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

FontExplorer X Pro 5.0.1 - Font manageme...
FontExplorer X Pro is optimized for professional use; it's the solution that gives you the power you need to manage all your fonts. Now you can more easily manage, activate and organize your... Read more
Calcbot 1.0.2 - Intelligent calculator a...
Calcbot is an intelligent calculator and unit converter for the rest of us. Featuring an easy-to-read history tape, expression view, intuitive conversion, and much more! Features History Tape -... Read more
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

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.