AppleScript 1.4.0 and 1.4.3 (Mac OS 9 and 9.0.4)

AppleScript 1.4.0 is included with Mac OS 9.0 (code name Sonata), announced by Steve Jobs at a special Apple Event on October 5, 1999 for release on October 23, 1999. It follows AppleScript 1.3.7, which was released in April 1999 with Mac OS 8.6.

AppleScript 1.4.3 was announced as a minor bug fix, in conjunction with the release of the Mac OS 9.0.4 updater, on April 4, 2000, but the new extension was to be made available somewhat later. The AppleScript 1.4.3 updater was finally posted on May 18, 2000, and the English-International edition on July 19, 2000. Chris Espinosa, Manager, Components & Scripting, at Apple announced on August 6, 2000 that a corrupt copy of AppleScript 1.4.3Z, the English-International edition, was inadvertently posted on the Apple software updates sites from mid-May to early July. A symptom, if you have the corrupted file, is that compiled scripts appear to have no text when they are reloaded. If you have experienced this problem, you are urged to re-download the now corrected AppleScript 1.4.3Z. (A few days later, Mark Alldritt posted Script Rescue, a utility that recovers scripts lost due to the corrupt version of AppleScript 1.4.3Z.) 8/14/00

Like the notes on AppleScript 1.3.7, AppleScript 1.3.4and AppleScript 1.1.2, this note is based on information obtained from various sources, including official Apple publications and the AppleScript mailing lists.

NEW FEATURES IN APPLESCRIPT 1.4.0 and 1.4.3

AppleScript 1.4.0 contains both bug fixes and a fairly significant number of new features. These new features are notable:

The Users & Groups control panel is now part of the File Sharing control panel. Existing scripts targeted at the former must be rewritten to target the latter.

The Memory control panel is now scriptable, allowing you to get and set virtual memory, RAM disk and disk cache settings and to get information about available disks (including whether a disk is the startup disk and which disk holds the virtual memory storage file). You can also determine whether a memory configuration is currently active or will take effect after restart. 10/17/99

The Mouse control panel is now scriptable. For example, your scripts can set the ‘mouse tracks’ setting and turn on the ‘thick ibeam’ cursor. 10/17/99

The new FontSync Extension system extension and FontSync control panel application are scriptable, allowing scripters to match font characteristics between computers and get and set font matching options. FontSync comes in the Font Extras folder of the Apple Extras folder and can be used there, but it can optionally be placed in the Control Panels folder if used frequently. FontSync is used to set font-matching options. The FontSync Extension is used to do the actual work of creating profiles and performing comparisons using the FontSync matching options that are currently in force. The extension is another in the series of system components whose only user interface is AppleScript, so the field is open for FaceSpan developers and others to create an onscreen user interface. Scripts are included to create a FontSync profile of the fonts installed on your computer and to compare that profile with the fonts installed on another computer (say, a computer at a printing service). Preliminary developer technical documentation includes detailed information on how to script FontSync. 11/7/99

‘Tell’ blocks can now accept URLs in the ‘machine’ parameter, allowing AppleScript control of remote applications via TCP/IP (i.e., over networks and the Internet). Scripts using this feature will not work under earlier versions of AppleScript or the Mac OS. The dialog box opened by the ‘choose application’ command in the Standard Additions scripting addition now includes a checkbox to enable the user to choose applications over IP protocols, although the AppleScript command itself has not changed. A new ‘choose URL’ command in Standard Additions is implemented to let the user choose a network service and return its URL. Detailed explanations and sample scripts are available in the Program Linking over IP AppleScript GuideBook module. In addition, an article was published in November 1999 in TidBITS #504 offering an overview of technical issues and techniques. 11/7/99

A new Keychain Scripting application is included in the Scripting Additions folder. With appropriate Keychain settings, background-only applications can send Apple events to processes on remote machines requiring authentication, without user interaction.

The Apple Verifier application implements AppleScript commands to verify and open files as part of the new security facilities of Mac OS 9. 10/17/99

A new ‘using terms from’ construct allows ‘tell’ blocks to use the terminology dictionary of a specific application at compile time, replacing the double-tell technique described in the Mac OS 8.6 Technote. Scripts using this construct will not work under earlier versions of AppleScript or the Mac OS. The ostensible purpose for this new construct is to allow compilation of scripts using a local application’s dictionary while targeting the same application on a remote machine which is not online at compile time. It apparently also can replace the double-tell technique more generally. Other changes were also made to reduce the incidence of requests to a script’s user to locate a targeted application. For example, the system now automatically locates scriptable system components in the Scripting Additions folder, the Control Panels folder and the Extensions folder with the given name. Specifying the target of a ‘tell’ statement by using a full path name will fail with an error if the application does not exist in that location, instead of asking the user to locate it.

A ‘busy status’ property has been added to the ‘file information’ class returned by the ‘info for’ command in the Standard Additions osax, allowing a script to repeatedly test whether a file is busy before performing some action on it. 10/17/99

The ‘on error’ section of a ‘try’ block is now optional.

AppleScript now loads at component registration time, not INIT time. Nevertheless, a gestalt selector is set at boot time so that INITs requiring AppleScript will function properly.

Errors from Navigation Services are now reported. When using ‘choose file’, ‘choose folder’, ‘new file’, ‘store script’ or similar commands, scripts should perform appropriate error checking. Also, partial path names are now supported.

These new ‘path to’ constants are added: ‘keychain folder’, ‘users folder’, ‘current user folder’ and ‘system preferences’.

There are changes to folder actions. For example, certain Finder errors are now reported explicitly. Also, the folder action server stops processing all Apple events and scripts upon receipt of a ‘quit’ message in order to facilitate the new multiuser capabilities of Mac OS 9.

The Dialects folder is no longer required, and the English dialect is now incorporated within the AppleScript extension.

Application support for scriptable printing allows developers to create applications in which scripts can set printing options. Applications require modest changes to implement support for a new, optional ‘print settings’ class. Some features require driver support. Laserwriter 8.7 contains this support.

PlainTalk 2.0, an optional installation, is markedly improved. For scripters, a new scriptable Speech Listener Application allows scripts to specify a list of phrases to listen for, to speak an optional prompt and to give up after listening for a specified time, enabling us to create robust interactive voice-controlled scripts. The ‘listen for’ event returns the recognized phrase, if any. I anticipate a deluge of corny scripts. The SpeakableItems system extension is also now scriptable. With it, you can turn on active listening (i.e., making it unnecessary to push a key), and you can show the user a window listing available commands, (optionally for the frontmost application only). Many speakable items have been updated for use with new Mac OS 9 features, including to speak the names of common buttons in most applications. Speakable items can now be restricted to the frontmost application, if desired, using an Application Speakable Items folder with application subfolders, on the model of OSA Menu. This has the effect of improving speech recognition sensitivity, because it reduces the total number of phrases being listened for. Speakable items for the Finder, Internet Explorer, Netscape Communicator and Outlook Express are supplied upon installation of the Mac OS. 10/17/99

Script Editor has undergone a few changes and is now versioned at 1.4.1, but it is still very basic. It is now carbonized so that it will run in Mac OS X. An option has been added to save applets with a carbonized shell so that they will run under Mac OS X (and also under earier versions of the Mac OS, back to Mac OS 8.1, which have CarbonLib installed). The default setting for applets has been changed to Never show startup screen. The left pane of the dictionary window now widens proportionately when the window is enlarged.

QuickTime Player, part of QuickTime 4, implements AppleScript commands to play a movie from an URL. 10/17/99

The Browse the Internet and Mail applications are actually AppleScript applets. According to their descriptions, they call commands in the Internet Scripting scripting addition. However, this scripting addition, which is part of Apple Data Detectors, is not installed by Mac OS 9; I believe it is only a terminology resource for writing scripts and that it provides no executable code. Both applets work properly without the Internet Scripting addition, although the Apple events in the scripts appear in raw event format if you examine them in the Script Editor. I don’t know where their executable code resides. 10/29/99

New features have been added to the API for developers (for example, to flush the terminology cache). However, they are reportedly not working correctly.

Many AppleScripts buried in Mac OS 9 (especially in the Apple Help folder) have been revised for Mac OS 9. In March 2000, SmartMac posted an article by Michael Locke entitled Hide and Seek AppleScript, which explains how to locate all these AppleScripts. 4/11/00

DOCUMENTATION FOR NEW APPLESCRIPT FEATURES

The following sources of information about AppleScript 1.4.0 and 1.4.3 are available.

It appears that the Help files for AppleScript used with the Apple Help Viewer were not updated on the CD to add information about what’s new in AppleScript 1.4. However, the official AppleScript site has been updated with a summary list of what’s new, and with new help documentation for AppleScript 1.4 taking the form of a new AppleScript GuideBook module for Program Linking over IP and an updated GuideBook module for the Beginner’s Tutorial. More of Sal Soghoian’s excellent GuideBook modules for Apple Help Viewer are promised shortly. 11/7/99

These readme documents are installed in a standard system install or available for optional installation on the Mac OS 9 CD:

The About AppleScript document in the AppleScript subfolder of the Apple Extras folder describes several of the new features of AppleScript 1.4, with a couple of examples.
All seven of the AppleScript Guidebook modules which have been available on the AppleScript web site for some time are installed in the AppleScript Extras folder. Although these have not been updated for new features in AppleScript 1.4, I strongly urge you to install each of them using the provided installers.
A Sample Scripts ReadMe document explaining the supplied ColorSync scripts is installed in the ColorSync folder. These relate to ColorSync 2.6, but they are still valid because there have been no significant changes in the ColorSync 3.0 dictionary.
An About AppleScript CD Extras document which explains the folder contents is installed in the AppleScript Extras folder.
A few other documents are included in some of the folders described in the Installed Components section, below. 10/29/99

Mac OS 9.0 (Technote 1176 10/5/99, , updated 3/27/00) discusses changes and corrections in the next generation of Mac OS: Mac OS 9, including detailed information about AppleScript 1.4 and scriptable components of the Mac OS. Revision 2 of the Technote reveals that, if you put an alias to an application in the Scripting Additions folder, your scripts will automatically use the alias to locate the application. The TN points out that you can use an abbreviation for the name of the alias (like FM for FileMaker Pro) and write your scripts to ‘tell app FM’, and you won’t get the infamous where is dialog. 4/11/00

LaserWriter 8.7: Scriptable Printing (Technote 1178 10/5/99) explains how developers can implement the new AppleScript facilities of Mac OS 9 relating to printing. This mainly deals with how application developers can incorporate custom control via AppleScript.

Extending and Controlling Sherlock (Technote 1141, updated 11/2/99) contains an extensive discussion of AppleScript support in Sherlock, including AppleScript changes for Sherlock 2 introduced with Mac OS 9 (adding the ‘in channel’ parameter to the ‘search Internet’ command). 11/7/99

Packages in Mac OS 9 (Technote 1188 10/13/99) describes the new package construct introduced in Mac OS 9. See also Mac OS 9: What’s New - Package Files (TIL #60502 9/30/99, updated 10/21/99). Packages will come to full fruition in Mac OS X. The Technote explains that a package is actually a folder with a bit set to tell the Finder to make it look and act like a file. Oversimplifying, it must contain at least an application file or a document file, and a relative alias at its top level pointing to that file. But it can also contain ancillary applications, libraries, help files, scripts and other files contained in the package or its subfolders, nested in any hierarchy. The objective is to enable developers to group within one structure all of an application’s support files, which are hidden from the user by the containing folder. Developers are urged to consider placing support files in the package instead of in the System Folder. What does this have to do with AppleScript? Interestingly, a package can be assembled by a script. One scripter has already done this: Anthony Pittari’s Parcel 1.0 is an AppleScript droplet that turns folders into packages and vice versa. It requires Mac OS 9 and the Akua Sweets and Jon’s Commands scripting additions. Interestingly, it isn’t really a droplet but is instead itself a package. Public Access Software has released Tape, and Andy Monitzer has posted MakePackage, two other utilities to create packages. Version 1.0b2 of Tape added scriptability. The popular and venerable File Typer has been updated to support conversion between folders and packages, too. 11/7/99

Technote 1190 about the system’s Power Manager points out that the Mac OS now broadcasts certain Apple events when your computer is about to run out of battery power or is about to go to sleep. These events are broadcast to all high-level-event aware applications. An AppleScript applet’s ‘SIZE’ resource has its high-level-event aware flag set, so an applet should be able to receive these broadcast events and detect imminent sleep due to low battery power or scheduled sleep. 12/24/99

Technote 1194, Mac OS Update 9.0.4, describes bug fixes introduced with the announcement of AppleScript 1.4.3. 4/11/00

TESTING WHETHER APPLESCRIPT 1.4.0 OR 1.4.3 IS INSTALLED

Before using new features of AppleScript, careful writers of scripts intended for public distribution will want to determine which version of AppleScript is present on the user’s machine. How to do this is explained in the article on AppleScript 1.3.4. The numbers to test for to determine whether AppleScript 1.3.7 or 1.4.0 is installed are these:

AS 1.3.7 = 17826103 (01100137)
AS 1.4.0 = 17826112 (01100140)
AS 1.4.3 = 17826115 (01100143)
4/11/00

APPLESCRIPT-RELATED SYSTEM SOFTWARE COMPONENTS

Installed Components
Several new scriptable components are installed in Mac OS 9, as described in the New Features section, above.

In addition, a standard Mac OS 9 installation places these AppleScript-related items in the Apple Extras folder on your hard disk:

In the AppleScript folder, the new Script Editor 1.4.1, a short About AppleScript document explaining some of the new features of AppleScript 1.4, and the AppleScript Guide file.
In the ColorSync folder, a subfolder of scripts and a Sample Scripts ReadMe document. The document is for ColorSync 2.6; there are no significant new scripting features in ColorSync 3.0.
In the Font Extras folder, the new scriptable FontSync control panel and two scripts required to make use of its settings. 10/29/99

The Mac OS 9 CD contains these optional items related to AppleScript, which are not installed automatically by the standard Mac OS 9 installation but can be dragged from the CD:

In the AppleScript Extras folder: a light version of the iDo Script Scheduler 1.0 control panel (a newer and more powerful version, iDo Script Scheduler 1.1, is available commercially from the developer); an installer for the light version of OSA Menu (a more capable version, OSA Menu 1.2, is available free from the developer); all seven of the AppleScript Guidebook modules which have been available on the AppleScript web site for some time, with installers to add them to Apple Help; and a folder with More Sample Scripts arranged for use by OSA Menu (in Finder, Script Editor, Folder Actions and Universal subfolders), ready to be dragged into the Scripts folder in your System Folder. The additional scripts have not been revised since Mac OS 8.6. It also includes an About AppleScript CD Extras document which explains the contents of the AppleScript Extras folder, including the additional scripts.
In a subfolder of the HyperCard Update folder, which provides the 1997 HyperCard 2.4.1 udpate, the old HyperCard AppleScript Reference stack last modified in 1997.
In the OTExtras subfolder of the Network Extras folder, a Sample AppleScripts folder showing proper syntax to script the Network Setup Scripting application (including a NSS skeleton stationery pad to make it easier to write your own).
In the Remote Access subfolder of the Network Extras folder, a Sample AppleScripts folder for Remote Access.
In the Palm Extras folder of the Palm Desktop folder, an AppleScripts folder with useful scripts. 10/29/99

Dictionary Changes
Several changes have been made to scriptable components of the Mac OS that have been updated from their Mac OS 8.6 versions. Most of the changes are minor, but more extensive changes have been made to the dictionaries for the File Sharing control panel application, the Remote Access Commands and Standard Additions scripting additions and the Apple System Profiler desk accessory application. 10/29/99

ColorSync Extension system extension
The version has increased to 3.0 from 2.6.1. The ‘saving into’ parameter is now ‘saving in’ in the ‘match’, ‘proof’ and ‘match link’ commands. I haven’t tested this, but I am confident that old scripts will continue to function without recompiling. The ‘get’ and ‘set’ commands have disappeared from the dictionary in accordance with the Mac OS 8.6 changes to the Standard Suite, but the commands are, of course, still available in AppleScript. 10/29/99

File Exchange control panel application
The version has increased to 3.0.3 from 3.0.1. The spelling of the ‘includes servers’ property of class ‘application’ has been corrected. In Mac OS 8.6, it was ‘includs servers’. I haven’t tested this, but I am confident that old scripts will continue to function without recompiling. 10/29/99

File Sharing control panel application
The version has increased to 9.0 from 8.0. It has been extensively revised, and the former Users & Groups control panel’s functionality and scripting dictionary have been incorporated into it. Old scripts using the Users & Groups dictionary must be revised to target File Sharing. The old Users & Groups suite has not changed. The File Sharing suite now includes new ‘close’, ‘delete’, ‘duplicate’ and ‘make’ commands. The dictionary indicates that the ‘disconnect’ command now takes a list of ‘connected user’ instead of a list of ‘anything’, and the ‘show privileges of’ command now takes a list of ‘shared item’ instead of a list of ‘anything’. Class ‘application’ now contains new ‘connected user’ and ‘shared item’ elements and the corresponding classes are provided. The ‘get’ and ‘set’ commands have disappeared in accordance with the Mac OS 8.6 changes to the Standard Suite, but the commands are, of course, still available in AppleScript. 10/29/99

Network Setup Scripting application in the Scripting Additions folder
The version has increased to 1.1.1 from 1.0.2. The dictionary now indicates that the ‘consequence’ property of the ‘transport options’ class in the Open Transport suite returns the constants ‘benign’, ‘may affect services’, ‘must restart configuration’, ‘must restart protocol’ and ‘must restart computer’, instead of the value ‘otgc’. There are also AppleTalk, Modem, Remote Access and TCP/IPv4 suites. 10/29/99

Remote Access Commands scripting addition
The version has increased to 3.5 from 3.1.3. Because Apple Remote Access 3.5 includes the personal server, the scripting dictionary has been enhanced with the addition of the ‘answer enabled’ and ‘is server’ properties of the ‘PPPStatusParam’ and ‘RAStatusParam’ classes. 10/29/99

Standard Additions scripting addition
The version has increased to 1.4 from 1.3.7. A new ‘choose URL’ command has been added to support the new ability of AppleScript to work over TCP/IP connections (for example, the Internet). Also, a new ‘busy status’ property has been added to the values returned in the ‘file information’ class by the ‘info for’ command, to let scripts determine whether a file is currently is use. In the Internet suite, the ‘schemes’ property of the ‘URL’ class returns several new constants, including ‘remote application URL’, ‘streaming multimedia URL’ and ‘network file system URL’. 10/29/99

URL Access Scripting application in the Scripting Additions folder
The version has increased to 2.0 from 1.0.1. The dictionary now indicates the default value of the several parameters to the ‘download’ and ‘upload’ commands. Apple’s AppleScript site was updated with a new AppleScript GuideBook help module for URL Access Scripting in January 2000. Apple published Technical Q&A NW 66 in April 2000, including information about undocumented error codes generated by the URL Access Manager which may be useful to AppleScripters using the URL Access scripting addition. 5/3/00

Apple System Profiler desktop accessory application
The version has increased to 2.4.2 from 2.2. The Apple System Profiler suite contains a great many additional classes, such as ‘System overview’ and ‘TCP information’, each with many properties allowing scripts to detect the presence of specific hardware and software features of the machine. The ‘Hardware overview’ class, for example, lets you determine the ‘LogicBoardNum’ in order to distinguish among various releases in a particular hardware model. The ‘ProductionOverview’ class even lets you determine the ‘SerialNumber’ of a specific machine (on my PowerBook G3 Series, it returns Not applicable; I guess Apple is planning for the future). The terminology style is not consistent with the prevailing AppleScript plain-English standard (many of the properties have no spaces between words but instead use embedded capitals to denote separate words), but the details made available to scripts is welcome. 10/29/99

Sherlock 2 application in the Apple Menu Items folder
The version has increased to 3.0.1 from 2.1, while the name has changed from Sherlock to Sherlock 2. Go figure. The ‘application’ class now contains a ‘channel’ element and a ‘current channel’ property, supported by a new ‘channel’ class reflecting the new channels feature of Sherlock 2. The ‘count’, ‘exists’, ‘get’ and ‘set’ commands have been added from the Standard suite. 10/29/99

Finder
The version has increased to 9.0 from 8.6. In the Standard suite, the ‘print’ command has a new, optional ‘with properties’ parameter. This is a record which may contain specific options supported by the drivers supplied with particular printers; see your printer’s documentation for details. This feature will become useful as more printer manufacturers or driver developers take advantage of the new scriptability features incorporated into the LaserWriter 8.7 file. The ‘application’, ‘container’, ‘sharable container’, ‘disk’, ‘folder’, ‘desktop-object’ and ‘trash-object’ classes contain a new ‘package’ element supported by a corresponding class. The ‘icon family’ class now includes the new ‘large 32 bit icon’ property, as well as new ‘large 8 bit mask’ and ‘small 8 bit mask’ properties. 10/29/99

The Scriptable Finder
Many long-standing bugs in the scriptable Finder, including some remaining from at least Mac OS 8.1, were not fixed in Mac OS 8.6. I listed what I regard as the eleven most important Finder bugs in the note on AppleScript 1.3.7 in Mac OS 8.6, along with three others. No fixes for Mac OS 9 are mentioned in Technote 1176.

Expanding on bug number 12 in my list, ‘move’ without designating a ‘to’ location not only moves the file to the desktop, but it doesn’t return a reference to its new location. The real bug, however, is that it is allowed to compile successfully, since the dictionary says the ‘to’ parameter is mandatory. 10/17/99

Preliminary testing indicates that the duplicate in place bug, number 2 in the list, has been fixed. The ‘duplicate’ command now returns a reference to the duplicated item even when it is a copy duplicated into the same folder as the original. None of the other bugs appears to have been addressed. 10/17/99

What was initially thought by many users to be a bug in the Finder’s icon positioning commands is now revealed, in Revision 2 of Technote 1176, to be a design change in the Finder’s behavior. The Mac OS 9 Finder does not allow icon positioning by way of AppleScript for icons appearing in icon views where either the ‘keep arranged’ or the ‘snap to grid’ option is turned on. If a script attempts to set the position of an icon in such a view, the Finder will return error code number -15274 (window wrong type). The error number will enable scripters to write error-trapping code into their scripts. Jon Pugh was the first to report this behavior, pointing out that one can work around it by turning off ‘keep arranged’ and ‘snap to grid’ before setting an icon’s position. 12/24/99

QuickTime 4.1
In January 2000, Apple released QuickTIme 4.1 and a very scriptable version of QuickTime Player. The release was accompanied by an extensive collection of AppleScript Scripts for QuickTime 4.1. The preliminary documentation for QuickTime 4.1, released shortly later, includes a chapter on AppleScript support in the Player. QuickTime 4.1: About AppleScript and QuickTime Player (TIL #60687 1/18/00, updated 1/20/00) describes the new scriptable QuickTime Player. Technote 1197, QuickTime 4.1.1/4.1.2, includes a note that QuickTime 4.1.1 fixed two AppleScript bugs in QuickTime Player: the frontmost window was not getting targeted by default, and the Close Every Window command would fail with an error. 5/23/00

FIXED BUGS
Only one AppleScript-related bug fix is mentioned in Technote 1176: a problem in the Process Manager that could cause slower Apple event performance in Mac OS 8.6 has been corrected.

However, there are many other AppleScript bug fixes, most of limited interest to scripters. For example, the behavior of the proxy icon in Script Editor now conforms to user interface standards. As noted above, the Finder’s duplicate in place bug has also been fixed. 10/17/99

One bug that was not fixed: The Desktop Printer Manager’s ‘SIZE’ resource is still set to Sizeand Min size of 131072, rather than 200000 as recommended in TIL article no. 31064, Mac OS 8.6: Out of Memory running an AppleScript. It is therefore possible that scripts using the Desktop Printer Manager will continue to fail with out-of-memory errors under Mac OS 9 unless users follow the instructions in the TIL article. 10/19/99

On November 5, 1999, Eric Hellman posted the results of his Mac OS 9 testing on the MacScripting mail list, quoted here:

I have learned that a number of other bugs were fixed in AppleScript 1.4:

Rounding errors in units were fixed
A crash in using identifier names that are exactly 252, 253, or 254 bytes long was fixed
Display dialog doesn’t display OSTypes any longer
typeMagnitude can be displayed using values greater than 4 gigabytes
Using the Run command with a system event (e.g., run beep) doesn’t loop infinitely now
Long application namess (over 63 characterss) on machine or zone names don’t crash now
Folder Actions now processes a quit event immediately, without waiting for a script to finish (this was done to prevent a trojan horse from running via the folder action script when multiple users is in use, which could happen when one user logged out and a new one logged in. 5/23/00

NEW BUGS IN MAC OS 9.0

The Mac OS 9.0.4 updater was released on April 4, 2000, this time for real after a couple of accidental appearances in the Software Update control panel a few days earlier. The section of new TechNote 1194, Mac OS Update 9.0.4, describing AppleScript-related changes for developers describes these three improvements over AppleScript 1.4 as released with Mac OS 9.0:

AppleScript 1.4.3 fixes a bug in AppleScript 1.4 that could cause a crash when compiling AppleScript simultaneously in two separate component connections.
Standard Additions 1.4.2 brings the Mount Volume command into sync with Mac OS 9 security features, so that volumes requiring secure logins (such as Mac OS X Server) can now be mounted.
Script Editor 1.4.3 fixes the Script Editor to eliminate substantial delays in Apple event processing when CarbonLib 1.0.2 is installed (Mac OS 9.0.4 does not install CarbonLib 1.0.2, but it is freely available). 4/11/00

I have learned that, contrary to reports, four (not three) problems have been fixed in the AppleScript 1.4.3 extension released belatedly on May 18, 2000, one apparently at the last minute: Mount Volume now works on non-AppleShare AFP servers (this bug was introduced by the Mac OS 9.0 change in the Appleshare Client to improve security); long delays with the Carbon Script Editor and early versions of CarbonLib were fixed (the Script Editor would hang for up to sixty seconds; be sure to run CarbonLib 1.0.2 or later); compiling scripts simultaneously resulted in a crash but does so no longer; and, not previously reported, a hang on Open Location was fixed. 5/23/00