PC-LISP
| Developer | Peter Ashwood-Smith |
|---|---|
| Platform | i386, x86-64 |
| OS | Linux, macOS, Microsoft Windows, NetBSD |
| License |
|
| Influenced by | |
| Franz Lisp | |
PC-LISP is an implementation of the Franz Lisp dialect by Peter Ashwood-Smith.[1][2][3]
Version 2.07 was released on 1 February 1986,[4] and version 3.00 was released on 1 February 1990.[1] A current version is available through GitHub.[2]
Currently, PC-LISP has been ported to 32 & 64 bit versions of Linux, Mac, Windows[2] and NetBSD.[5] For NetBSD there also exists ports for AArch64, ARMv5/6/7, PowerPC, Motorola 68000, SPARC/SPARC64, Alpha and VAX.[5]
Note that the Franz LISP dialect was the immediate, portable successor to the ITS version of Maclisp[6] and is perhaps the closest thing to the LISP in the Steven Levy book Hackers as is practical to operate.[citation needed]
PC-LISP is written primarily in the C programming language, with some parts now also written in Common Lisp.[2] PC-LISP runs well in DOS emulators and on modern Windows versions. Because PC-LISP implements Franz LISP, it is a dynamically scoped predecessor to modern Common Lisp. This is therefore an historically important implementation.
Example
The session is running the following code which demonstrates dynamic scoping in Franz LISP. Note that PC-LISP does not implement the let special form that Emacs Lisp provides for local variables. Instead, all variables are what an ALGOL-based language would call "global". The first dialect of Lisp to incorporate ALGOL scoping rules (called lexical scoping) was Scheme although the Common Lisp language also added this feature.[citation needed]
;; Demonstration of dynamic scoping
;; This is a "global" variable
(setq myglobal "this is my global variable")
;; Another global variable
(setq yourglobal "this is my global variable")
;; a function which prints the symbols
(defun dosomething (mine yours)
(princ " * Mine is - ")
(princ mine)
(princ "\n")
(princ " * Yours is - ")
(princ yours)
(princ "\n"))
;; override the symbols
(defun nolocals ()
(setq mine "I have set mine to a new value")
(setq yours "I have set yours to a new value")
(dosomething mine yours))
(defun main ()
;; define two symbols
(setq mine myglobal)
(setq yours yourglobal)
;; print them
(princ "calling dosomething\n")
(dosomething mine yours)
(princ "calling nolocals\n")
(nolocals)
(princ "calling dosomething again\n")
(dosomething mine yours))
Another example showing the use of backquote and the power of LISP. This is a differentiation example.[citation needed]
; D(e,X) -
; Will compute the symbolic derivative of expression e with respect
; to variable X. We take the expression in standard lisp prefix form and will
; use the following rules of differentiation.
;
; D(x) = 1
; D(a) = 0
; D(ln u) = D(u)/u
; D(u+v) = D(u)+D(v)
; D(u-v) = D(u)-D(v)
; D(u*v) = D(u)*v + u*D(v)
; D(u/v) = D(u)*v + (u*D(v))/v^2
; D(v^u) = (v^u)*(u*D(v)/v + D(u)*ln(v))
;
(defun D(e X &aux u v)
(cond ((equal e X) 1)
((atom e) 0)
(t (setq u (cadr e) v (caddr e))
(caseq (car e)
(ln `(/ ,(D u X) ,u))
(+ `(+ ,(D u X) ,(D v X)))
(- `(- ,(D u X) ,(D v X)))
(* `(+ (* ,(D u X) ,v) (* ,(D v X) ,u)))
(/ `(- (/ ,(D u X) ,v)
(/ (* ,u ,(D v X)) (^ ,v 2))))
(^ `(* ,e (+ (/ (* ,v ,(D u X)) ,u)
(* ,(D v X) (ln ,u)))))
(t (princ "ERROR") (exit)]
References
- ^ a b Ashwood-Smith, Peter (1 February 1990). "PC-LISP V3.00 (C) February 1st 1990 Peter Ashwood-Smith". Carnegie Mellon University - School of Computer Science. Retrieved 14 November 2024.
- ^ a b c d "blakemcbride/PC-LISP". 4 August 2020. Retrieved 14 November 2024 – via GitHub.
- ^ Ashwood-Smith, Peter (May 1987). Van Deusen, Mary S. (ed.). "PC-LISP". LISP Pointers. Vol. 1, no. 1. pp. 51–52. Retrieved 14 November 2024.
- ^ Ashwood-Smith, Peter (20 February 1986). "A GUIDE TO THE PC-LISP INTERPRETER (V2.07)". The Unix Heritage Society. Retrieved 14 November 2024.
- ^ a b "lang/pc-lisp - The NetBSD Packages Collection". NetBSD. Retrieved 14 November 2024.
- ^ Foderaro, John K.; Sklower, Keith L.; Layer, Kevin (June 1983). "FRANZ LISP". The FRANZ LISP Manual (PDF). p. 5 – via GitHub.