MLisp

A Lisp dialect implementation in OCaml5

Introduction

This project is the MLisp interpreter.

• This project is developed entirely in OCaml 5.0 (Current is OCaml5.0.0~alpha1)

Use

• REPL

> (env)
((pair . #<primitive:pair>) (+ . #<primitive:+>) (list . #<primitive:list>))
> (+ 3 5)
8
> (and #t #f)
#f
> (and #f #f)
#f
> (or #f #t)
#t
> (or #f #f)
#f
> (if (and #t #f) 3 4)
4
> (if (or #t #f) 3 4)
3
> (define x 3)
3
> (env)
((x . 3) (pair . #<primitive:pair>) (+ . #<primitive:+>) (list . #<primitive:list>))
> (+ x 7)
10
> (apply pair (list 3 4))
(3 . 4)
> (pair 5 6)
(5 . 6)
> (setq x (lambda (y) (+ y 1)))
#<closure>
> (x 10)
11
> (defun x (y) (+ y 1))
#<closure>
> (x 10)
11
> (defun f (x)
    (if (< x 2)
      1
      (g (- x 1))))
#<closure>
> (defun g (x)
    (if (< x 2)
      3
      (f (- x 2))))
#<closure>
> (f 10)
1
> (g 10)
3
> (let ((x 10)
        (y 20))
    (+ x y))
30
> (let* ((x 10)
         (y x))
    (+ x y))
20
> (letrec ((f (lambda (x) (g (+ x 1))))
           (g (lambda (x) (+ x 3))))                                                                       
    (f 0))
4
> Goodbye!

• Meta-circular

(eval. '((label fact
                (lambda (x)
                  (cond ((< x 2) 1)
                        (#t (* x (fact (- x 1)))))))
         5)
       '())

Since the loading mechanism is not currently implemented, it can be called in the following way:

./_build/default/bin/main.exe < bin/metacircular.mlisp

Or running with OCaml VM:

./_build/default/bin/main.bc < bin/metacircular.mlisp

Result:

> #<closure>
> #<closure>
> #<closure>
> #<primitive:pair>
> #<closure>
> #<closure>
> #<closure>
> #<closure>
> #<closure>
> #<closure>
> #<closure>
> #<closure>
> #<closure>
> #<closure>
> #<closure>
> #<closure>
> #<closure>
> 120
> Goodbye!

Build

• From source Since this project is developed using OCaml5, you need to install the OCaml5 environment. The current latest OCaml5 Release version is OCaml5.0.0~alpha1.You can install this version via opam update && opam switch create 5.0.0~alpha1 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git to install this version of OCaml environment.

• Dependencies

  1. This project is built with dune, you can install it with opam install dune

  2. The unit test set for this project is written using alcotest, which currently supports OCaml5.0.0~alpha1 and can be installed via opam install alcotest.

• Run Build

  1. Run dune build --profile release to build release version from source (or dune build --profile dev for dev)
  2. Run dune test to run all test cases
  3. Run dune exec ocamlisp to run the executable

License

Copyright (C) 2022 Muqiu Han

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License along with this program. If not, see https://www.gnu.org/licenses/.