TweetFollow Us on Twitter

CamelBones

Volume Number: 19 (2003)
Issue Number: 1
Column Tag: Mac OS X

CamelBones

Creating GUI-based apps with Perl

by Rich Morin

Sherm Pendley bills CamelBones as "An Objective-C/Perl bridge framework". The web page goes on to say "CamelBones is a framework that allows many types of Cocoa programs to be written entirely in Perl. It also provides a high-level object-oriented wrapper around an embedded Perl interpreter, so that Cocoa programs written in Objective-C can easily make use of code and libraries written in Perl."

Jumping from the general to the particular, CamelBones allows a Perl scripter to create GUI-based apps, with only a modicum of pain (read, Objective-C :-). Because the scripter can use Interface Builder, the graphic layout is painless, quick, and likely to yield attractive results.

Limitations

Sherm says that CamelBone's biggest current limitation is inheritance. It's not yet possible to create a Perl sub-class that inherits from an Objective-C sub-class. As a result, CamelBones can't be used for:

  • Document-based applications, which require a subclass of NSDocument.

  • Custom controls and/or cells, which require a subclass of one of the many NSControl or NSCell descendants, respectively.

This limitation will be addressed in the next version (0.3), which Sherm expects to have ready by the time this article is in print. Meanwhile, most of the tasks which could be performed by a cub-class can be handled by a Delegation or Notification callback.

CamelBones has some other problems, at least from my perspective. Because the app needs to be "built" (with Project Builder) rather than simply run, the build time becomes a noticeable part of the edit/test cycle. I think that's just the price we pay for using compilers and linkers (:-).

Also, most of the existing Cocoa documentation assumes that you're using Objective-C. This means that you have to have a reading knowledge of Objective-C, as well as the ability to turn method prototypes and example code into their Perl equivalents. I find this livable, however, and help is on the way for both problems

Getting Started

Assuming that you already have OSX and Apple's Developer Tools installed, adding CamelBones is quite simple. Go to http//camelbones.sf.net, download the distribution, and install it! At this writing, the documentation is still a bit sketchy, but the author plans to improve it Real Soon Now, so it may be in significantly better shape by the time you see it.

The package uses a standard installer, so installation is quite easy. I'd suggest that you choose the "Custom" install, so that you can get the source code (why not?). I haven't looked at the code, but I assume that it's a combination of Objective-C and Perl. Nice to have around, if you get frustrated by some peculiarity or simply become curious about how it all works.

If you are thinking about using CamelBones in a proprietary offering, you may want to look over the license a bit. CamelBones is released under the GNU Project's "Lesser General Public License" (LGPL). Briefly, the LGPL allows your app to use CamelBones without any requirement that the author provide the source code for the application (though with Perl, source distribution is the default case). On the other hand, any changes you make to CamelBones itself must be made available to anyone who gets the "binaries".

Once you have CamelBones installed, I strongly suggest that you skim the documentation and walk through the HowTo examples. As a newcomer to Interface Builder and Project Builder, this taught me a bit about the capabilities and operation of each. Even if you are expert at IB and PB, the examples will give you an idea of what kind of Perl code CamelBones expects.

In brief, however, Perl code for use with CamelBones looks pretty much like Perl code to work with any object-oriented API. Stuff like:

sub sayHello {
    my ($self, $sender) = @_;
    $self->{'TextLabel'}->setStringValue("Hello");
    NSLog("Hello, world!");
}

One peculiarity, discussed in the CamelBones web pages, is that CamelBones doesn't (yet ) provide "toll-free" bridging of Perl hashes and lists to Cocoa's collection classes. Consequently, the Perl code has to deal with the Cocoa collections explicitly. Instead of writing:

my %hash;
my $key     = 'abc';
$hash{$key} = 'def';
printf("key=%s, value=%s\n",
  $key, $hash{$key});

you have to write something like:

my $hash = NSMutableDictionary->alloc->init;
my $key  = 'abc';
$hash->setObject_forKey($key, 'def');
printf("key=%s, value=%s\n",
  $key, $hash->objectForKey($key));

Also, because Objective-C doesn't provide automatic (Perl-style) garbage collection, you may need to explicitly reserve and release any Objective-C objects which you create. This looks pretty tedious, to my Perl-accustomed eyes, but I'm consoled by the facts that (a) I only have to use Cocoa collections to access Cocoa-specific items and (b) relief is said to be on the way.

Packaging Issues

Ease of distribution and installation has been a CamelBones priority from the start. All that the end user needs is a copy of CamelBones.framework. By default, applications look for this in /Library/Frameworks, so the easiest thing to do is to create an installer package that will make sure that the framework can be found there.

But, if a developer wants a drag-and-drop install and is willing to rebuild the framework with the appropriate Project Builder options, the framework can be embedded in the application bundle itself. CPAN (Comprehensive Perl Archive Network) modules can also be included in the application bundle, eliminating another common source of pain for end users of Perl programs.

Version Creep

The CamelBones framework is linked against the Perl interpreter (Version 5.6.0) that is shipped with OSX. Sherm has gotten reports that Perl 5.6.1 works fine, as long as it's compiled and installed identically to the original 5.6.0, but 5.8.0 definitely doesn't. So, if you have added Perl 5.8.0 to your system, you may have to rebuild any CamelBones apps you receive.

As time goes on, Apple is quite likely to release Perl 5.8.0 (or whatever) as an update to OSX. Unless a workaround is found, this will cause all 5.6.0-based CamelBones apps to break. Fortunately, some Very Bright People are looking into the matter, so a fix is likely.

Resources

Perl wizard Dan Sugalski is currently writing "Programming Cocoa Applications with Perl" for O'Reilly, but a publication date has not yet been established. The book will cover CamelBones in depth, however, so watch for it! In the meanwhile, Dan promises to put up some example code on the CamelBones web site.

Notwithstanding tha fact that they assume Objective-C usage, most books on Cocoa, IB, and PB are relevant to CamelBones Here are some you might want to look over:

    "Building Cocoa Applications: A Step-by-Step Guide"

    Garfinkel and Mahoney

    O'Reilly and Associates, 2002

    ISBN 0-596-00235-1

    "Cocoa Cookbook for Mac OS X"

    Bill Cheeseman

    Peachpit, 2002

    ISBN 0-201-87801-1

    "Cocoa Programming for Mac OS X"

    Aaron Hillegass

    Addison-Wesley, 2001

    ISBN 0-201-72683-1

    "Learning Cocoa with Objective-C", second edition

    James Duncan Davidson

    O'Reilly and Associates, 2002

    ISBN 0-596-00301-3

There is also a 200+ page rundown on Objective-C, right on your Mac OS X system (/Developer/Documentation/Cocoa/ObjectiveC/ObjC.pdf). You should also consider joining the MacOSX-Perl email list, which covers CamelBones and other Perlish topics on Mac OS X. Send email to macosx-subscribe@perl.org to get started.

Although Apple provides documentation on the AppKit and Foundation frameworks, it can be tedious to navigate. So, pick up a copy of Hoshi Takanori's Cocoa Browser app (http://homepage2.nifty.com/hoshi-takanori/cocoa-browser). This will let you browse the Objective-C method descriptions in a speedy, hierarchically-based manner.

As noted above, you will still have to convert the method synopses into Perl format, but that's life. Actually, I'm actually working on a conversion app, but you'll have to wait until next month to read about it. Until then, happy hacking...


Rich Morin has been using computers since 1970, Unix since 1983, and Mac-based Unix since 1986 (when he helped Apple create A/UX 1.0). When he isn't writing this column, Rich runs Prime Time Freeware (www.ptf.com), a publisher of books and CD-ROMs for the Free and Open Source software community. Feel free to write to Rich at rdm@ptf.com.

 
AAPL
$118.93
Apple Inc.
-0.07
MSFT
$47.81
Microsoft Corpora
+0.06
GOOG
$541.83
Google Inc.
+1.46

MacTech Search:
Community Search:

Software Updates via MacUpdate

Adobe Photoshop Elements 13.0 - Consumer...
Adobe Photoshop Elements 12--the #1 selling consumer photo editing software--helps you edit pictures with powerful, easy-to-use options and share them via print, the web, Facebook, and more.Version... Read more
Skype 7.2.0.412 - Voice-over-internet ph...
Skype allows you to talk to friends, family and co-workers across the Internet without the inconvenience of long distance telephone charges. Using peer-to-peer data transmission technology, Skype... Read more
HoudahSpot 3.9.6 - Advanced file search...
HoudahSpot is a powerful file search tool built upon MacOS X Spotlight. Spotlight unleashed Create detailed queries to locate the exact file you need Narrow down searches. Zero in on files Save... Read more
RapidWeaver 6.0.3 - Create template-base...
RapidWeaver is a next-generation Web design application to help you easily create professional-looking Web sites in minutes. No knowledge of complex code is required, RapidWeaver will take care of... Read more
iPhoto Library Manager 4.1.10 - Manage m...
iPhoto Library Manager lets you organize your photos into multiple iPhoto libraries. Separate your high school and college photos from your latest summer vacation pictures. Or keep some photo... Read more
iExplorer 3.5.1.9 - View and transfer al...
iExplorer is an iPhone browser for Mac lets you view the files on your iOS device. By using a drag and drop interface, you can quickly copy files and folders between your Mac and your iPhone or... Read more
MacUpdate Desktop 6.0.3 - Discover and i...
MacUpdate Desktop 6 brings seamless 1-click installs and version updates to your Mac. With a free MacUpdate account and MacUpdate Desktop 6, Mac users can now install almost any Mac app on macupdate.... Read more
SteerMouse 4.2.2 - Powerful third-party...
SteerMouse is an advanced driver for USB and Bluetooth mice. It also supports Apple Mighty Mouse very well. SteerMouse can assign various functions to buttons that Apple's software does not allow,... Read more
iMazing 1.1 - Complete iOS device manage...
iMazing (was DiskAid) is the ultimate iOS device manager with capabilities far beyond what iTunes offers. With iMazing and your iOS device (iPhone, iPad, or iPod), you can: Copy music to and from... Read more
PopChar X 7.0 - Floating window shows av...
PopChar X helps you get the most out of your font collection. With its crystal-clear interface, PopChar X provides a frustration-free way to access any font's special characters. Expanded... Read more

Latest Forum Discussions

See All

Castaway Paradise – Tips, Tricks, and St...
Ahoy there, castaways: Were you curious about our own thoughts regarding this pristine shipwreck? Check out our Castaway Paradise review! Castaway Paradise is out for iOS, finally giving mobile gamers the opportunity to enjoy the idyllic lifestyle... | Read more »
7 tips to get ahead of the competition i...
7 tips to get ahead of the competition in Dynasty of Dungeons Posted by Simon Reed on November 28th, 2014 [ permalink ] Playcrab has launched their action-packed new dungeon crawler, Dynasty of Dungeons, today. | Read more »
Monster Strike Review
Monster Strike Review By Campbell Bird on November 28th, 2014 Our Rating: :: BILLIARD STRATEGYUniversal App - Designed for iPhone and iPad Collect monsters and battle by flinging them across the battlefield in this strangely... | Read more »
Proun+ Review
Proun+ Review By Jennifer Allen on November 28th, 2014 Our Rating: :: TWITCHY RACINGUniversal App - Designed for iPhone and iPad Twitchy racing aplenty in Proun+, an enjoyably tricky title.   | Read more »
Lucha Amigos (Games)
Lucha Amigos 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Forget Ninja Turtles, and meet Wrestlers Turtles! Crazier, Spicier and…Bouncier! Sling carapaces of 7 Luchadores to knock all... | Read more »
Record of Agarest War Zero (Games)
Record of Agarest War Zero 1.0 Device: iOS Universal Category: Games Price: $7.99, Version: 1.0 (iTunes) Description: HyperDevbox Holiday Turkey Black Friday Special Pricing! To celebrate the opening of the holiday season HyperDevbox... | Read more »
Raby (Games)
Raby 1.0.3 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.3 (iTunes) Description: ***WARNING - Raby runs on: iPhone 5, iPhone 5C, iPhone 5S, iPhone 6, iPhone 6 Plus, iPad Mini Retina, iPad Mini 3, iPad 4, iPad Air,... | Read more »
Oddworld: Stranger's Wrath (Games)
Oddworld: Stranger's Wrath 1.0 Device: iOS Universal Category: Games Price: $5.99, Version: 1.0 (iTunes) Description: ** PLEASE NOTE: Oddworld Stranger's Wrath requires at least an iPhone 4S, iPad 2, iPad Mini or iPod Touch 5th gen... | Read more »
Bounce On Back (Games)
Bounce On Back 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: | Read more »
Dwelp (Games)
Dwelp 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: === 50% off for a limited time, to celebrate release === Dwelp is an elegant little puzzler with a brand new game mechanic. To complete a... | Read more »

Price Scanner via MacPrices.net

Up To 75% Off Infovole Text Apps Over Black F...
Infovole’s entire range of apps, including the Textkraft family of word processors for iPads and iPhones, is being offered at 50-75% off over the Black Friday and Cyber Monday weekend. The five-day... Read more
Black Friday: Up to $60 off Mac minis, NY tax...
 B&H Photo has new 2014 Mac minis on sale for up to $60 off MSRP as part of their Black Friday sale. Shipping is free, and B&H charges NY sales tax only: - 1.4GHz Mac mini: $449.99 $50 off... Read more
Black Friday: 27-inch 5K iMac for $2299, save...
 B&H Photo continues to offer Black Friday sale prices on the 27″ 3.5GHz 5K iMac, in stock today and on sale for $2299 including free shipping plus NY sales tax only. Their price is $200 off MSRP... Read more
Karalux Announces 24K Gold-Plated iPhone 6
Karalux, a Vietnam-based jewellery firm, has launched a unique 24 karat gold-plated iPhone 6 version with gold-cast monolithic dragon on its back panel. The real 24 karat gold plated enclosure doesn’... Read more
Black Friday: 13-inch 2.6GHz Retina MacBook P...
 B&H Photo has lowered their price for the 13″ 2.6GHz/128GB Retina MacBook Pro to $1159 for Black Friday. That’s $140 off MSRP, and it’s the lowest price for this model (except for Apple’s $1099... Read more
View all the Black Friday sales on our Mac Pr...
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. View Black Friday sale prices at a... Read more
Black Friday: 11-inch MacBook Air for $779, s...
 Best Buy has lowered their price for the 2014 11″ 1.4GHz/128GB MacBook Air to $779.99 for Black Friday. That’s $120 off MSRP. Choose free shipping or free local store pickup (if available). Sale... Read more
Apple Store Black Friday sale for 2014: $100...
BLACK FRIDAY The Apple Store has posted their Black Friday deals for 2014. Receive a $100 PRODUCT(RED) branded iTunes gift card with the purchase of select Macs, $50 with iPads, and $25 with iPods,... Read more
Black Friday: 15% off iTunes Gift Cards
Staples is offering 15% off $50 and $100 iTunes Gift Cards on their online store as part of their Black Friday sale. Click here for more information. Shipping is free. Best Buy is offering $100... Read more
BEVL Releases Dock Tailored for iPhone 6 and...
Seattle based BEVL has released their first product: an iPhone dock that is divergent in build quality, rock-solid function and visual simplicity to complement the iPhone. BEVL is now accepting... Read more

Jobs Board

*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
Senior Event Manager, *Apple* Retail Market...
…This senior level position is responsible for leading and imagining the Apple Retail Team's global event strategy. Delivering an overarching brand story; in-store, Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.