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

Thunderbird 52.2.0 - Email client from M...
As of July 2012, Thunderbird has transitioned to a new governance model, with new features being developed by the broader free software and open source community, and security fixes and improvements... Read more
Airfoil 5.6.1 - Send audio from any app...
Airfoil allows you to send any audio to AirPort Express units, Apple TVs, and even other Macs and PCs, all in sync! It's your audio - everywhere. With Airfoil you can take audio from any... Read more
Apple Remote Desktop Client 3.9.3 - Clie...
Apple Remote Desktop Client is the best way to manage the Mac computers on your network. Distribute software, provide real-time online help to end users, create detailed software and hardware reports... Read more
jAlbum Pro 14.0 - Organize your digital...
jAlbum Pro has all the features you love in jAlbum, but comes with a commercial license. You can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly... Read more
jAlbum 14.0 - Create custom photo galler...
With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly, with pro results - Simply drag and drop photos into groups, choose a design... Read more
Vitamin-R 2.48 - Personal productivity t...
Vitamin-R creates the optimal conditions for your brain to work at its best by structuring your work into short bursts of distraction-free, highly focused activity alternating with opportunities for... Read more
Beamer 3.3 - Stream any movie file from...
Beamer streams to your Apple TV.... Plays any movie file - Just like the popular desktop movie players, Beamer accepts all common formats, codecs and resolutions. AVI, MKV, MOV, MP4, WMV, FLV. To... Read more
Shredo 1.2.2 - $9.99
Shredo is a beautiful, functional file-shredding and privacy scan utility. It permanently shreds files, folders, and external volumes' contents to keep information secure and impossible for anyone to... Read more
Final Draft 10.0.3 - Industry-leading sc...
Final Draft allows you to use your creative energy to focus on the content; let Final Draft take care of the style. Final Draft is the number-one selling application specifically designed for writing... Read more
Google Chrome 59.0.3071.109 - Modern and...
Google Chrome is a Web browser by Google, created to be a modern platform for Web pages and applications. It utilizes very fast loading of Web pages and has a V8 engine, which is a custom built... Read more

Latest Forum Discussions

See All

Solve the disappearance of history’s gre...
Blue Brain Games invites you to indulge in an immersive hands-on 3D puzzle adventure in similar vein to The Room series, with its debut release The House of Da Vinci. Set during the historic period of the Italian Renaissance (when Leonardo himself... | Read more »
Age of Rivals (Games)
Age of Rivals 3.3 Device: iOS Universal Category: Games Price: $.99, Version: 3.3 (iTunes) Description: Deep civilization-building strategy in a fast-paced card game! | Read more »
Panthera Frontier (Games)
Panthera Frontier 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: | Read more »
Angry Birds Evolution beginner's gu...
Angry Birds changes things up a fair bit in its latest iteration, Angry Birds Evolution. The familiar sling-shot physics mechanics are still there, but the game now features team-based gameplay, RPG elements, and a new top-down view. With all of... | Read more »
Sega Forever is for the retro game fans
Sega is launching a new retro games service titled Sega Forever, in a move that's sure to delight games enthusiasts with a bit of nostalgia. Sega's releasing five classic games for free. The titles include Sonic the Hedgehog, Phantasy Star II,... | Read more »
The Little Acre (Games)
The Little Acre 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: | Read more »
Lovely adventure game 'The Little A...
The Little Acre makes its way from PC to iOS today and it's a real charmer. It's a lovely little adventure game set in 1950's Ireland, gorgeously animated in a style slightly reminiscent of old Disney films. The game won a lot of praise for its... | Read more »
Futurama: Worlds of Tomorrow officially...
Futurama: Worlds of Tomorrow arrives next Thursday, and it features . . . Stephen Hawking? Turns out a few of your favorite science super stars, including Bill Nye, Neil DeGrasse Tyson, and George Takei will be making an appearance alongside the... | Read more »
MU Origin’s new update offers exciting c...
MU Origin is kicking off the summer with style. Its latest update is a real doozy, offering up plenty of fresh content. New challenges, some extra help for newcomers, and new costumes are just a few of the things you will find in the new patch. | Read more »
Pokémon GO introduces Raid Battles and a...
If you were hoping to conquer any gyms today in Pokémon GO you're in for a bit of disappointment. Niantic has closed gyms in the game to prepare for a huge upcoming update that is going to complete change Pokémon GO's competitive elements. The... | Read more »

Price Scanner via MacPrices.net

Clearance 2016 MacBook Pros available for up...
B&H Photo has clearance 2016 13″ and 15″ MacBook Pros in stock today and on sale for up to $400 off original MSRP. Shipping is free, and B&H charges NY & NJ sales tax only: - 15″ 2.7GHz... Read more
Apple Ranks 9th In comScore Top 50 U.S. Digit...
comScore, Inc. has released its monthly ranking of U.S. online activity at the top digital media properties for May 2017 based on data from comScore Media Metrix Multi-Platform. * Entity has... Read more
10.5-inch iPad Pros available for up to $20 o...
B&H Photo has the new 2017 10.5″ iPad Pros available for up to $20 off MSRP including free shipping plus NY & NJ sales tax only: - 64GB iPad Pro WiFi: $649 - 256GB iPad Pro WiFi: $749 - 512GB... Read more
Three Off-The-Beaten-Track iOS Apps That Dese...
One of the great things about using iPads and iPhones is the vast selection of apps available for most anything you want or need to do. The three outlined in this article have been in my core app... Read more
Apple No. 1 Spot In Gartner Top 100 Vendors i...
Gartner, Inc. has unveiled the top global 100 vendors in IT in 2016 based on their revenue across IT (excluding communication services) and component market segments. In the Gartner Global Top 100:... Read more
Clearance iMacs available for up to $300 off...
B&H Photo has clearance 21″ and 27″ Apple iMacs available starting at $949, each including free shipping plus NY & NJ sales tax only: - 27″ 3.3GHz iMac 5K: $1999 $300 off original MSRP - 27″... Read more
1.4GHz Mac mini, refurbished, available for $...
The Apple Store has Apple Certified Refurbished 1.4GHz Mac minis available for $419. Apple’s one-year warranty is included, and shipping is free. Their price is $80 off MSRP, and it’s the lowest... Read more
Free Mixoo iOS Photo Editing App Gets Major U...
Button Software Technology has announced Mixoo 3.0, an important feature update to the company’s photo editor for iOS devices. Mixoo offers amazing ways to edit as well as decorate personal photo... Read more
FNable 2.0 Function Key Enabling Software Get...
Briksoftware has released FNable 2.0 With Touch Bar Support, a major new version of the function key enabling software now compatible with Touch Bar keyboards. FNable’s simplicity that allows users... Read more
Clearance 2016 12-inch Retina MacBooks, Apple...
Apple recently dropped prices on Certified Refurbished 2016 12″ Retina MacBooks, with models now available starting at $1019. Apple will include a standard one-year warranty with each MacBook, and... Read more

Jobs Board

Product Manager, *Apple* News - Apple Inc....
…on new product areas, many of which have great potential impact to Apple .Drives the definition of broad, complex, and high impact products for worldwide markets, Read more
Sr. Software Engineer, *Apple* Online Store...
…building high throughput, high performance, reliable, checkout & payment platform that support Apple online stores. You will be working with the latest in services Read more
Product Owner, *Apple* Communities - Apple...
…for managing and delivering a world-class community experience to Apple 's customers. Your primary responsibilities include developing internal-facing tools, Read more
*Apple* Customer Experience (ACE) Leader - A...
…management to deliver on business objectivesTraining partner store staff on Apple products, services, and merchandising guidelinesCoaching partner store staff on Read more
Pan Europe Market Development Manager %u2014...
…local artists across the region.* Building strong relationships with local Apple teams & collaborating on mutually beneficial projects.* Building strong Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.