TweetFollow Us on Twitter

MCL3 Review
Volume Number:11
Issue Number:9
Column Tag:Object-Oriented Languages

Macintosh Common Lisp 3.0

An Old Language is New Again!

By Rich Parker, Modesto, CA

Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.

MCL: The Rumor and The Truth

For a while last year we all thought that Macintosh Common Lisp (MCL) was going to be abandoned. Apple had decided not to continue development of the product and there was no suitable replacement in sight, particularly for the new PowerMac computers. But Apple finally decided to sell the product to Digitool, Inc. Digitool started right off by commencing the development of two new versions of the product; the first is the new 68K version 3.0 (which, unlike the previous version 2.0.1 runs just fine on the PowerMac with the Modern Memory Manager enabled). Digitool is also working on a PowerMac native version of the product, which they say will be released later this year.

Creating the PowerMac version is a fairly major undertaking, mainly because MCL contains an incremental compiler that generates native 68K code. MCL also relies on the memory management facilities of the 68K family, and supports 68K-style floating-point computations. All of this will have to change for a native PPC version. But Digitool promises that the upcoming PowerMac product will be very efficient and fully compatible with even the latest PowerMac machines.

The truth is that MCL 3.0 is extremely efficient right now, even though it’s running under emulation mode on my PowerMac 6100. It no longer crashes when I have the Modern Memory Manager turned on, and it’s happy to execute with VM turned on as well.

So What Good Is Lisp?

I see many messages from developers who surf the various online networks and it seems that many of these messages are devoted to discussions of the various problems with the C++ language. In fact, many have expressed that C++ is an “abominable” language, full of pitfalls and traps.

But Lisp is not without its own detractors (those who bemoan its copious use of parenthesis), but the fact is that few ever complain about limitations of the language. In fact, Lisp (ANSI Common Lisp, that is) is so full-featured and straightforward that the main body of complaints are focused on the breadth of the language, rather than its limitations - it’s such a large language that learning all of its features is almost impossible. Although the language is said to be quite large, it’s not because of its syntax; that part is simple. The difficulty lies in learning the hundreds of standard functions, macros, and special forms that are documented in the Common Lisp standard.

Once you spend some time with Lisp (and especially MCL), you’ll begin to see the tremendous potential of the language. MCL appears to be interpretive, but it is actually compiling each statement you type into native code (68K code, presently) as it is entered. If a particular set of statements is executed a second time, it is not recompiled, but is executed directly. You can compile individual files of source text and store these into fasl files, which load and execute very efficiently.

You can build an application piece by piece, testing as you go, without having to go through the edit, compile, link, execute cycle that is standard with languages like Pascal, C, and C++. MCL is a prototyper’s dream come true. The language implements the full ANSI Common Lisp standard, including the Common Lisp Object System (CLOS). In addition, MCL contains classes and methods that implement all of the Macintosh user interface features, as well as almost all of the latest features of the Mac OS. The product directly supports interfaces to over 5000 traps, 1000 record definitions, and 13,000 constant definitions, including support for WorldScript, Apple events, Comm Toolbox, QuickDraw GX, QuickTime, and the Apple Open Collaboration Environment (AOCE). It also supports a “Foreign Function” interface that allows you to interface functions written in other languages to your MCL applications. MCL’s current Foriegn Function interface has some limitations (supports only model near) which Digitool reports will be addressed in the PowerPC implementation.

And of course, MCL is a fully object-oriented dynamic language (OODL), so you can create functions that create other functions to your heart’s content. When an object becomes unreferenced, it is disposed and the garbage collector will reuse its memory automatically. All of the latest fascinations in the computer science realm are provided with MCL.

The ease with which applications can be prototyped is one of the major features of the product. Once familiar with the language, you can develop an application prototype in a matter of hours instead of days or weeks. Creating windows, nested views, dialogs, menus, and other Macintosh user interface features is a relatively simple chore. And the interactive debugging tools are also a great help in getting an application written and ready to use.

Just to give you an example of what Lisp code looks like, Listing 1 is a simple MCL program that when executed creates a simple modeless dialog window containing a counter value as a static text item, and two push buttons. When pushed, one of the buttons increments the counter and the other decrements the counter. The full source code to accomplish this is as follows:

Listing 1. MCL Counter Code Example

Counter
;;
;; define a global variable to hold the count value
;;
(defvar *value* 0)

;;
;; incr-item function called when Increment is clicked
;;
(defun incr-item (item)
  (if (<= *value* 999)
    (setq *value* (1+ *value*)))
  (set-dialog-item-text item (format nil "~3,'0D" *value*)))

;;
;; decr-item function called when Decrement is clicked
;;
(defun decr-item (item)
  (if (> *value* 0)
    (setq *value* (1- *value*)))
  (set-dialog-item-text item (format nil "~3,'0D" *value*)))

;;
;; create the dialog window and all of its subviews
;;
(make-instance 'dialog
  :window-title "Increment & Decrement"
  :view-size #@(230 100)
  :view-subviews
  (list
     (make-instance 'static-text-dialog-item
       :view-position #@(75 10)
       :dialog-item-text "Value:")
     (make-instance 'static-text-dialog-item
       :view-position #@(120 10)
       :dialog-item-text "000"
       :view-nick-name 'value)
     (make-instance 'button-dialog-item
       :view-position #@(30 50)
       :dialog-item-text "Increment"
       :dialog-item-action
       #'(lambda (item)
             (incr-item (find-named-sibling item 'value))))
      (make-instance 'button-dialog-item
       :view-position #@(120 50)
       :dialog-item-text "Decrement"
       :dialog-item-action
       #'(lambda (item)
             (decr-item (find-named-sibling item 'value))))))

The code in listing 1 is fairly self-explanatory. The first two function definitions implement the actions necessary to increment and decrement the counter. In this case, I have chosen to ensure that the counter value is always greater than or equal to zero. It is not allowed to become negative. This is an arbitrary decision - it could easily have been allowed to become negative and the tests would not be necessary in that case. When executed, the counter example appears as shown in Figure 1, with the Decrement button being pushed. The format function in the incr-item and decr-item functions causes the counter value to be displayed with leading zeros and with three digits.

Figure 1. MCL Counter Example During Execution

New Features and a Face Lift

When MCL is first placed into execution it opens a single “Listener” window into which you can type statements that are to be compiled and executed immediately. An example of the appearance of the Listener window after the Counter example was executed is shown in Figure 2. The question mark is MCL’s standard prompt for input. The code for the Counter example was stored in a file and was loaded and executed by choosing the Load File command from the File menu.

Figure 2. Listener Window Appearance

The new version of MCL includes a number of new features and a major face-lift for many of its “tool” dialogs (many of which were quite ugly in the previous version). The Apropos tool window, which is used to find functions, variables, classes, or macros is shown in Figure 3. Both the appearance and functionality of this tool is greatly enhanced in the new version.

Figure 3. Apropos Tool Window

The Apropos window shown in Figure 3 also shows the results of searching for references to window-related functions. The WINDOW-CLOSE function is highlighted in the list, indicating that it has been chosen by clicking on the entry. At this point, the function can be inspected, callers of the function can be listed, or documentation for the function can be retrieved. If source code exists for the function, then that also can be shown and its methods can be listed.

In addition to the Apropos tool, there is also a new Trace tool window. This tool is convenient for tracing the execution of a number of functions when a program is being debugged. An example of the appearance of this window and also the Listener window is shown in Figure 4.

Figure 4. Trace and Listener Windows

Figure 4 shows the results of tracing a single execution of the incr-item function. The Trace window shows that the incr-item function is to be traced and that its name and arguments are to be printed (in the Listener window) upon entry, and that its value (result) is to be printed when it exits. The results of the trace action are displayed in the Listener window, which is also shown in the figure. Any number of functions can be traced. The actions upon entry to a function can be to print its name and arguments, break (i.e., halt execution and prompt the user to perform some action at the Listener prompt), or perform no action. The actions upon exit from a function can be to print its name and values (result), break to allow the user to perform some action, or do nothing.

Actions at a break can include choosing to display the values of variables, modifying the source code, or any other related action. Other debugging aids, such as stepping the execution of a function, expression by expression, can be invoked by typing commands into the Listener window. Execution can be easily resumed at a break by typing Command-/ into the Listener window.

In addition to the tools just mentioned, MCL also includes an Inspector window. This is used to inspect the internal features of any MCL object or variable. You can either enter the name of the item to be inspected into the Apropos tool window, choose the type of the item from the pop-up menu, and then click the Inspect button; or you can simply type (inspect item ) into the Listener and an Inspector window showing the appropriate features of the item will be displayed. Figure 5 shows the contents of the Inspector window when the variable *value* (from the Counter example) is being inspected.

Figure 5. Inspector Window

Figure 5 shows the contents of the *value* variable when (inspect *value*) is typed into the Listener. Notice that the value is shown in many different forms, any of which might be of interest to you as the user. Other variations of the appearance of the Inspector window are common when different types of MCL objects are being inspected.

MCL 3.0 also provides the ability to change quite a number of preferences. This is accomplished in a new Preferences window. This window is shown in Figure 6.

Figure 6. Preferences Window

The Preferences window shown in Figure 6 includes a pop-up menu at its top that allows Environment (shown), Compiler, and also Printing preferences to be viewed and changed. Each of the preference items is a global variable (commonly written with leading and trailing asterisk characters to identify it as such). Each of the variables takes on a true or false value. The Documentation pane at the bottom of the window describes the selected preference variable’s function.

Interface Development Toolkit

MCL 3.0, like the previous version, offers a somewhat lame Interface Development Toolkit. This feature allows the development of simple application interfaces that consist of windows or dialogs containing buttons, text fields, and menus. It is clearly a limited facility and is one of the areas where MCL could definitely be improved. While the tool is relatively easy to use and offers a point and click approach to interface design, the number and type of interface elements is very limited. Once an interface is designed, however, you can automatically generate the code to recreate the interface. In that respect, it’s at least a help.

Processes & Process Scheduling

Version 3.0 of MCL includes the ability to create and schedule multiple processes. This feature facilitates the concurrent execution of computational tasks. When MCL starts up it creates two processes. The first, called “Initial,” is responsible for processing events. The second, called ”Listener,” is responsible for accepting input from the user in the Listener window (i.e., it runs the read-eval-print loop). Processes can have assigned priorities and processes with the same priority run in a round-robin fashion. Regardless of the priority assigned to a process, it will not run any longer than the time interval specified when the process was created. The status of all existing processes can be displayed by opening the Process window from the Tools menu. The appearance of the Process window is shown in Figure 7.

Figure 7. Process Window

Figure 7 shows that only the Listener and Initial processes currently exist. If the user’s program had created other processes, thier names and their statistics would have appeared in the Process window as well.

Locks are provided to enable multiple processes to be synchronized. A lock is like a semaphore. When one process obtains a lock, any other process attempting to obtain that lock will block until the lock has been released by the original owner. Processes can also be placed into queues, where they execute in the order in which they were entered into the queue. These are major new features in MCL 3.0.

Saving an Application

MCL 3.0 has a new tool that makes the task of saving an application much easier than the previous save-application function call. The appearance of the Save Application tool’s window is shown in Figure 8.

Figure 8. Save Application Tool Window

The Application class, Menubar, and Error handler choices are selected from pop-up menus in the Save Application window. Values can be typed into the other corresponding fields. There is provision for the contents of a resource file to be copied into the application. The Disable compiler checkbox ensures that the application will not be able to be used for development purposes.

Digitool will also offer a “Redistribution Kit,” for an extra charge. It should be available by the time you read this. The kit will offer the ability to truly excise the compiler from the saved application and reduce the size of the executable file significantly. I have no information about the kit, its cost, or any redistribution licensing costs at this time. You should check with either APDA or Digitool for this information.

A Few Problems Have Surfaced

Although the new MCL 3.0 product appears very stable, a few users have complained of problems when using it. Apparently there is some sort of incompatibility with WorldScript II and Kanji Talk, although Digitool is unable to confirm this. Also, a couple of people have reported problems when running the new product with accelerator boards. There don’t seem to be any serious problems with standard Mac computers (either 68K or PowerMac), except for the possible conflict with WorldScript.

The Bottom Line

I found MCL version 3.0 to be a great improvement over the previous version (2.0.1). However, there are areas in which it could be improved. The Interface Toolkit really needs to be developed into a much more comprehensive tool. In addition, the existing debugging aids, while helpful, are not very friendly and lack the ease of use that other modern development environments provide.

All in all, the MCL 3.0 product is a very worthwhile addition to your arsenal of tools. Its prototyping abilities are unexcelled and the overall breadth of the product is unequaled in any other environment.

In addition to the product itself, MCL 3.0 comes with over 200 megabytes of example code. It comes with the complete “Apple Programmer’s Toolbox Assistant” Quickview application and database on the product’s CDROM.

The product is available only on CDROM; however, Digitool has placed disk images for the product onto the CDROM disc, so if you don’t own a CDROM drive and have a friend who has one, you can copy the disk images and then install the product from floppy disks. However, you’ll also be missing access to the over 200 megabytes of contributed code, so if you’ve ever wanted an excuse to buy a CDROM drive, this could be it.

The Redistribution Kit is $400 regular price, or $350 educational price. The MCL complier may also be licensed, as a scripting language in an application for example, for $2000, or $1600 eudcational. MCL is $295, $135 for students. Digitool, Inc. One Main Street, Cambridge, MA 02142, (617)441-5000.

email: info@digitool.com

web: http://www.digitool.com

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Hazel 5.3 - Create rules for organizing...
Hazel is your personal housekeeper, organizing and cleaning folders based on rules you define. Hazel can also manage your trash and uninstall your applications. Organize your files using a familiar... Read more
Duet 3.15.0.0 - Use your iPad as an exte...
Duet is the first app that allows you to use your iDevice as an extra display for your Mac using the Lightning or 30-pin cable. Note: This app requires a iOS companion app. Release notes were... Read more
DiskCatalogMaker 9.0.3 - Catalog your di...
DiskCatalogMaker is a simple disk management tool which catalogs disks. Simple, light-weight, and fast Finder-like intuitive look and feel Super-fast search algorithm Can compress catalog data for... Read more
Maintenance 3.1.2 - System maintenance u...
Maintenance is a system maintenance and cleaning utility. It allows you to run miscellaneous tasks of system maintenance: Check the the structure of the disk Repair permissions Run periodic scripts... Read more
Final Cut Pro 10.7 - Professional video...
Redesigned from the ground up, Final Cut Pro combines revolutionary video editing with a powerful media organization and incredible performance to let you create at the speed of thought.... Read more
Pro Video Formats 2.3 - Updates for prof...
The Pro Video Formats package provides support for the following codecs that are used in professional video workflows: Apple ProRes RAW and ProRes RAW HQ Apple Intermediate Codec Avid DNxHD® / Avid... Read more
Apple Safari 17.1.2 - Apple's Web b...
Apple Safari is Apple's web browser that comes bundled with the most recent macOS. Safari is faster and more energy efficient than other browsers, so sites are more responsive and your notebook... Read more
LaunchBar 6.18.5 - Powerful file/URL/ema...
LaunchBar is an award-winning productivity utility that offers an amazingly intuitive and efficient way to search and access any kind of information stored on your computer or on the Web. It provides... Read more
Affinity Designer 2.3.0 - Vector graphic...
Affinity Designer is an incredibly accurate vector illustrator that feels fast and at home in the hands of creative professionals. It intuitively combines rock solid and crisp vector art with... Read more
Affinity Photo 2.3.0 - Digital editing f...
Affinity Photo - redefines the boundaries for professional photo editing software for the Mac. With a meticulous focus on workflow it offers sophisticated tools for enhancing, editing and retouching... Read more

Latest Forum Discussions

See All

New ‘Zenless Zone Zero’ Trailer Showcase...
I missed this late last week, but HoYoverse released another playable character trailer for the upcoming urban fantasy action RPG Zenless Zone Zero. We’ve had a few trailers so far for playable characters, but the newest one focuses on Nicole... | Read more »
Get your heart pounding quicker as Autom...
When it comes to mobile battle royales, it wouldn’t be disrespectful to say the first ones to pop to mind would be PUBG Mobile, but there is one that perhaps doesn’t get the worldwide recognition it should and that's Garena’s Free Fire. Now,... | Read more »
‘Disney Dreamlight Valley Arcade Edition...
Disney Dreamlight Valley Arcade Edition () launches beginning Tuesday worldwide on Apple Arcade bringing a new version of the game without any passes or microtransactions. While that itself is a huge bonus for Apple Arcade, the fact that Disney... | Read more »
Adventure Game ‘Urban Legend Hunters 2:...
Over the weekend, publisher Playism announced a localization of the Toii Games-developed adventure game Urban Legend Hunters 2: Double for iOS, Android, and Steam. Urban Legend Hunters 2: Double is available on mobile already without English and... | Read more »
‘Stardew Valley’ Creator Has Made a Ton...
Stardew Valley ($4.99) game creator Eric Barone (ConcernedApe) has been posting about the upcoming major Stardew Valley 1.6 update on Twitter with reveals for new features, content, and more. Over the weekend, Eric Tweeted that a ton of progress... | Read more »
Pour One Out for Black Friday – The Touc...
After taking Thanksgiving week off we’re back with another action-packed episode of The TouchArcade Show! Well, maybe not quite action-packed, but certainly discussion-packed! The topics might sound familiar to you: The new Steam Deck OLED, the... | Read more »
TouchArcade Game of the Week: ‘Hitman: B...
Nowadays, with where I’m at in my life with a family and plenty of responsibilities outside of gaming, I kind of appreciate the smaller-scale mobile games a bit more since more of my “serious" gaming is now done on a Steam Deck or Nintendo Switch.... | Read more »
SwitchArcade Round-Up: ‘Batman: Arkham T...
Hello gentle readers, and welcome to the SwitchArcade Round-Up for December 1st, 2023. We’ve got a lot of big games hitting today, new DLC For Samba de Amigo, and this is probably going to be the last day this year with so many heavy hitters. I... | Read more »
Steam Deck Weekly: Tales of Arise Beyond...
Last week, there was a ton of Steam Deck coverage over here focused on the Steam Deck OLED. | Read more »
World of Tanks Blitz adds celebrity amba...
Wargaming is celebrating the season within World of Tanks Blitz with a new celebrity ambassador joining this year's Holiday Ops. In particular, British footballer and movie star Vinnie Jones will be brightening up the game with plenty of themed in-... | Read more »

Price Scanner via MacPrices.net

Apple M1-powered iPad Airs are back on Holida...
Amazon has 10.9″ M1 WiFi iPad Airs back on Holiday sale for $100 off Apple’s MSRP, with prices starting at $499. Each includes free shipping. Their prices are the lowest available among the Apple... Read more
Sunday Sale: Apple 14-inch M3 MacBook Pro on...
B&H Photo has new 14″ M3 MacBook Pros, in Space Gray, on Holiday sale for $150 off MSRP, only $1449. B&H offers free 1-2 day delivery to most US addresses: – 14″ 8-Core M3 MacBook Pro (8GB... Read more
Blue 10th-generation Apple iPad on Holiday sa...
Amazon has Apple’s 10th-generation WiFi iPad (in Blue) on Holiday sale for $349 including free shipping. Their discount applies to WiFi models only and includes a $50 instant discount + $50 clippable... Read more
All Apple Pencils are on Holiday sale for $79...
Amazon has all Apple Pencils on Holiday sale this weekend for $79, ranging up to 39% off MSRP for some models. Shipping is free: – Apple Pencil 1: $79 $20 off MSRP (20%) – Apple Pencil 2: $79 $50 off... Read more
Deal Alert! Apple Smart Folio Keyboard for iP...
Apple iPad Smart Keyboard Folio prices are on Holiday sale for only $79 at Amazon, or 50% off MSRP: – iPad Smart Folio Keyboard for iPad (7th-9th gen)/iPad Air (3rd gen): $79 $79 (50%) off MSRP This... Read more
Apple Watch Series 9 models are now on Holida...
Walmart has Apple Watch Series 9 models now on Holiday sale for $70 off MSRP on their online store. Sale prices available for online orders only, in-store prices may vary. Order online, and choose... Read more
Holiday sale this weekend at Xfinity Mobile:...
Switch to Xfinity Mobile (Mobile Virtual Network Operator..using Verizon’s network) and save $500 instantly on any iPhone 15, 14, or 13 and up to $800 off with eligible trade-in. The total is applied... Read more
13-inch M2 MacBook Airs with 512GB of storage...
Best Buy has the 13″ M2 MacBook Air with 512GB of storage on Holiday sale this weekend for $220 off MSRP on their online store. Sale price is $1179. Price valid for online orders only, in-store price... Read more
B&H Photo has Apple’s 14-inch M3/M3 Pro/M...
B&H Photo has new Gray and Black 14″ M3, M3 Pro, and M3 Max MacBook Pros on Holiday sale this weekend for $100-$200 off MSRP, starting at only $1499. B&H offers free 1-2 day delivery to most... Read more
15-inch M2 MacBook Airs are $200 off MSRP on...
Best Buy has Apple 15″ MacBook Airs with M2 CPUs in stock and on Holiday sale for $200 off MSRP on their online store. Their prices are among the lowest currently available for new 15″ M2 MacBook... Read more

Jobs Board

Omnichannel Associate - *Apple* Blossom Mal...
Omnichannel Associate - Apple Blossom Mall Location:Winchester, VA, United States (https://jobs.jcp.com/jobs/location/191170/winchester-va-united-states) - Apple Read more
Senior Product Manager - *Apple* - DISH Net...
…Responsibilities** We are seeking an ambitious, data-driven thinker to assist the Apple Product Development team as our Wireless Product division continues to grow Read more
Senior Product Manager - *Apple* - DISH Net...
…Responsibilities** We are seeking an ambitious, data-driven thinker to assist the Apple Product Development team as our Wireless Product division continues to grow Read more
Senior Software Engineer - *Apple* Fundamen...
…center of Microsoft's efforts to empower our users to do more. The Apple Fundamentals team focused on defining and improving the end-to-end developer experience in Read more
Omnichannel Associate - *Apple* Blossom Mal...
Omnichannel Associate - Apple Blossom Mall Location:Winchester, VA, United States (https://jobs.jcp.com/jobs/location/191170/winchester-va-united-states) - Apple Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.