package p5scm

A Scheme Implementation using Pa_schemer from Camlp5

This repository contains a scheme implementation based on pa_schemer.ml which is included as an extension of camlp5. This provides a scheme-like syntax for OCaml. The camlp5 documentation for the scheme extension provides the following comparison between OCaml and scheme syntax:

| OCaml | Scheme | ------------------------------------ | ---------------------------------- | let x = 42;; | (define x 42) | let f x = 0;; | (define (f x) 0) | let rec f x y = 0;; | (definerec (f x y) 0) | let x = 42 and y = 27 in x + y;; | (let ((x 42) (y 27)) (+ x y)) | let x = 42 in let y = 27 in x + y;; | (let* ((x 42) (y 27)) (+ x y)) | module M = struct ... end;; | (module M (struct ...)) | type 'a t = A of 'a * int | B | (type (t 'a) (sum (A 'a int) (B))) | fun x y -> x | (lambda (x y) x) | x; y; z | (begin x y z) | f x y | (f x y) | [1; 2; 3] | [1 2 3] | a, b, c | (values a b c) | match x with 'A'..'Z' -> "x" | (match x ((range 'A' 'Z') "x"))) | {x = y; z = t} | {(x y) (z t)}

p5scm also provides the following:

| OCaml | Scheme | ------------------------------------ | ---------------------------------- | [|1; 2; 3|] | #(1 2 3)

which is provided via a simple menhir parser that supports all of the syntax above.

Installation

As long as you have a current version of opam, installation is as simple as:

$ opam install p5scm

You can then use it to parse and emit OCaml bytecode that can then be used in your OCaml project:

$ p5scm file1.scm

You can also start an interpreter for p5scm:

$ p5sch-utop

which uses utop for code completion and many of the other benefits that it provides. Currently both the #require and #use directives of utop function in the interpreter/REPL (same syntax as utop however no terminating ;; required).

Only OCaml versions >= 4.12.0 are supported by the opam package. Instructions for adding support for older versions can be found (here).

License

MIT