TweetFollow Us on Twitter

List Programming
Volume Number:1
Issue Number:6
Column Tag:LISP LISTENER

MACINTOSH List Programming

By Andy Cohen

Welcome to The Lisp Listener Window! This is the first of what we hope will become a regular column on programming Lisp on the Apple Macintosh. Lisp stands for List Programming and it is used for a very special type of computer programming in a field typically refered to as Artificial Intelligence or AI. Over the past five years AI has become a very popular and controversial topic. It has roots in Computer Science and Cognitive Psychology. The Psychologists found ways of describing human mental processes and the computer scientists have programmed these processes into computers, thereby getting the computer to perform human-like processing tasks.

Computers however, are definitely not one to one analogies to people. Computers process data. Human processes, on the other hand, deal with concepts. Lisp was designed specifically to handle the coding of these concepts by providing an object oriented, programm- ing environment. This development has provided us with programs that generate information by mimicking the same form of inductive reasoning as a person. In the case of specialized knowledge domains, these programs have been called Expert Systems. I will eventually try to emphasize on Lisp examples which will.

Take advantage of what makes Lisp different from the other languages covered in this publication. That is, it’s ability to manipulate objects, rather than just data, in a fashion similar to the way people do.

Is Lisp on the Mac Serious?

A friend asked me a little while ago if we will be able to program serious AI applications using Lisp? My first reaction was that we can’t. The smallest development system for an AI application has quite a bit more random access memory (from two to five Mbytes) and usually has a hard disk with more then 30 megabytes of space on which to read or write. The best we can hope for in the Macintosh environment (at the time this article was written!) is one megabyte of RAM and ten megabytes on a hard disk using the Mac XL. However, I also noted that sometimes the application is only developed using Lisp and then when finalized, the code is translated into a lower level language, such as Fortran. This recoding is done for speed and compactness.

My secondary feelings were yes, we probably can develop an AI application on the Mac to some extent, but the program will have to be translated into Pascal, C or even 68K Assembly. As it turns out, the version of Lisp coming from Expertelligence will allow us to do quite a bit with just 512K and two floppies. I’ll describe this package in detail later. Will we be able to use the Mac as an AI development machine? I am still sceptical, however I have a feeling that time will show us that it just might be possible. If you are asking, why would somebody program Lisp on the Mac at this time? I can only say one should use Lisp on the Mac for educational purposes. Heck, educational purposes are more than enough considering that a complete Lisp development system can cost over $75,000.00! Also consider that just a couple of years ago having Lisp on a micro-computer was almost as fictional as verbally asking your Mac to open the pod bay doors.

Different Lisps

Lisp comes in many different versions just like any other computer language. There is Zetalisp, Interlisp, Maclisp (not Macintosh) and some I’m sure I’ve never heard of. The versions of Lisp that are or will be available on the Macintosh are very close to Common Lisp. An excellent text for Common Lisp is “Lisp” 2nd ed. by Winston and Horn. All that I discuss in this article regarding Common Lisp follows what is in that text.

At the time this article was written only one version of Lisp was available. It is called XLisp and was developed by David Betz. It was programmed in C and was considered by Betz as an experimental language. There are two versions of XLisp that I have seen on the Mac; version 1.2 and version 1.4. Both versions of XLisp are interpreted. Only version 1.4 however, can handle object oriented programming. Unfortunately, XLisp 1.4 takes up most of the available memory on a 128K Mac. Either version of XLisp however, will work fine on a 128K Mac for demonstrating some of the arithmetic functions in Common Lisp syntax. The biggest advantage of XLisp is that it is Public Domain software. In other words, it is free. Look for it on Compuserve’s MAUG or to your local users’ group. Chances are it is available in one or more versions.

Lisp and Arithmetic

Enough small talk ( oops, sorry about that!) , now lets take a first look at Lisp. The most fundamental object in Lisp is an Atom. The atom is used in groups to produce Lists. Atoms and lists make up what are called expressions.

Okay, lets get a little more detail. A procedure specifies how something is performed. For example “+” or plus sign is a procedure. The “+” by itself is called a primitive. Numbers or symbols are refered to as arguments. Therefore the numbers 2.56 and 8.34 are arguments. These elements or atoms can be placed into a List:

 (+ 2.56 8.54)

The procedure “+” will then operate on the arguments 2.56 and 8.54 to produce 11.1. A bunch of procedures which work together are a program. More examples of lists are the following:

 (+ 2 2)
 (* 103 346)
 (/ 35 46)

If you have XLisp try typing these in yourself. The answers are produced when the carriage return is made, then displayed beneath the list. I used bold lettering to indicate the output.

 (+ 2 2)
 4

See. Isn’t that easy? Lets make things more interesting. Procedures can also be more complex, e.g. MIN and MAX (If you are trying this with XLisp be sure to use the lower case):

 (MIN 53 37 95 23)
 23
 (MAX 74 37 49 20)
 74

MIN will print the smallest argument in the list. MAX will print the largest.

One can also use primitives typically used with multiple arguments with singular arguments.

 (- 7)
 -7
 (- -3)
 3

In the first case the negative or subtract symbol turns the argument into a negative equivalent. In the second the “-” turns the negative argument into a positive just as -1*-3=3.

Lists can contain other lists.

 (- (* 4 9) (+ 8 32))
 -4

The equivalent of the above is as follows:

 (- 36 40)
 -4

As we can see the list is organized and performed in a typical hierarchical manner. A list, therefore, is made up of a left parenthesis, followed by any number of atoms or lists and concluded with a right parenthesis.

Dissecting Lists

Enough of numbers, lets start to use symbols as arguments.

 (A B C)

or

 (Alpha Beta Cookies)

Now lets use more sophisticated procedures. CAR and CDR are used to pull arguments out of lists. I’m told CAR stands for “Contents of Address Register” and CDR stands for “Contents of Data Register”. I’m sure there is some meaning in these titles with regard to the result, but that’s not important right now. What is important is what these procedures do.

(CAR ‘(Alpha Beta Cookies))
 Alpha

CAR returns the first argument in the list. Note that we are using a list in a list.

(CDR ‘(Alpha Beta Cookies))
 (Beta Cookies)

CDR returns the list minus the first argument. What if I am looking for the second argument in a list of three? In this case the CAR and CDR procedures can be nested.

(CAR (CDR ‘(Alpha Beta Cookies)))
 Beta

In the above example CDR produces the list,

 (Beta Cookies)

then CAR produces Beta. I hope you’ve noticed the single quote after the CDR above as well as in the other samples. This is how Lisp knows that the CDR in the above sample is a procedure and not just another argument. Without the single quote the following would be the result:

(CAR (CDR (Alpha Beta Cookies)))
 CDR

CDR in this case was not considered by Lisp as a procedure. The CAR procedure looked to the first argument, in this case the CDR, and displayed it. After playing a bit with these two procedures and a bunch of arguments one can see ways of making sets of procedures which will perform specific kinds of searches.

I’ve tried to give a very brief introduction to Common Lisp simply for the purpose of giving some impression of what Lisp looks like. Most of the above can be done using XLisp. Since Xlisp is an experimental program and Experlisp from Expertelligence will be a relatively serious Lisp development package, this column will probably deal exclusively with Experlisp. Next month The Lisp Listener Window will give a detailed description of Experlisp as well as discuss composing nested CARs and CDRs, symbolic assignment and a whole bunch of related procedures. In future installments I would like to review detailed examples as well as compare the performance of our little Mac to those of the Lisp machines from Xerox and Symbolics.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

FotoMagico 5.6.12 - Powerful slideshow c...
FotoMagico lets you create professional slideshows from your photos and music with just a few, simple mouse clicks. It sports a very clean and intuitive yet powerful user interface. High image... Read more
OmniGraffle Pro 7.12.1 - Create diagrams...
OmniGraffle Pro helps you draw beautiful diagrams, family trees, flow charts, org charts, layouts, and (mathematically speaking) any other directed or non-directed graphs. We've had people use... Read more
beaTunes 5.2.1 - Organize your music col...
beaTunes is a full-featured music player and organizational tool for music collections. How well organized is your music library? Are your artists always spelled the same way? Any R.E.M. vs REM?... Read more
HandBrake 1.3.0 - Versatile video encode...
HandBrake is a tool for converting video from nearly any format to a selection of modern, widely supported codecs. Features Supported Sources VIDEO_TS folder, DVD image or real DVD (unencrypted... Read more
Macs Fan Control 1.5.1.6 - Monitor and c...
Macs Fan Control allows you to monitor and control almost any aspect of your computer's fans, with support for controlling fan speed, temperature sensors pane, menu-bar icon, and autostart with... Read more
TunnelBear 3.9.3 - Subscription-based pr...
TunnelBear is a subscription-based virtual private network (VPN) service and companion app, enabling you to browse the internet privately and securely. Features Browse privately - Secure your data... Read more
calibre 4.3.0 - Complete e-book library...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital librarian... Read more
Lyn 1.13 - Lightweight image browser and...
Lyn is a fast, lightweight image browser and viewer designed for photographers, graphic artists, and Web designers. Featuring an extremely versatile and aesthetically pleasing interface, it delivers... Read more
Visual Studio Code 1.40.0 - Cross-platfo...
Visual Studio Code provides developers with a new choice of developer tool that combines the simplicity and streamlined experience of a code editor with the best of what developers need for their... Read more
OmniGraffle 7.12.1 - Create diagrams, fl...
OmniGraffle helps you draw beautiful diagrams, family trees, flow charts, org charts, layouts, and (mathematically speaking) any other directed or non-directed graphs. We've had people use Graffle to... Read more

Latest Forum Discussions

See All

The House of Da Vinci 2 gets a new gamep...
The House of Da Vinci launched all the way back in 2017. Now, developer Blue Brain Games is gearing up to deliver a second dose of The Room-inspired puzzling. Some fresh details have now emerged, alongside the game's first official trailer. [Read... | Read more »
Shoot 'em up action awaits in Battl...
BattleBrew Productions has just introduced another entry into its award winning, barrelpunk inspired, BattleSky Brigade series. Whilst its previous title BattleSky Brigade TapTap provided fans with idle town building gameplay, this time the... | Read more »
Arcade classic R-Type Dimensions EX blas...
If you're a long time fan of shmups and have been looking for something to play lately, Tozai Games may have just released an ideal game for you on iOS. R-Type Dimensions EX brings the first R-Type and its sequel to iOS devices. [Read more] | Read more »
Intense VR first-person shooter Colonicl...
Our latest VR obsession is Colonicle, an intense VR FPS, recently released on Oculus and Google Play, courtesy of From Fake Eyes and Goboogie Games. It's a pulse-pounding multiplayer shooter which should appeal to genre fanatics and newcomers alike... | Read more »
PUBG Mobile's incoming update bring...
PUGB Mobile's newest Royale Pass season they're calling Fury of the Wasteland arrives tomorrow and with it comes a fair chunk of new content to the game. We'll be seeing a new map, weapon and even a companion system. [Read more] | Read more »
PSA: Download Bastion for free, but wait...
There hasn’t been much news from Supergiant Games on mobile lately regarding new games, but there’s something going on with their first game. Bastion released on the App Store in 2012, and back then it was published by Warner Bros. This Warner... | Read more »
Apple Arcade: Ranked - 51+ [Updated 11.5...
This is Part 2 of our Apple Arcade Ranking list. To see part 1, go here. 51. Patterned [Read more] | Read more »
NABOKI is a blissful puzzler from acclai...
Acclaimed developer Rainbow Train's latest game, NABOKI, is set to launch for iOS, Android, and Steam on November 13th. It's a blissful puzzler all about taking levels apart in interesting, inventive ways. [Read more] | Read more »
A Case of Distrust is a narrative-driven...
A Case of Distrust a narrative-focused mystery game that's set in the roaring 20s. In it, you play as a detective with one of the most private eye sounding names ever – Phyllis Cadence Malone. You'll follow her journey in San Francisco as she... | Read more »
Brown Dust’s October update offers playe...
October is turning out to be a productive month for the Neowiz team, and a fantastic month to be a Brown Dust player. First, there was a crossover event with the popular manga That Time I Got Reincarnated as a Slime. Then, there was the addition of... | Read more »

Price Scanner via MacPrices.net

Score a 37% discount on Apple Smart Keyboards...
Amazon has Apple Smart Keyboards for current-generation 10″ iPad Airs and previous-generation 10″ iPad Pros on sale today for $99.99 shipped. That’s a 37% discount over Apple’s regular MSRP of $159... Read more
Apple has refurbished 2019 13″ 1.4GHz MacBook...
Apple has a full line of Certified Refurbished 2019 13″ 1.4GHz 4-Core Touch Bar MacBook Pros available starting at $1099 and up to $230 off MSRP. Apple’s one-year warranty is included, shipping is... Read more
2019 13″ 1.4GHz 4-Core MacBook Pros on sale f...
Amazon has new 2019 13″ 1.4GHz 4-Core Touch Bar MacBook Pros on sale for $150-$200 off Apple’s MSRP. These are the same MacBook Pros sold by Apple in its retail and online stores: – 2019 13″ 1.4GHz/... Read more
11″ 64GB Gray WiFi iPad Pro on sale for $674,...
Amazon has the 11″ 64GB Gray WiFi iPad Pro on sale today for $674 shipped. Their price is $125 off MSRP for this iPad, and it’s the lowest price available for the 64GB model from any Apple reseller. Read more
2019 15″ MacBook Pros available for up to $42...
Apple has a full line of 2019 15″ 6-Core and 8-Core Touch Bar MacBook Pros, Certified Refurbished, available for up to $420 off the cost of new models. Each model features a new outer case, shipping... Read more
2019 15″ MacBook Pros on sale this week for $...
Apple resellers B&H Photo and Amazon are offering the new 2019 15″ MacBook Pros for up to $300 off Apple’s MSRP including free shipping. These are the same MacBook Pros sold by Apple in its... Read more
Sunday Sale: AirPods with Wireless Charging C...
B&H Photo has Apple AirPods with Wireless Charging Case on sale for $159.99 through 11:59pm ET on November 11th. Their price is $40 off Apple’s MSRP, and it’s the lowest price available for these... Read more
Details of Sams Club November 9th one day App...
Through midnight Saturday night (November 9th), Sams Club online has several Apple products on sale as part of their One Day sales event. Choose free shipping or free local store pickup (if available... Read more
Sprint is offering the 64GB Apple iPhone 11 f...
Sprint has the new 64GB iPhone 11 available for $15 per month for new lines. That’s about 50% off their standard monthly lease of $29.17. Over is valid until November 24, 2019. The fine print: “Lease... Read more
New Sprint November iPhone deal: Lease one iP...
Switch to Sprint and purchase an Apple iPhone 11, 11 Pro, or 11 Pro Max, and get a second 64GB iPhone 11 for free. Requires 2 new lines or 1 upgrade-eligible line and 1 new line. Offer is valid from... Read more

Jobs Board

*Apple* Mobility Pro - Best Buy (United Stat...
**746087BR** **Job Title:** Apple Mobility Pro **Job Category:** Store Associates **Store NUmber or Department:** 000319-Harlem & Irving-Store **Job Description:** Read more
Best Buy *Apple* Computing Master - Best Bu...
**743392BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Store Associates **Store NUmber or Department:** 001171-Southglenn-Store **Job Read more
Best Buy *Apple* Computing Master - Best Bu...
**746015BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Sales **Store NUmber or Department:** 000372-Federal Way-Store **Job Description:** Read more
*Apple* Mobility Pro - Best Buy (United Stat...
**744658BR** **Job Title:** Apple Mobility Pro **Job Category:** Store Associates **Store NUmber or Department:** 000586-South Hills-Store **Job Description:** At Read more
Best Buy *Apple* Computing Master - Best Bu...
**741552BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Sales **Store NUmber or Department:** 000277-Metcalf-Store **Job Description:** **What Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.