OpenLisp

OpenLisp is a programming language in the Lisp family developed by Christian Jullien^[1] from Eligis. It conforms^[2][3][4] to the international standard for ISLISP published jointly by the International Organization for Standardization (ISO) and International Electrotechnical Commission (IEC), ISO/IEC 13816:1997(E),^[5][6] revised to ISO/IEC 13816:2007(E).^[7]

Written in the programming languages C and Lisp, it runs on most common operating systems. OpenLisp is designated an ISLISP implementation, but also contains many Common Lisp-compatible extensions (hashtable, readtable, package, defstruct, sequences, rational numbers) and other libraries (network socket, regular expression, XML, Portable Operating System Interface (POSIX), SQL, Lightweight Directory Access Protocol (LDAP)).^[8]

OpenLisp includes an interpreter associated to a read–eval–print loop (REPL), a Lisp Assembly Program (LAP) and a backend compiler for the language C.

Goals

The main goal of this

Despite its name, OpenLisp is proprietary software. Its interpreter is available free of charge for any noncommercial use.

User interface

OpenLisp mainly runs in console mode: cmd.exe on Microsoft Windows, and terminal emulator on Unix-based systems.

 ;; OpenLisp v11.x.y (Build: XXXX) by C. Jullien [Jan 01 20xx - 10:49:13]
 ;; Copyright (c) Eligis - 1988-20xx.
 ;; System 'sysname' (64-bit, 8 CPU) on 'hostname', ASCII.
 ;; God thank you, OpenLisp is back again!
 ? (fib 20)
 ;; elapsed time = 0.003s, (0 gc).
 = 6765
 ? _

Alternate solutions include running OpenLisp from Emacs via setting up Emacs inferior-lisp-mode, or using an integrated development environment (IDE) which supports OpenLisp syntax. LispIDE by DaanSystems does so natively.

Technology

Memory manager

Internally, OpenLisp uses virtual memory to allocate and extend objects automatically. Small objects of the same type are allocated using a Bibop (BIg Bag Of Pages) memory organization. Large objects use a proxy which point to the real object in Lisp heap. The conservative garbage collection is a mark and sweep with coalescing heap (sweep phase can be configured to use threads).

Data types

OpenLisp uses

In 1988, the very first motive behind OpenLisp was to implement a Lisp subset to extend EmACT, an Emacs clone. ISLISP became an obvious choice quickly. Further development ensued.

Ports

OpenLisp claims to be extremely portable, it runs on many

Some well known algorithms are available in ./contrib directory (Dantzig's simplex algorithm, Dijkstra's algorithm, Ford–Fulkerson algorithm). Modules are shipped using BSD licenses.

Origin of name

The prefix Open refers to

OpenLisp programming language is different than OpenLISP, a project begun in 1997 to implement Locator/Identifier Separation Protocol.

Compiler

This section describes how a compiler transforms Lisp code to C.

Source code

The

(defun fib (n)
   (cond ((eq n 1) 1)
         ((eq n 2) 1)
         (t (+ (fib (- n 1)) (fib (- n 2))))))

LAP intermediate code

Lisp compiler translates Lisp source code to the following intermediate code. It is followed by a peephole optimization pass that uses this intermediate format to analyze and optimize instructions. After optimization, final LAP code is:

  ((fentry fib 1 0 0)
   (param 0)
   (jeq _l004 '1)
   (jneq _l003 '2)
   (move a1 '1)
   (return)
  _l003
   (gsub1 a1)
   (recurse 1)
   (move a2 a1)
   (param 0)
   (gsub a1 '2)
   (recurse 1)
   (gadd a2 a1)
  _l004
   (return)
   (end))

C code translation

Finally, C code generator uses LAP code to translate instructions in C.

static POINTER 
OLDEFCOMPILED1(olfib_00, p1) {
        POINTER a1;
        POINTER VOLATILE a2;

        ollapenter(SN_OLFIB_00);
        a1 = p1;
        if (eq(a1, olmakefix(1))) goto _l004;
        if (!eq(a1, olmakefix(2))) goto _l003;
        ollapleave(SN_OLFIB_00);
        return olmakefix(1);
_l003:
        a1 = ollapgsub(a1, olmakefix(1));
        a2 = olfib_00(a1);
        a1 = ollapgsub(p1, olmakefix(2));
        a1 = olfib_00(a1);
        a1 = ollapgadd(a2, a1);
_l004:
        ollapleave(SN_OLFIB_00);
        return a1;
}

Style guide

Line length

OpenLisp accepts lines having unlimited length. The recommended style is that each line of text in code should have at most 80 characters per line.

Adoption

It has been chosen by SDF Public Access Unix System nonprofit public access Unix systems on the Internet^[12][13] as one of its programming languages available online.

Bricsys uses OpenLisp to implement

MEVA [15] is entirely written with OpenLisp.

Università degli Studi di Palermo uses OpenLisp to teach Lisp.^[16]

References