package p5scm

  1. Overview
  2. Docs
Scheme via camlp5


Dune Dependency






This a simple scheme implementation using pa_schemer from camlp5

Published: 06 Apr 2023


A Scheme Implementation using Pa_schemer from Camlp5

This repository contains a scheme implementation based on 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.


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).



Dependencies (8)

  1. utop >= "2.7.0"
  2. ppx_sexp_conv >= "v0.14.0"
  3. sexp_pretty >= "v0.14.0"
  4. camlp5 >= "8.01.00"
  5. cppo >= "1.6.6"
  6. menhir >= "20201214"
  7. ocaml >= "4.12.0" & < "4.15.0"
  8. dune >= "2.8"

Dev Dependencies (1)

  1. odoc with-doc

Used by





Innovation. Community. Security.