Aca

Aca, a functional programming language, and shitty toy.

Aca is a toy functional programming language initially inspired by ISWIM. The interpreter is currently written in Python.

Install

$ pip install acalang

Example

1. Command line usage

$ cat foo.aca
let main =
    dechurch 3

$ aca foo.aca
3

$ aca foo.aca -S    # `noeval' mode
(lambda x: dechurch(x))((lambda x: x)((lambda f: lambda x: (f(f(f(x)))))))

$ aca       # REPL
$ aca -S    # REPL with `noeval'

2. Lambda calculus

let main =
    (\x y f. f x y)

3. Standard library for basic datatypes

let a = zero
let b = succ zero
let main = dechurch b
-- 1

4. Sugar for Church numerals

let main = 0

-- This is identical to
{-
let main =
    (\x . x)
-}

5. Special builtin functions for debugging (decoded into Python value)

let main =
    dechurch 42
-- Output: 42

let main =
    debool true
-- Output: True

let main =
    dereal (neg (u2i 42))
-- Output: -42

6. Simple module import with use

$ foo.aca
let foo = 42

$ bar.aca
use foo

let main =
    dechurch foo

$ aca bar.aca
42

Goals

• Before v1.0.0:
  • Untyped lambda calculus
• v1.0.0:
  • Simply typed lambda calculus
• v2.0.0:
  • System F

License

MIT