lake/Readme.md

Lake Scheme

A quick and dirty scheme written in C, for fun and to use while reading The Little Schemer. Very quick and dirty, a weekend hack gone awry.

Compiling & Running

Portable C99, only dep is glib, nothing to configure, no documentation!

Install glib 2.x using your package manager, for me it's either brew install glib or sudo aptitude install glib. Once you have glib just run:

$ make && ./lake

That will drop you at a repl. There are booleans, symbols, integers, strings, lists, dotted lists (pairs), lambdas, special forms, and a few primitive functions.

> #t
#t
> (quote symbol)
symbol
> 101
101
> "hello"
"hello"
> (quote (1 2 3 4))
(1 2 3 4)
> (quote (1 . 2))
(1 . 2)
> (lambda () "hello")
(lambda () "hello")
> (define inc (lambda (x) (+ x 1)))

Hooray! It parses (reads), evaluates, and then prints things back.

The special forms present so far are: quote, define, set!, and, or, and lambda.

> (define answer 7)
> answer
7
> (set! answer 42)
> answer
42
> (define list (lambda rest rest))
> (list 1 2 3 4)
(1 2 3 4)

Woah, we even managed to define a useful function without using any primitives! There are primitives now though. So few they can be easily named. They are named thusly:

• null?
• pair?
• not
• math operations: add, subtract, multiply, and divide (+ - * /)
• numeric equals (=)

Lake still needs:

• primitives:
  • display values
  • compare values
  • basic control flow (if, cond, when)
  • native type operations:
    • symbol
    • boolean (logic)
    • string
    • function
    • list (cons, car, cdr, ...)
    • dotted list (head, tail)
• a minimal stdlib

I don't think I'll need any other numeric types. Similarly I don't intend to add features expected from real languages, such as exception handling, I/O, GC, etc.

Contributors

None of them want any credit.

License

Copyright 2011 Sami Samhuri

MIT License, see included LICENSE file