TweetFollow Us on Twitter

NeXT Evolution
Volume Number:5
Issue Number:7
Column Tag:Developer's Forum

NeXT Evolution

By Paul Snively, Contributing Editor, Wheeling, IL

Evolution

Those of you who are waiting for the next (NeXT?) revolution in microcomputing are likely to be disappointed lately, and are probably going to remain that way for some time to come. That’s the news that I have to offer now that I have access to a NeXT computer. Before you go jumping out of your office windows or selling off your worldly goods and waiting for the end of the world to arrive, let me quickly add that this doesn’t mean that the picture is bleak. Far from it. Let me explain:

There’s a cube sitting about ten feet away from me. I won’t bore you with digitized pictures or a gushing description of how sexy it is; we’ve all seen the pictures, and we all know how sexy basic black can be (a fact that’s never been lost on the fashion world). The fact of the matter is that there are probably a fair number of people in MacTutor’s readership who remain without hands-on experience with this particular cube and would like some ideas from a fellow Macintosh developer as to just what this enigmatic little machine is like.

This Baby Ain't Portable!

For starters, the machine is, well, enigmatic. If you ever have to carry one of these things, the first thing that you realize is that the MegaPixel display that ships standard with every machine is far, far heavier than the computer itself is. Aside from that, there are virtually no physical problems with the machine. Putting one together is a simple matter of plugging the keyboard and mouse into the monitor, running a large cable between the computer and the monitor, and plugging the computer into the wall. Oh, by the way, you can plug the computer into the wall in the United States, England, Germany, or most other European countries with equal facility and no converters necessary.

25 mHz 68030 Processor

The computer itself, from an internal standpoint, is something of a throwback to a bygone era, at least in the microcomputer world: the case is simply a card cage. It consists of a power supply, an optical disk drive, optionally an internal Winchester hard disk, and a single card that literally can be described as the motherboard. The motherboard contains the obvious things: a 25 mHz MC68030 microprocessor, a similarly-clocked MC68882 floating-point coprocessor, and the by-now-famous Motorola DSP (Digital Signal Processor) chip. There are also two rather large custom VLSI chips that provide the I/O throughput that NeXT is so proud of. There’s also on-board Ethernet support for the thin-wire connector that sits on the backplane of every machine (and you thought AppleTalk on every machine was something).

Most of us are at least in touch with the hardware specs for the machine, and those who weren’t are now, after just two paragraphs of my lurid prose, so I’d better get to the point, which is this: the NeXT computer is a very nice 68030-based low-end workstation that supports a very nice version of UNIX (it’s Carnegie-Mellon’s MACH operating system, which consists of a rather small, tight kernel that provides a few new wrinkles in terms of memory management, networking, and multiprocessing, but manages to be compatible at the OS call level, not just the user level, with BSD4.3 UNIX). On top of MACH is Display Postscript, with a few NeXT wrinkles, such as fast bitmap compositing, thrown in for good measure (actually, even bitmap compositing isn’t entirely NeXT’s; it was jointly developed with Steve Jobs’ other little company, Pixar. By the way, if Pixar isn’t doing a chipset/card for the NeXT computer that’ll turn it into one of the hottest graphic workstations around, I’ll eat my shirt).

Ok, so we have what, from almost all outside appearances, is a 68030-based UNIX box running Display Postscript. Now what?

An Object-Oriented Computer From Ground Up!

“Now what” is what this article is really about. Because the reason that the NeXT computer is a piece of evolution that we should all be paying attention to as developers has nothing to do with the 68030, with the DSP, with optical storage, with UNIX or MACH, or any of that. It comes down to this:

The NeXT computer is an object-oriented computer almost from the ground up. Every machine ships with Stepstone, Inc.’s Objective-C, and the Free Software Foundation’s gcc (the GNU C compiler), gdb (GNU C source-level debugger), and GNU EMACS (as well as the Berkeley standard vi editor and NeXT’s own “Edit,” which is--as you might have guessed--a simple multi-window text editor based on NeXT’s windowing system, Display Postscript, etc.)

It doesn’t stop there. Each and every machine includes the Application Toolkit. The only way that I can describe the AppKit, as it’s called by NeXT, is that it’s what MacApp should have been. Again, this is nothing radical or new; it’s just the NeXT evolutionary step along the road that MacApp paved. The AppKit has a relatively small number of classes, and the hierarchy is fairly straightforward. The AppKit does what the AppKit should do: it makes the process of writing a NeXT application as painless as programming such a machine should be.

The reason that it’s so painless, however, is only partially a function of using Objective-C and the AppKit. The other important element in the development-tool arena is the Interface Builder.

Now, judging from the name alone, you wouldn’t think that the Interface Builder is anything special. In fact, it sounds an awful lot like ResEdit, doesn’t it? After all, ResEdit is a nice interactive utility for creating things that are, by and large, human interface elements, such as windows, dialog boxes, menus, strings, string lists, and the like. Certainly Interface Builder does all of these things, but more importantly, Interface Builder has some smarts about Objective-C and the AppKit. You can build dialogs in Interface Builder in the way you’d expect--by dragging buttons, sliders, fields, etc. to a window--but once you’ve done that, you can go a step or two further.

Interface Builder knows about objects that are part of the AppKit. It knows that applications have a main window and a main menu. It knows that there may be other windows, and submenus attached to the main menu. It knows about the standard behaviors that the AppKit defines for these objects (for example, it knows that when you click a button, the button should send some message to an object).

Non-human-interface objects--any object that isn’t part of the AppKit, in fact--Interface Builder knows nothing about by default. However, you can specify any custom object to Interface Builder, describing its methods in just enough detail to allow Interface Builder to use them in the process of connecting things.

To use a trivial example, let’s convert degrees Celsius to degrees Fahrenheit. To do this, we probably want a dialog that contains two text fields, Celsius and Fahrenheit, and a button, which we’ll title “>>Convert>>” to highlight the fact that we’re converting from Celsius to Fahrenheit.

All that we have to do to create this dialog is to drag two text fields and a button to our application’s main window. We should lay things out appropriately and label the fields and button appropriately. Then what we need to do is define a custom object, called “Converter,” to the Interface Builder. Converter isn’t a user-interface object--it’s the object that actually does the computation. It will only have one method, “convert,” which will take zero parameters, and it will have two “outlets,” input and output.

Outlets are the means by which non-user-interface objects communicate with user-interface objects. An outlet is an instance variable that an object possesses that gets initialized to the id of some other object so that the object owning the outlet can send messages to the other object. In this case, we will use the Interface Builder to connect the Celsius field to the Input outlet and the Fahrenheit field to the Output outlet. This way Converter’s convert method can refer to Input and Output to do the job without worrying about exactly what the objects being referred to are--Input could, after all, be connected to some object that provides a C-language-style float value based on a signal from an A/D converter attached to some sensor somewhere. Converter and its convert method shouldn’t--and don’t--care.

By now you may be wondering how all these connections are made. The Interface Builder includes a Connect panel that has square recessions to contain the sender object, the receiver object, and the outlet object. There are also two scrolling fields above the recessions. First, you would drag the button object to the sender recession and the Converter object to the receiver recession. The left-most scrolling text field would then list all of the messages that the Converter understand. We defined it to only understand one, convert. Clicking on that line in the scrolling field will cause a cable to appear between the button object and the Converter object, with separated screw and tab connectors in between. Clicking the cable closes the connection, indicating that clicking the button will send the convert message to the Converter object.

The right-most scrolling text field will list the outlets for the Converter object. Again, we defined two, Input and Output. We would drag the Celsius field to the outlet recession, then click on the line showing Input. A cable with separated male and female connectors would appear between the Converter object and the Celsius field. Clicking the cable would indicate that we want the Input instance variable initialized to refer to the Celsius text field in our dialog. We would repeat the process for the Fahrenheit field, connecting it to the Output outlet (read “instance variable.”)

It’s unfortunate that I can’t include NeXT screen dumps in this article; this whole process requires far too much verbiage to describe. Everything I’ve discussed so far can be done in Interface Builder in considerably less than sixty seconds. All that remains, then, is to save your work in Interface Builder and actually sit down and write the code for the Converter object.

I won’t go into massive details of the syntax and concepts behind Objective-C here, partially because this isn’t the time or place, and partially because my understanding of both is extremely incomplete at this point. In any case, the process consists of creating a new class, Converter, that will simply be a subclass of Object, since it doesn’t need to inherit anything special from anything else. Converter would have two instance variables, Input and Output, both of type id (all objects in Objective-C are of type id). We would then define the single method, convert. Convert will have two local variables of type float, c and f. The code for convert would then look something like this:

c = [Input getFloatValue];
f = (c *9.0 / 5.0) + 32.0;
[Output setFloatValue: f];
return(self);

Apart from declaring the class and its instance variables and the method and its local variables, that is all there is to converting from celsius to fahrenheit at literally the click of a button. The Interface Builder prevents you from having to write any more code than that to make your application work.

The question I have is this: why hasn’t anyone done anything like that for MacApp? Certainly parsing and generating Object Pascal code with some amount of “inside knowledge” of MacApp shouldn’t be that tough; anyone who’s ever used compiler-development tools such as yacc and lex knows that. Let’s not let this piece of evolution pass us by. With tools like this, programming can become much easier for all of us.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Latest Forum Discussions

See All

Six fantastic ways to spend National Vid...
As if anyone needed an excuse to play games today, I am about to give you one: it is National Video Games Day. A day for us to play games, like we no doubt do every day. Let’s not look a gift horse in the mouth. Instead, feast your eyes on this... | Read more »
Old School RuneScape players turn out in...
The sheer leap in technological advancements in our lifetime has been mind-blowing. We went from Commodore 64s to VR glasses in what feels like a heartbeat, but more importantly, the internet. It can be a dark mess, but it also brought hundreds of... | Read more »
Today's Best Mobile Game Discounts...
Every day, we pick out a curated list of the best mobile discounts on the App Store and post them here. This list won't be comprehensive, but it every game on it is recommended. Feel free to check out the coverage we did on them in the links below... | Read more »
Nintendo and The Pokémon Company's...
Unless you have been living under a rock, you know that Nintendo has been locked in an epic battle with Pocketpair, creator of the obvious Pokémon rip-off Palworld. Nintendo often resorts to legal retaliation at the drop of a hat, but it seems this... | Read more »
Apple exclusive mobile games don’t make...
If you are a gamer on phones, no doubt you have been as distressed as I am on one huge sticking point: exclusivity. For years, Xbox and PlayStation have done battle, and before this was the Sega Genesis and the Nintendo NES. On console, it makes... | Read more »
Regionally exclusive events make no sens...
Last week, over on our sister site AppSpy, I babbled excitedly about the Pokémon GO Safari Days event. You can get nine Eevees with an explorer hat per day. Or, can you? Specifically, you, reader. Do you have the time or funds to possibly fly for... | Read more »
As Jon Bellamy defends his choice to can...
Back in March, Jagex announced the appointment of a new CEO, Jon Bellamy. Mr Bellamy then decided to almost immediately paint a huge target on his back by cancelling the Runescapes Pride event. This led to widespread condemnation about his perceived... | Read more »
Marvel Contest of Champions adds two mor...
When I saw the latest two Marvel Contest of Champions characters, I scoffed. Mr Knight and Silver Samurai, thought I, they are running out of good choices. Then I realised no, I was being far too cynical. This is one of the things that games do best... | Read more »
Grass is green, and water is wet: Pokémo...
It must be a day that ends in Y, because Pokémon Trading Card Game Pocket has kicked off its Zoroark Drop Event. Here you can get a promo version of another card, and look forward to the next Wonder Pick Event and the next Mass Outbreak that will be... | Read more »
Enter the Gungeon review
It took me a minute to get around to reviewing this game for a couple of very good reasons. The first is that Enter the Gungeon's style of roguelike bullet-hell action is teetering on the edge of being straight-up malicious, which made getting... | Read more »

Price Scanner via MacPrices.net

Take $150 off every Apple 11-inch M3 iPad Air
Amazon is offering a $150 discount on 11-inch M3 WiFi iPad Airs right now. Shipping is free: – 11″ 128GB M3 WiFi iPad Air: $449, $150 off – 11″ 256GB M3 WiFi iPad Air: $549, $150 off – 11″ 512GB M3... Read more
Apple iPad minis back on sale for $100 off MS...
Amazon is offering $100 discounts (up to 20% off) on Apple’s newest 2024 WiFi iPad minis, each with free shipping. These are the lowest prices available for new minis among the Apple retailers we... Read more
Apple’s 16-inch M4 Max MacBook Pros are on sa...
Amazon has 16-inch M4 Max MacBook Pros (Silver and Black colors) on sale for up to $410 off Apple’s MSRP right now. Shipping is free. Be sure to select Amazon as the seller, rather than a third-party... Read more
Red Pocket Mobile is offering a $150 rebate o...
Red Pocket Mobile has new Apple iPhone 17’s on sale for $150 off MSRP when you switch and open up a new line of service. Red Pocket Mobile is a nationwide MVNO using all the major wireless carrier... Read more
Switch to Verizon, and get any iPhone 16 for...
With yesterday’s introduction of the new iPhone 17 models, Verizon responded by running “on us” promos across much of the iPhone 16 lineup: iPhone 16 and 16 Plus show as $0/mo for 36 months with bill... Read more
Here is a summary of the new features in Appl...
Apple’s September 2025 event introduced major updates across its most popular product lines, focusing on health, performance, and design breakthroughs. The AirPods Pro 3 now feature best-in-class... Read more
Apple’s Smartphone Lineup Could Use A Touch o...
COMMENTARY – Whatever happened to the old adage, “less is more”? Apple’s smartphone lineup. — which is due for its annual refresh either this month or next (possibly at an Apple Event on September 9... Read more
Take $50 off every 11th-generation A16 WiFi i...
Amazon has Apple’s 11th-generation A16 WiFi iPads in stock on sale for $50 off MSRP right now. Shipping is free: – 11″ 11th-generation 128GB WiFi iPads: $299 $50 off MSRP – 11″ 11th-generation 256GB... Read more
Sunday Sale: 14-inch M4 MacBook Pros for up t...
Don’t pay full price! Amazon has Apple’s 14-inch M4 MacBook Pros (Silver and Black colors) on sale for up to $220 off MSRP right now. Shipping is free. Be sure to select Amazon as the seller, rather... Read more
Mac mini with M4 Pro CPU back on sale for $12...
B&H Photo has Apple’s Mac mini with the M4 Pro CPU back on sale for $1259, $140 off MSRP. B&H offers free 1-2 day shipping to most US addresses: – Mac mini M4 Pro CPU (24GB/512GB): $1259, $... Read more

Jobs Board

All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.