4 5 5 5 6 7 8 9 9 9)
$ 

• qsort.l performs a quick sort.

• fib15.l calculates Fibonacci for 15.

• eval-fib15.l calculates Fibonacci for 15 on a meta-circular Lisp evaluator.

• eval-eval-fib15.l calculates Fibonacci for 15 on a meta-circular Lisp evaluator on a meta-circular Lisp evaluator.

There is one more example:

• interp_in_isolate.dart runs a Lisp interpreter in another isolate of Dart. You can embed an interpreter within your Flutter app in the same way.

$ dart examples/interp_in_isolate.dart
=> 11
=> 1
=> (1)

The examples of eval-fib15.l and eval-eval-fib15.l are inspired by https://github.com/zick/ZickStandardLisp.

License

This is under the MIT License. See lisp.dart.