PAREN/C

PAREN/C is a customizable lispy language that compiles to C, with interoperability with Common Lisp.

(include :system ("stdio.h"))

(defun (main :int) ((argc :int) (argv :char**))
  (@printf (str "Hello, world!"))
  (return 0))
  
;; #include <stdio.h>
;;
;; int main(int argc,char **argv)
;; {
;;    printf("Hello, world!");
;;    return 0;
;; }

The ./examples directory contains several nontrivial examples. A standout is the full SectorLisp clone (./examples/sectorlisp.parenc and ./examples/sectorlisp.c), a turing-complete lisp programming language designed to fit within the master boot sector.

All examples in the ./examples directory are unit tested in ./test/paren.test.lisp. For instance, a test suite demonstrates how sectorlisp.parenc evaluates the metacircular evaluator. Additional examples will be added in the future.

Usage

The main function c compiles lisp forms into c code.

CL-USER> (asdf:test-system "paren" :force t) ; loads and tests the system
CL-USER> (in-package :paren)
PAREN> (c '(defun (main :int) ((argc :int) (argv :char**))
             (@printf (str "Hello, world!"))
             (return 0))) ;=>
"int main(int argc,char **argv)
{
    printf("Hello, world!");
    return 0;
}"

Interoperability through the LISP operator enables you to write paren/c code within lisp.

;; ./examples/nested-loops.parenc
(include :system ("stdio.h"))

(defun (main :int) ()
  ;; Stage 0 of compilation
  (LISP
   ;; A Common Lisp function that generates PARENC code as LISP lists.
     (defun multi-for (bindings body)
       (loop :for binding :in (reverse bindings)
             :do (setf body `((for ((declare () (,(nth 0 binding) :int) 0)
                                    (< ,(nth 0 binding) ,(nth 1 binding))
                                    (++ ,(nth 0 binding)))
                               ,@body))))
       (car body))
     (multi-for '((i 3) (j 2) (k 2))
                '((@printf (str "%d ") (+ i j k))
                  (@printf (str "%d\\n") i))))
  (return 0))

;;; Stage 1 of compilation (PARENC->PARENC)
;; (FOR ((DECLARE () (I :INT) 0) (< I 3) (++ I))
;;  (FOR ((DECLARE () (J :INT) 0) (< J 2) (++ J))
;;   (FOR ((DECLARE () (K :INT) 0) (< K 2) (++ K))
;;        (@PRINTF (STR "%d ") (+ I J K))
;;        (@PRINTF (STR "%d\\n") I))))

;;; Stage 2 of compilation (PARENC -> C)
;; for (int i = 0; ((i) < (3)); ((i)++)) {
;;   for (int j = 0; ((j) < (2)); ((j)++)) {
;;     for (int k = 0; ((k) < (2)); ((k)++)) {
;;       printf("%d ", ((i) + (j) + (k)));
;;       printf("%d\n", i);
;;     }
;;   }
;; }

State of the Project

We are currently refining the language by porting additional C code into PAREN/C. It is not ready for use yet. Contributions are welcome (see TODO.md for details).