https://github.com/jin/scheme.ml

Scheme (R6RS subset) interpreter written in OCaml
https://github.com/jin/scheme.ml

interpreter ocaml r6rs scheme

Last synced: 3 months ago
JSON representation

Scheme (R6RS subset) interpreter written in OCaml

• Host: GitHub
• URL: https://github.com/jin/scheme.ml
• Owner: jin
• Created: 2016-03-30T06:52:31.000Z (almost 9 years ago)
• Default Branch: master
• Last Pushed: 2020-06-30T09:33:30.000Z (over 4 years ago)
• Last Synced: 2023-03-11T13:49:39.377Z (almost 2 years ago)
• Topics: interpreter, ocaml, r6rs, scheme
• Language: OCaml
• Homepage:
• Size: 80.1 KB
• Stars: 16
• Watchers: 3
• Forks: 2
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

README

        
# Scheme interpreter in OCaml

See `test.ml` for the set of implemented Scheme syntax.

### How it works

```scheme

scheme> (&& #f #t)

DEBUG: Tokens: [LParen, &&, #f, #t, RParen]

DEBUG: S-Expression: List(Atom(&&) Atom(#f) Atom(#t))

DEBUG: Result: #f

#f

scheme> (if (< 1 2) 4 5)

DEBUG: Tokens: [LParen, Keyword(if), LParen, <, Number(1), Number(2), RParen, Number(4), Number(5), RParen]

DEBUG: S-Expression: List(Atom(if) List(Atom(<) Atom(1) Atom(2)) Atom(4) Atom(5))

DEBUG: Result: 4

4

scheme> (car '(a b c))

DEBUG: Tokens: [LParen, Keyword(car), Quote, LParen, Variable(a), Variable(b), Variable(c), RParen, RParen]

DEBUG: S-Expression: List(Atom(car) List(Atom(') Atom(a) Atom(b) Atom(c)))

DEBUG: Result: a

a

scheme> (cdr (cons 1 '((* 1 2) (if (< 1 2) 3 4))))

DEBUG: Tokens: [LParen, Keyword(cdr), LParen, Keyword(cons), Number(1), Quote, LParen, LParen, Multiply, Number(1), Number(2), RParen, LParen, Keyword(if), LParen, <, Number(1), Number(2), RParen, Number(3), Number(4), RParen, RParen, RParen, RParen]

DEBUG: S-Expression: List(Atom(cdr) List(Atom(cons) Atom(1) List(Atom(') List(Atom(Multiply) Atom(1) Atom(2)) List(Atom(if) List(Atom(<) Atom(1) Atom(2)) Atom(3) Atom(4)))))

DEBUG: Result: (2, 3)

(2, 3)

```

### Building and running

```sh

# install dependencies

opam install sedlex alcotest

# Build with either Make or [Bazel](https://bazel.io)

# MAKE

make

# run all examples and diffs output against respective expected output in examples/test

make test

# ----

# Bazel

bazel build //:scheme-bytecode # compiles the binary into bazel-bin/scheme-bytecode

# ----

# start the interpreter

./scheme

# or load a source file

./scheme examples/arithmetic.scm

```

### What's next 

In the order of features I want to look into.

- [ ] More separation of eval logic from lexer/parser

- [x] Binary should accept filenames and not read from STDIN

- [ ] `cond`

- [ ] Lambdas