TweetFollow Us on Twitter

September 96 - Newton Q & A: Ask the Llama

Newton Q & A: Ask the Llama


Q How can I open an application so that it displays a particular data item?

A If the target application supports Find, you can do that as long as three things are true:

  • You know the application symbol.

  • You know the application soup name and data format.

  • The application supports the ShowFoundItem message.
If all of these are true, you can send the application the ShowFoundItem message with the appropriate arguments. Check the Newton Programmer's Guide for the arguments to ShowFoundItem. Be aware that not every application takes a soup entry as one of the arguments. That's why you need to know the application's data format. You can check whether the application supports the ShowFoundItem message with the following code:
local theApp := GetRoot().(kAppSymbol);
if theApp AND theApp.ShowFoundItem exists then
   // application installed and supports the message
Q We have an application for a Newton device that communicates with the desktop. Because of the structure of our data, we'd like to be able to request a particular NewtonScript object. We thought of sending the reference or address of the NewtonScript object to the desktop and using that as the identifier, but we could find no way to do this. Are we missing something?

A Unfortunately (or fortunately, depending on your point of view), Newton 2.0 OS doesn't provide a way to get the memory address of an object. Actually, since NewtonScript can relocate objects at will, providing an address would not be a good idea. There's an alternate approach: you can maintain an array of the objects you want to export. The array index can be used in much the same way as the address. As an example, in the code below, the memory "address" for object2 would be 1. In other words, myObjectArray[1] would give you object2.

object1 := "foo";
object2 := {can: 'aid, eee: "an", a: "...yep"};
object3 := [1,2,3];
myObjectArray := [object1, object2, object3];
If you need to indicate that an object has already been transferred to the desktop, you can simply replace the object at the relevant array index with NIL.

Q I'm designing my data structures. I figure I could use either two cursors onto two different soups or two cursors onto the same soup. Which is the more efficient solution?

A You can measure efficiency in two relevant ways: by time or by memory usage (or both). The time to create the two cursors will be the same regardless of the number of soups, but more heap space will be required for two soups. With two soups, it may take less time to find items that exist in just one soup than when searching a larger, combined soup. However, with two soups you won't get as much benefit from the operating system's caching of the entries; there's more overhead information to swap in and out of the heap, which increases the time required to get data.

The real answer is to test it with your actual data and see. Overall, two cursors on one soup sounds like the more efficient way to go. Your question implies that you're going to have two completely different sets of data. You can do this in one soup by using indexes, because entries with either no indexed slot or NIL in an indexed slot won't participate in that index. That is, when you create a cursor that uses that index, entries with NIL values will be ignored by that cursor.

Something that might occur to you is using tags to implement the two different sets of data (that is, each set would have a unique tag value), but this doesn't work as well as using an index. With an index, you can navigate to an entry in O(log n) time, where n is the number of entries that are in that index. In other words, the time taken to navigate to a particular entry will be directly related to the log of the total number of entries. If your query includes a beginKey/endKey or startExclKey/endExclKey subrange, the system finds that subrange very quickly. It can then quickly step through entries in between.

The operating system gets the set of tags for an entry efficiently, but it has to know which entries to get the tags for first. So with no other way to narrow the search, it will check all the entries, assuming you aren't using an index. Getting the tags is actually very efficient, but indexes work better for subranging.

Q I'm trying to compile a program that works with both Newton 1.x and Newton 2.0 OS devices; however, it won't compile. Newton Toolkit complains that I have a bad magic pointer, but I know that the value is defined in the MessagePad platform file. The offending code is as follows:

local theCountries :=
   call kGetUserConfigFunc with ('commonCountries);
if ClassOf(ROM_Countries) = 'frame then
   // on a 1.x unit
   labelCommands := foreach item in theCountries collect
      ROM_Countries.(item).name;
else
This would give a nice pop-up menu of countries on a 1.x unit. Why doesn't it work?

A This is a subtle problem. In Newton Toolkit 1.5 and later there are certain functions called constant functions that will evaluate at compile time when their arguments are constant. The most common ones are GetLayout, which will return a reference to another Newton Toolkit layout, and LocObj. The ClassOf function is another one of these.

At compile time, a magic pointer is considered a constant value. That means that the ClassOf call in your conditional is executing at compile time. Of course, there's no Newton device around at compile time, so Newton Toolkit is unable to dereference the magic pointer. Hence the error.

One workaround is to set a local to the value of the magic pointer and use that local in your conditional. This works because the value of the argument to ClassOf is no longer a constant, so it will not be called at compile time.

local mpCountries := ROM_Countries;
if ClassOf(mpCountries) = 'frame then
Q My communications program has a number of standard packets of information. I'm trying to set up constants for each of these standard packets. However, for the packet
constant kHaltAndCatchFireMessage := "\u102cff1003";
Newton Toolkit complains that there's an "odd number of digits between \u's." I count ten, which looks even to me. Does Newton Toolkit need a remedial math course?

A Actually, Newton Toolkit is doing fine in math, but it should say "bytes" instead of "digits." There are ten hex digits in your string, but there are two hex digits per byte, so your string is five bytes long. Since Unicode is a double-byte representation, there are four hex digits per Unicode character. You have ten hex digits, or two and a half Unicode characters, which is an invalid Unicode string.

You can either add two more hex digits to your string or use the MakeBinary and Stuff... functions. If you're dealing with data that's not strings, the latter method is the best one for compatibility. It's also likely to keep you saner.

Q I'm trying to dial the following number using a Newton Fax Modem with my MessagePad 130: "18005551234,,,,,,,,1,,,,408-555-1234,,,,123-456-789-123,,,".I get an error -16013 in my communications code whenever I do this. I need to use the long string because it contains a calling card number. My modem dials correctly and the modem at the other end picks up. I even hear the chirping whistle of exchanging bits. But suddenly things just stop and the error occurs. Any clues?

A Yes. First star on the right, then straight on till morning. But that's a different story. In answer to your question, it looks as though you're timing out on the connection attempt. Modems have a set amount of time to establish a connection, and the commas are reducing the time they have. Each of the commas will insert a delay into the dialing. For most modems, the time for each comma is controlled by register S08 and usually defaults to 2 seconds. You have 19 commas, so that's 38 seconds, which leaves very little time for the modems to sync up (the chirping whistle exchange you're hearing).

The solution is to increase the timeout of the modem to a more reasonable value. When you're thinking about the timeout, remember that each digit will take around 95 milliseconds to dial. There will also be a line connection time of about 2 seconds, a ring time of a few seconds, and the final sync-up or negotiation time of 2 to 15 seconds. You should increase your timeout values to at least 60 seconds. If that doesn't work, add 30-second increments. You can do a binary search to narrow it down to an optimal value.

To set the timeout for the modem, use 60 for the waitForCarrier (sixth) argument of the kCMOModemDialing option. The following bit of code will do this:

// make a modem option data structure based on user preferences
local option := MakeModemOption();
// modify the timeout value
option.data.arglist[6] := 60;
// set that option in your endpoint
ep:Option(option);
Q How can I tell whether a tap is the first of a double tap?

A Unfortunately, the RUM (Read User Mind) ASIC didn't get completed in time for Newton 2.0 OS, so we were unable to implement the IsFirstTap global function. We also looked at a wireless link to one of the 900-number pay-by-the-minute psychic lines but couldn't figure out how to bill the user.

But seriously, you can't tell. The best you can do is to hold off processing the first tap for some amount of time. If you receive another tap in that time, it's a double tap. The drawback is that if it isn't a double tap, you've lost the unit parameter from the first tap, since you can't save this parameter. The other option is to follow a user interface guideline: Make the second tap an extension of the functionality that happens with the first tap. Then there's no need to handle the first tap in a special way.

Q We have a problem with union soups. We have an application that creates soups and transfers them to a PC. The soups can get sent down to a different MessagePad. If the user inserts a storage card and selects it as the default store, we can't successfully add an item to the soup. Our code does a GetUnionSoupAlways, then tries to add an entry using AddToDefaultStoreXmit. The Newton throws an exception that tells us there's no soupDef. We're sure that the soup doesn't exist on the store, but we thought that GetUnionSoupAlways creates the soup if you try to add something. One thing we thought of was to use RegUnionSoup, but our transfer application doesn't know what the soupDef is. Is there a way to copy a soupDef from one store to another or to get the soupDef from an existing soup?

A Well, first you need some good onions, then some stale French bread, Gruyère cheese...oh, sorry, I thought you said "onion soup."

For a union soup to work properly in Newton 2.0 OS, a soupDef must exist in at least one of two places: it can be registered with the OS via RegUnionSoup, or it can exist within a soup that's on a mounted store. GetUnionSoupAlways should fail if there's no soupDef present. However, in the current release of the Newton 2.0 OS ROMs it doesn't. This means the problem is deferred until you first try to add an entry, which is when the OS tries to create the soup but can't find the soupDef. That's why you get the error on the call to AddToDefaultStoreXmit. Of course, this doesn't help you, but there are a few options:

  • Make sure that a soupDef is registered, via RegUnionSoup.

  • Make sure that an actual soup exists on some store and that that soup contains an embedded soupDef. The soup doesn't actually have to have any entries. You can use the CreateSoupFromSoupDef function or the GetMember soup message to do this. For example:
RegUnionSoup(kMySoupDef):GetMember(GetStores()[0]);
  • Don't use union soups; instead, have your download application just send the store either the CreateSoupXmit or the GetSoup message.

  • Write some smart code that checks to see if a soup with the same name exists on any store and duplicate that soup on the new default store. If you use GetIndexes/CreateSoupXmit and GetAllInfo/SetAllInfoXmit, you should be able to make a reasonably similar soup.
Unfortunately, there's no supported way to directly access the soupDef of an existing soup.

Q I have an application that performs some lengthy initializations in the installScript. I need a slip to come up and inform the user that this action is occurring. The problem is that the BuildContext slip I create at the beginning of the installScript doesn't show up when the installScript is running. How can I get a slip to come up in my installScript?

A I assume that you do something like create the slip, send the slip an Open message, and then do a tight loop with some initializations. If so, the system has probably opened your view, but your installScript is still executing. That means the system cannot refresh the display.

One possible approach is to call RefreshViews to force the system to update the display. However, if your progress indication is dynamic, you'll have to call RefreshViews each time you change the progress slip. A better approach is to use the DoProgress call, which provides a standard "Your Newton device is doing something" interface for the user. You may also want to do your initialization in a deferred action.

Q I'd like to add another item to the address picker pop-up list in my "To:," "Cc:," and "Bcc:" pickers that would allow the user to create an e-mail address without adding it to the Names soup. The user interface reasoning behind wanting to do this is to avoid cluttering the Names soup with addresses that are used only once. I've successfully added an item to the picker and caught the pickActionScript for it. The pick item that I want to use to add this temporary name appears in the protoAddressPicker pop-up list. Now I want to bring up an editor and add my temporary item. I tried the call

GetDataDefs('|nameRef.email|):New(tapInfo, self);
from my protoAddressPicker's pickActionScript, but I got an exception: Object {class: nameRef.email, name: "E-Mail addresses", preferredRouting: [string.email], ...} is read-only. Why can't I create a new data object with this?

A Usually answers to these questions are reasonably self-contained; this is an exception. Before you can understand this answer, you really need to read up on list pickers and data, or you'll be tripped up by the subtle differences between nameRefs and dataDefs.

The transport system uses a structure called a nameRef for information on where to send things. It so happens that nameRefs use the data definition registry as a repository. However, a nameRef is a different beastie from a dataDef. To create a new empty nameRef structure, you can use the call

GetDataDefs('|nameRef.email|):MakeNameRef(tapInfo, self);
Then you can use some sort of floating editor to enter the values. I suggest using a protoFloatNGo that contains a newtFalseEntryView and then appropriate slot views for the fields of the nameRef that you want to edit.

The llama is the unofficial mascot of the Developer Technical Support group in Apple's Newton Systems Group. Send your Newton-related questions to dr.llama@newton.apple.com. The first time we use a question from you, we'll send you a T-shirt.

Thanks to jXopher Bell, Henry Cate, Bob Ebert, David Fedor, Ryan Robertson, Jim Schram, Maurice Sharp, and Bruce Thompson for these answers.

If you need more answers, check out http://dev.info.apple.com/newton on the World Wide Web.

 
AAPL
$99.76
Apple Inc.
+2.09
MSFT
$44.08
Microsoft Corpora
+0.45
GOOG
$520.84
Google Inc.
+9.67

MacTech Search:
Community Search:

Software Updates via MacUpdate

RestoreMeNot 2.0.3 - Disable window rest...
RestoreMeNot provides a simple way to disable the window restoration for individual applications so that you can fine-tune this behavior to suit your needs. Please note that RestoreMeNot is designed... Read more
Macgo Blu-ray Player 2.10.9.1750 - Blu-r...
Macgo Mac Blu-ray Player can bring you the most unforgettable Blu-ray experience on your Mac. Overview Macgo Mac Blu-ray Player can satisfy just about every need you could possibly have in a Blu-ray... Read more
Apple iOS 8.1 - The latest version of Ap...
The latest version of iOS can be downloaded through iTunes. Apple iOS 8 comes with big updates to apps you use every day, like Messages and Photos. A whole new way to share content with your family.... Read more
TechTool Pro 7.0.5 - Hard drive and syst...
TechTool Pro is now 7, and this is the most advanced version of the acclaimed Macintosh troubleshooting utility created in its 20-year history. Micromat has redeveloped TechTool Pro 7 to be fully 64... Read more
PDFKey Pro 4.0.2 - Edit and print passwo...
PDFKey Pro can unlock PDF documents protected for printing and copying when you've forgotten your password. It can now also protect your PDF files with a password to prevent unauthorized access and/... Read more
Yasu 2.9.1 - System maintenance app; per...
Yasu was originally created with System Administrators who service large groups of workstations in mind, Yasu (Yet Another System Utility) was made to do a specific group of maintenance tasks... Read more
Hazel 3.3 - 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... Read more
Autopano Giga 3.7 - Stitch multiple imag...
Autopano Giga allows you to stitch 2, 20, or 2,000 images. Version 3.0 integrates impressive new features that will definitely make you adopt Autopano Pro or Autopano Giga: Choose between 9... Read more
MenuMeters 1.8 - CPU, memory, disk, and...
MenuMeters is a set of CPU, memory, disk, and network monitoring tools for Mac OS X. Although there are numerous other programs which do the same thing, none had quite the feature set I was looking... Read more
Coda 2.5 - One-window Web development su...
Coda is a powerful Web editor that puts everything in one place. An editor. Terminal. CSS. Files. With Coda 2, we went beyond expectations. With loads of new, much-requested features, a few... Read more

Latest Forum Discussions

See All

This Week at 148Apps: October 13-17, 201...
Expert App Reviewers   So little time and so very many apps. What’s a poor iPhone/iPad lover to do? Fortunately, 148Apps is here to give you the rundown on the latest and greatest releases. And we even have a tremendous back catalog of reviews; just... | Read more »
Angry Birds Transformers Review
Angry Birds Transformers Review By Jennifer Allen on October 20th, 2014 Our Rating: :: TRANSFORMED BIRDSUniversal App - Designed for iPhone and iPad Transformed in a way you wouldn’t expect, Angry Birds Transformers is a quite... | Read more »
GAMEVIL Announces the Upcoming Launch of...
GAMEVIL Announces the Upcoming Launch of Mark of the Dragon Posted by Jessica Fisher on October 20th, 2014 [ permalink ] Mark of the Dragon, by GAMEVIL, put | Read more »
Interview With the Angry Birds Transform...
Angry Birds Transformers recently transformed and rolled out worldwide. This run-and-gun title is a hit with young Transformers fans, but the ample references to classic Transformers fandom has also earned it a place in the hearts of long-time... | Read more »
Find Free Food on Campus with Ypay
Find Free Food on Campus with Ypay Posted by Jessica Fisher on October 20th, 2014 [ permalink ] iPhone App - Designed for the iPhone, compatible with the iPad | Read more »
Strung Along Review
Strung Along Review By Jordan Minor on October 20th, 2014 Our Rating: :: GOT NO STRINGSUniversal App - Designed for iPhone and iPad A cool gimmick and a great art style keep Strung Along from completely falling apart.   | Read more »
P2P file transferring app Send Anywhere...
File sharing services like Dropbox have security issues. Email attachments can be problematic when it comes to sharing large files. USB dongles don’t fit into your phone. Send Anywhere, a peer-to-peer file transferring application, solves all of... | Read more »
Zero Age Review
Zero Age Review By Jordan Minor on October 20th, 2014 Our Rating: :: MORE THAN ZEROiPad Only App - Designed for the iPad With its mind-bending puzzles and spellbinding visuals, Zero Age has it all.   | Read more »
Hay Ewe Review
Hay Ewe Review By Campbell Bird on October 20th, 2014 Our Rating: :: SAVE YOUR SHEEPLEUniversal App - Designed for iPhone and iPad Pave the way for your flock in this line drawing puzzle game from the creators of Worms.   | Read more »
My Very Hungry Caterpillar (Education)
My Very Hungry Caterpillar 1.0.0 Device: iOS Universal Category: Education Price: $3.99, Version: 1.0.0 (iTunes) Description: Care for your very own Very Hungry Caterpillar! My Very Hungry Caterpillar will captivate you as he crawls... | Read more »

Price Scanner via MacPrices.net

Deals on 2011 13-inch MacBook Airs, from $649
Daily Steals has the Mid-2011 13″ 1.7GHz i5 MacBook Air (4GB/128GB) available for $699 with a 90 day warranty. The Mid-2011 13″ 1.7GHz i5 MacBook Air (4GB/128GB SSD) is available for $649 at Other... Read more
2013 15-inch 2.0GHz Retina MacBook Pro availa...
B&H Photo has leftover previous-generation 15″ 2.0GHz Retina MacBook Pros now available for $1599 including free shipping plus NY sales tax only. Their price is $400 off original MSRP. B&H... Read more
Updated iPad Prices
We’ve updated our iPad Air Price Tracker and our iPad mini Price Tracker with the latest information on prices and availability from Apple and other resellers, including the new iPad Air 2 and the... Read more
Apple Pay Available to Millions of Visa Cardh...
Visa Inc. brings secure, convenient payments to iPad Air 2 and iPad mini 3as well as iPhone 6 and 6 Plus. Starting October 20th, eligible Visa cardholders in the U.S. will be able to use Apple Pay,... Read more
Textkraft Pocket – the missing TextEdit for i...
infovole GmbH has announced the release and immediate availability of Textkraft Pocket 1.0, a professional text editor and note taking app for Apple’s iPhone. In March 2014 rumors were all about... Read more
C Spire to offer iPad Air 2 and iPad mini 3,...
C Spire on Friday announced that it will offer iPad Air 2 and iPad mini 3, both with Wi-Fi + Cellular, on its 4G+ LTE network in the coming weeks. C Spire will offer the new iPads with a range of... Read more
Belkin Announces Full Line of Keyboards and C...
Belkin International has unveiled a new lineup of keyboard cases and accessories for Apple’s newest iPads, featuring three QODE keyboards and a collection of thin, lightweight folios for both the... Read more
Verizon offers new iPad Air 2 preorders for $...
Verizon Wireless is accepting preorders for the new iPad Air 2, cellular models, for $100 off MSRP with a 2-year service agreement: - 16GB iPad Air 2 WiFi + Cellular: $529.99 - 64GB iPad Air 2 WiFi... Read more
Price drops on refurbished Mac minis, now ava...
The Apple Store has dropped prices on Apple Certified Refurbished previous-generation Mac minis, with models now available starting at $419. Apple’s one-year warranty is included with each mini, and... Read more
Apple refurbished 2014 MacBook Airs available...
The Apple Store has Apple Certified Refurbished 2014 MacBook Airs available for up to $180 off the cost of new models. An Apple one-year warranty is included with each MacBook, and shipping is free.... Read more

Jobs Board

Project Manager / Business Analyst, WW *Appl...
…a senior project manager / business analyst to work within our Worldwide Apple Fulfillment Operations and the Business Process Re-engineering team. This role will work 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
Position Opening at *Apple* - Apple (United...
…customers purchase our products, you're the one who helps them get more out of their new Apple technology. Your day in the Apple Store is filled with a range of Read more
Position Opening at *Apple* - Apple (United...
**Job Summary** At the Apple Store, you connect business professionals and entrepreneurs with the tools they need in order to put Apple solutions to work in their Read more
Position Opening at *Apple* - Apple (United...
**Job Summary** The Apple Store is a retail environment like no other - uniquely focused on delivering amazing customer experiences. As an Expert, you introduce people Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.