TweetFollow Us on Twitter

Neon
Volume Number:1
Issue Number:8
Column Tag:Neon News

"Object Oriented Programming"

By Noel J. Bergman, Software Engineer, MCTel, Inc., MacTutor Contributing Editor

This is the first of a new column object oriented programming. The intent of this first column is to lay the groundwork for object oriented programm-ing, and to review the first object oriented language for the Macintosh, NEON from Kriya. In future columns, we will be using NEON to explore object oriented programming, possibly with short side trips to examine other object oriented languages, if and when they appear.

Why object oriented programming?

As you are all undoubtedly aware, programming the Macintosh is not very easy for most programmers. It is difficult not only for the non-professional programmer: many professionals are having a great deal of trouble dealing with the Macintosh. Most, if not all, of the real problems in dealing with the Macintosh come from the fact that the programs are non-modal. Solutions, such as finite state automata theory, are not well known and produce artificial program constructs. A much better solution is to use object oriented programming.

Historical Perspective

Apple got many of its ideas from the Xerox PARC Smalltalk research group headed by Alan Kay. In fact, a number of that project's members, including Kay himself, are now at Apple. Alan Kay's greatest vision may have been in programming philosophy, or methodology. The wonderful user interface envisioned by the PARC group required a new programming methodology to bring it to life. The one they developed, object oriented programming, has influenced every major language developed since that time, most noticably Smalltalk, Ada and Modula-2.

Although a few computer scientists have been aware of, and applying, object oriented programming for years, the Macintosh has brought home to Apple and thousands of other programmers, the necessity of teaching and learning these techniques.

What is Object Oriented programming?

By now, you are probably wondering what object oriented programming means. What it means is that you define classes of objects, and methods that act upon them. You declare objects to be of a certain class and act upon them by using the methods provided. No access to their internal structure is permitted. You create subclasses, which inherit their storage and methods from their superclass, and may provide additional local storage and methods that add to or replace those inherited from their superclass . A concrete example of this is the Macintosh window, which is a subclass of a QuickDraw grafport, and has additional fields and methods.

This technique allows us to start with a generic application, and to add the subclasses and methods to implement our own unique application.

In a true object oriented programming language, applications are written by creating objects that communicate by sending messages to other objects. This message routing mechanism provides us with the power we need to deal with the Macintosh. The objects remember what has happened to them, and what their status is. We send them messages telling them of actions they should perform on themselves.

Only Smalltalk and Neon provide a true object oriented environment. Ada and Modula-2 only provide you with some level of information hiding; algorithms are still written in the classical style.

Neon

This is an attempt at putting a powerful Smalltalk-like language into the Macintosh. Kriya has taken a potent 1000 word FORTH nucleus and added everything necessary for true object oriented programming, i.e. objects (classes, methods, subclasses) and messaging. They have also enhanced the basic FORTH language with all sorts of nice features for programmers, such as local variables and named parameters. Much of the bite of having to deal with FORTH's simple minded stack is gone, so those of us that dislike FORTH intensely, can enjoy NEON immensely.

NEON does everything one needs to make a standalone (i.e. double-click to start) Macintosh application. Access to the full Macintosh toolbox is there, plus object classes that provide higher level access to most Macintosh objects, e.g. windows.

The documentation for NEON is outstanding. From the begining they acknowledge that object oriented programming is a new concept to most NEON purchasers. Danny Goodman, author of a number of Apple related books and articles, has written a 19 chapter NEON tutorial, which takes you throught NEON's object oriented nature, and the FORTH concepts necessary to write NEON prgorams, step by step.

Also in the Tutorial binder, is a section that describes the NEON system in detail, from the menu bar to putting together a finished NEON application.

A second binder, the reference manual, details every class, and its methods, included with the NEON system. A glossary of all the FORTH and NEON words rounds out the NEON documentation.

In the event that you want even more documentation for NEON, Kriya has provided the source for most the the NEON system above the basic FORTH kernel, as well as an additional complete application.

FORTH compatibility

According to Kriya, NEON will run most FORTH-83 programs with little or no changes. The FORTH heritage of NEON is apparent in its speed, also. Since my Lisa runs at 5 mhz, Kriya provided the Macintosh sieve benchmark of 3 seconds.

Future NEON features

Kriya has several enhancements that they intend to provide over the next 6 months or so. In no particular order, they are:

1. An integrated assembler. (June-ish; right now one could write CODE words by hand assembly. Header and Footer words are provided.)

2. SANE class - objects that implement Apple's SANE floating point standard.

3. Multi-tasking. They already provide two methods for achieving this, which we'll explore in future columns.

4. Memory manager - Kriya says that the Macintosh memory manager is not ideally suited to object oriented programming. A more suitable memory management scheme may be forthcoming if there is user interest.

5. Additional machines - Kriya intends to port NEON to other machines, such as the Amiga. This would give Macintosh/NEON programmers a very fast route into that market.

Kriya plans to provide quarterly updates. For this service they will be charging a $50/year service and update charge. Comparing this to the per/update charge of other firms, this is a reasonable method. They are also extremely interested in user feedback on what enhancements are desired. A library of user developed object classes is also being actively pursued. Users who take the time to add or enhance object classes for more Macintosh objects, or general purpose objects, are encouraged to submit them to Kriya for inclusion in the library.

NEON Pricing

Right now, NEON is $155 direct from Kriya (they will NOT sell through dealers). After June 30th, the price will go up, although final price has not been established, regardless of what the ads currently say. If a computer club registers itself with Kriya, then the club will receive a $15 rebate for every copy of NEON purchased by one of its members.

Blemishes

NEON is a fine, solid product. However, there are a few blemishes on a otherwise highly polished package. Most of these are minor, such as forgetting to turn on the cursor when the system starts (the word +curs will fix that), forgetting to disable the ineffective EDIT menu items, the fact that the rather nice editor is sometimes slow since it wordwraps, and a few other minor things.

However, despite the fact that I was able to compile a full page of such minor details, I only found a single major defect. Even when I deliberately created a system error, the bomb box provided a resume button; more importantly the resume button actually worked!

The one defect is that shows up in several areas. You must close the NEON editor desk accessory before you quit NEON, otherwise NEON will crash the next time you run it. Likewise, if you try to run NEON under the Switcher 2.0, or after using the MDS editor (EDIT), it will crash. The solution is to reset the Macintosh if you have been using EDIT.

Interestingly, the NEON kernel will run; it is the programmer's interface to the kernel, NEON.COM, that seems to cause the problem. Kriya is aware of, and is fixing the problem.

Other Object Oriented Development Environments

NEON is here, today, and works wonderfully. This diehard Pascal, and anti-FORTH, programmer is currently designing some sizeable NEON applications. However, for those of you who don't want to use NEON, there will be alternative object oriented systems available before 1986.

Apple will release new object oriented programming environments this year, which are designed to help produce productive Macintosh programmers.

MacAPP

This Macintosh version of the Lisa Toolkit is due out sometime during the summer. It is a generic Macintosh application written in Object Pascal, an extention of Pascal to support object oriented programming. Apple worked closely with Prof. Wirth to design the new language extentions. Other versions of MacAPP might be available in Smalltalk, Objective C, or maybe NEON.

Smalltalk

The grandfather of the object oriented languages is available from Apple for $45. The catch is that this version is probably a year away from the general public, and requires a megabyte of RAM and a harddisk to run. It is also completely unsupported, and just about undocumented.

Sieve vs Sieve (MacFORTH vs NEON)

There has been some confusion regarding sieve times in NEON. Evidently, the original sieve figure of 3 seconds for NEON was based upon a single iteration of the sieve algorithm. As most people know, the times should be reported for 10 interations of the algorithm. While preparing a true sieve benchmark for NEON, I came across a number of interesting items.

MacFORTH, as reviewed in The Club Mac News (July 1984), comes with a sieve program. There are two things wrong with this program as distributed. First, the implementation of the sieve algorithm is different from that in the Jan '83 issue of BYTE; in fact the MacFORTH program runs almost twice as fast as the BYTE program, in both MacFORTH and NEON.

Converting the MacFORTH program to NEON brought home another problem; NEON is based upon the FORTH-83 standard, whereas MacFORTH is based on the FORTH-79 standard. For example, the CREATE FLAGS statement has different meanings. In FORTH-79, the CREATE statement is roughly equivalent to the VARIABLE statement (with subtle differences for ROM environments), whereas in FORTH-83 it is used to prepare code word definitions.

Second, the sieve program caught the first documented bug in the NEON kernel. The ic! word is "dead meat"; use i c! instead.

( SIEVE #1 - BYTE MAGAZINE JAN '83) 
(MacFORTH 41 seconds, NEON 42 seconds )

8190 constant size
0 variable flags size allot

: do-prime
    flags size 1 fill
    0 size 0
    do flags i + c@
        if i dup + 3 + dup i +
            begin dup size <
            while 0 over flags + c! over + repeat
            drop drop 1+
        then
    loop
    . ." primes" cr
;

: sieve 10 0 do do-prime loop ." Done." cr ;


( SIEVE #2 - MacFORTH distribution)
(MacFORTH 26 seconds, NEON 25 seconds )

8190 constant size
0 variable flags size allot

: primes flags size 1 fill
    0
    size 0 do
        flags i+ c@ if
        3 i+ i+ dup i+
        size < if
        size flags + over i+ flags + do
            0 i c! dup
            +loop
            then drop 1+
        then
    loop
    . ." primes "
;

: sieve 10 0 do primes loop ." Done." cr ;

SCREENBITS: a difference in philosophies

The Mac XL was not designed to be turned on and off continually. In fact, the owner's manuals suggests that it be left on continually, unless it will be unattended for a few days. That is one of the reasons behind the automatic screen dimming; to ensure the long life of the screen. Unfortunately, under MacWORKS, the screen doesn't dim as completely as I would like it to dim.

The first program that I had written on the old Pascal Workshop 2.0 was a program to turn the display completely off. I was in the process of dedicating the internal hard disk to the MacWORKS environment when I got NEON, and decided to use NEON to produce a similar program for MacWORKS. Since I didn't have access to the video level from MacWORKS, I decided just to paint the screen black.

The program, BLACKOUT, illustrates a number of useful concepts. Kriya never assumed that people would use QuickDraw Grafports other than in windows, and didn't provide for their separate initialization. Since windows are behind the menu bar, the menu bar would be visible; thus raw access to a grafport was needed. A new subclass of grafport, VIEWPORT, was created to add the additional messages required.

Also, like all good Macintosh programs, the program is independent of screen size and memory locations.. Lisa Pascal provides a pre-declared Quickdraw rectangle constant, SCREENBITS, whose bounds can be checked for the screen size. In other languages, we must get this information from the quickdraw globals area of memory. The SCREENBITS word , illustrates how one would gain access to a great many global variables, in the properly generic Macintosh way. We find this area of memory by tracing through a series of pointers headed by the current value of the A5 register. This value of this register is kept in a system global in low memory (hex address 904).

All addresses in NEON are relative to a base value. This value is in register A3. Thus, 904 @ would fetch the value at 904 + the contents of A3. The -base word is used to convert from NEON relative addresses to absolute addresses. 904 -base @ fetches the value at absolute address 904.

SCREENBITS was written on the first day I received NEON, and reflects some initial stylistic residue from my limited FORTH background. Reese Warner of Kriya provided an alternative, albiet uncommented, definition that is more representative of proper NEON style. Note the use of local variables. As stated in the NEON manual, the format is

{ [any named parameters] \ [any local vars] -- stack comment }

The BLACKOUT program also shows how easily one can use the toolbox from NEON. Stack based toolbox routines are simply accessed by setting the stack (NEON supplies pack and unpack words for converting from NEON's 32 bit wide integers to the toolbox's 16 bit wide integers). Register based toolbox routines are only slightly more complicated, and will be fully covered next month, when we start to work with the Mac's modem port.

( Blackout - Paints the entire Macintosh)
(screen black and waits for <cr> )

( ViewPort is a subclass of GrafPort)
(that can initialize and paint )

:CLASS  ViewPort  <Super GrafPort

  ( -- ) ( Initialize the grafport structure )
  :M  NEW:     (abs) call OpenPort ;M

  ( -- ) ( Paint the whole grafport rectangle )
  :M  Paint:   paint: PortRect ;M

;CLASS 

ViewPort Port

( Two definitions of SCREENBITS) 
(are provided; edit one of them out for use )

: ScreenBits
    $ 904 -base @ ( currentA5 -- )
    -base @       ( <address of quickdraw globals> --)
    $ FFFFFF86 +  ( <address of screenbits> -- )
    $ 6 +         ( <address of bounds rect> -- )
    dup           ( adr adr -- )
    -base @       ( adr <first point>  -- )
    unpack        ( adr l t  -- )
    rot           ( l t adr -- )
    $ 4 +         ( l t <adr of second point> -- )
    -base @       ( l t point -- )
    unpack        ( l t r b )
;

( Alternative method - uses local variables )
: ScreenBits { \ QDGlobals RectAddr 
top left bot right -- l t r b }
    $ 904 -base @ -base @ -> QDGlobals
    QDGlobals 116 - -base -> RectAddr
    RectAddr @ unpack -> top -> left
    RectAddr 4+ @ unpack -> bot -> right
    left top right bot
;


( WaitCR - waits for a <cr> )
: WaitCR BEGIN $ 0D key = UNTIL ;

( hidemouse - hides the cursor )
: HideMouse call HideCursor ;

( showmouse - shows the cursor )
: ShowMouse call ShowCursor ;

( BlackOut - the word that starts it all )
: BlackOut
    HideMouse           
( hide the mouse so its outline is gone )
    SavePort            
( Save the old grafport - standard Mac behavior )
    New: Port           
( initialize our grafport )
    ScreenBits PutRect: Port  
( and make it the FULL screen size )
    Paint: Port         
( paint the screen black )
    WaitCR              
( wait until the user types a <cr> )
    ShowMouse           
( restore the mouse )
    RestPort            
( restore the old grafport when done - again, SOP )
    Bye                 
( exit back to the finder )
;

Technical Tidbits

The first NEON update disk is almost ready. It should contain classes for SANE variables, sorting, linked lists, 2-d arrays, symbol tables, and other goodies. The Macintosh Developer's SIG of the Philadelphia Area Computer Society is also starting to get into NEON in a big way, and a number of members have mentioned some of the more interesting classes that they are developing for the public domain.

Also from a recent PACS meeting, came a fascinating idea. A member wanted to know how to link in separately compiled object code with NEON programs. My solution: write a NEON definition to load the code resource from disk, branch subroutine to it, and then properly return to NEON with a next,. This could be done under the current system, or with the NEON assembler being developed. If there is some additional interest in this technique, I could demonstrate it in a later article.

From the Mountain

I have a tentative arrangement with Kriya to provided me with a list of the most frequent questions and answers from NEON technical support. These questions and answers will be published in MacTutor as a form of published technical support. Here are some of this month's solutions to problems:

1. Quickdraw pictures are easy to use from NEON, as the following code illustrates:

 " Scrapbook File" openResFile   ( open resource)
 picture myPic                  ( declare a pic object )
 res# init: mypic                ( resource number )
 getnew: mypic                 ( read it in )
 100 100 goto: mypic       ( position it )
 draw: mypic                    ( exercise for the reader )

2. NEON works with standard text files. None of this FORTH screen nonsense.

3. The Clipboard. NEON has a serious problem with the clipboard. For some reason, whenever you use it, the next time you run NEON, it crashes. This problem prevents NEON from running under Switcher, and from running after Edit has been used. Kriya is aware of this problem, and should fix it soon. Interestingly, the problem does not show up in the kernel, only in the user frontend.

Next Month

Starting in the next issue of MacTutor, we will develop a graphics oriented modem program. This month's column is intentionally short so that we could include the description of Scott Watson's protocol, which is built into Red Ryder with this article. We'll define the problem, the necessary classes, and start to develop them next month.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

MTR 5.0.0.1 - The Mac's oldest and...
MTR (was MacTheRipper)--the Mac's oldest and smartest DVD-backup app--is now updated to version 5.001 MTR -- the complete toolbox, not a one-trick, point-and-click extractor. MTR is intended for... Read more
LibreOffice 4.4.5.2 - Free, open-source...
LibreOffice is an office suite (word processor, spreadsheet, presentations, drawing tool) compatible with other major office suites. The Document Foundation is coordinating development and... Read more
Adobe Lightroom 6.1.1 - Import, develop,...
Adobe Lightroom is available as part of Adobe Creative Cloud for as little as $9.99/month bundled with Photoshop CC as part of the photography package. Lightroom 6 is also available for purchase as a... Read more
File Juicer 4.41 - Extract images, video...
File Juicer is a drag-and-drop can opener and data archaeologist. Its specialty is to find and extract images, video, audio, or text from files which are hard to open in other ways. It finds and... Read more
A Better Finder Rename 9.52 - File, phot...
A Better Finder Rename is the most complete renaming solution available on the market today. That's why, since 1996, tens of thousands of hobbyists, professionals and businesses depend on A Better... Read more
OmniFocus 2.2.3 - GTD task manager with...
OmniFocus helps you manage your tasks the way that you want, freeing you to focus your attention on the things that matter to you most. Capturing tasks and ideas is always a keyboard shortcut away in... Read more
TinkerTool 5.4 - Expanded preference set...
TinkerTool is an application that gives you access to additional preference settings Apple has built into Mac OS X. This allows to activate hidden features in the operating system and in some of the... Read more
Tinderbox 6.3.1 - Store and organize you...
Tinderbox is a personal content management assistant. It stores your notes, ideas, and plans. It can help you organize and understand them. And Tinderbox helps you share ideas through Web journals... Read more
Parallels Desktop 10.2.2 - Run Windows a...
Parallels Desktop is simply the world's bestselling, top-rated, and most trusted solution for running Windows applications on your Mac. With Parallels Desktop for Mac, you can seamlessly run both... Read more
Adobe Premiere Pro CC 2015 9.0.1 - Digit...
Premiere Pro CC 2015 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Premiere Pro customer). Premiere Pro CS6 is still available for... Read more

You Against Me (Games)
You Against Me 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: A simple game… You. Me. Claim, steal, lock, score, win! | Read more »
Yep, it's True - Angry Birds 2 is O...
The not exactly rumors were true and the birds are back. Angry Birds 2 has come to the App Store and the world will... well I suppose it'll still be the same, but now we have more bird-flinging options! [Read more] | Read more »
You Could Design Your Own Card for Chain...
If you've ever wanted to create your own item, weapon, trap, or even monster for Chainsaw Warrior: Lords of the Night, this is your chance. Auroch Digital is currently holding a contest so that fans can fight to the death (not really) to see which... | Read more »
Bitcoin Billionaire is Going Back in Tim...
If you thought you managed to buy everything there is to buy in Bitcoin Billionaire and make all the money, well you though wrong. Those of you who made it far enough might remember investing in time travel - and it looks like that investment is... | Read more »
Domino Drop (Games)
Domino Drop 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Domino Drop is a delightful new puzzle game with dominos and gravity!Learn how to play it in a minute, master it day by day.Your... | Read more »
OPERATION DRACULA (Games)
OPERATION DRACULA 1.0.1 Device: iOS Universal Category: Games Price: $5.99, Version: 1.0.1 (iTunes) Description: 25% off launch sale!!! 'Could prove to be one of the most accurate representations of the Japanese bullet hell shmup... | Read more »
Race The Sun (Games)
Race The Sun 1.01 Device: iOS iPhone Category: Games Price: $4.99, Version: 1.01 (iTunes) Description: You are a solar craft. The sun is your death timer. Hurtle towards the sunset at breakneck speed in a futile race against time.... | Read more »
Tap Delay (Music)
Tap Delay 1.0.0 Device: iOS Universal Category: Music Price: $4.99, Version: 1.0.0 (iTunes) Description: Back in the “old days”, producers and engineers created delay and echo effects using tape machines. Tap Delay combines the warm... | Read more »
This Week at 148Apps: July 20-24, 2015
July is Heating Up With 148Apps How do you know what apps are worth your time and money? Just look to the review team at 148Apps. We sort through the chaos and find the apps you're looking for. The ones we love become Editor’s Choice, standing out... | Read more »
Red Game Without A Great Name (Games)
Red Game Without A Great Name 1.0.3 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.3 (iTunes) Description: The mechanical bird is flying through an unfriendly, Steampunk world. Help it avoid obstacles and deadly... | Read more »

Price Scanner via MacPrices.net

Apple’s Education discount saves up to $300 o...
Purchase a new Mac or iPad at The Apple Store for Education and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free,... Read more
12-inch MacBooks in stock for $20 off, save o...
Adorama has 12″ Retina MacBooks in stock for $20 off MSRP including free shipping plus NY & NJ sales tax only. For a limited time, Adorama will include a free Apple USB-C to USB Adapter, free 4-... Read more
College Student Deals: Additional $100 off Ma...
Take an additional $100 off all MacBooks and iMacs at Best Buy Online with their College Students Deals Savings, valid through August 8, 2015. Anyone with a valid .EDU email address can take... Read more
2015 13-inch 2.7GHz Retina MacBook Pro on sal...
B&H Photo has the new 2015 13″ 2.7GHz/128GB Retina MacBook Pro on sale today for $1199 including free shipping plus NY sales tax only. Their price is $100 off MSRP. Read more
2.8GHz Mac mini available for $988, includes...
Adorama has the 2.8GHz Mac mini available for $988, $11 off MSRP, including a free copy of Apple’s 3-Year AppleCare Protection Plan. Shipping is free, and Adorama charges sales tax in NY & NJ... Read more
Updated Mac Price Trackers
We’ve updated our Mac Price Trackers with the latest information on prices, bundles, and availability on systems from Apple’s authorized internet/catalog resellers: - 15″ MacBook Pros - 13″ MacBook... Read more
High-Precision Battery Fuel Gauge IC Extends...
Renesas Electronics Corporation has announced its new lithium-ion (Li-ion) battery fuel gauge IC, the RAJ240500, designed to extend battery life for connected mobile devices such as tablets, notebook... Read more
27-inch 3.3GHz 5K iMac on sale for $1799, $20...
B&H Photo has the 27″ 3.3GHz 5K iMac on sale for $1799 including free shipping plus NY tax only. Their price is $200 off MSRP, and it’s the lowest price available for this model from any Apple... Read more
Twelve South Free Dual Screen Backgrounds Co...
Twelve South has posted a second collection of travel Desktop photos, noting: For the Twelve South team, a vacation is never just a vacation. It’s a time to try out new prototypes on the road, visit... Read more
Apple Refurbished iMacs available for up to $...
The Apple Store has Apple Certified Refurbished iMacs available for up to $380 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free: - 27″ 3.5GHz 5K iMac – $1949 $... Read more

Jobs Board

Engineering Manager, Search Relevance, *Appl...
**Job Summary** Apple 's new Spotlight Suggestions service provides fast, relevant search results from the Inte et in Spotlight and Safari on iOS and OS X. We are looking Read more
Lead Infrastructure Engineer - *Apple* /Mac P...
…of a team * Requires proven problem solving skills Preferred Additional: * Apple Certified System Administrator (ACSA) * Apple Certified Technical Coordinator (ACTC) Read more
*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales. Specialist - Retail Customer Service and Sales. Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales. Specialist - Retail Customer Service and Sales. Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.