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
$524.94
Apple Inc.
+5.93
MSFT
$40.01
Microsoft Corpora
-0.39
GOOG
$536.10
Google Inc.
-20.44

MacTech Search:
Community Search:

Software Updates via MacUpdate

Tweetbot 1.5.1 - Popular iOS twitter cli...
Tweetbot is a full-featured OS X Twitter client with a lot of personality. Whether it's the meticulously-crafted interface, sounds and animation, or features like multiple timelines and column views... Read more
Mac DVDRipper Pro 4.1.7 - Copy, backup,...
Mac DVDRipper Pro is the DVD backup solution that lets you protect your DVDs from scratches, save your batteries by reading your movies from your hard disk, manage your collection with just a few... Read more
PDFpenPro 6.2 - Advanced PDF toolkit for...
PDFpenPro allows users to edit PDF's easily. Add text, images and signatures. Fill out PDF forms. Merge or split PDF documents. Reorder and delete pages. Even correct text and edit graphics! Create... Read more
PDFpen 6.2 - Edit and annotate PDFs with...
PDFpen allows users to easily edit PDF's. Add text, images and signatures. Fill out PDF forms. Merge or split PDF documents. Reorder and delete pages. Even correct text and edit graphics! Features... Read more
Monolingual 1.5.9 - Remove unwanted OS X...
Monolingual is a program for removing unnecesary language resources from OS X, in order to reclaim several hundred megabytes of disk space. It requires a 64-bit capable Intel-based Mac and at least... Read more
Maya 2015 - Professional 3D modeling and...
Maya is an award-winning software and powerful, integrated 3D modeling, animation, visual effects, and rendering solution. Because Maya is based on an open architecture, all your work can be scripted... Read more
Starcraft II: Wings of Liberty 1.1.1.180...
Download the patch by launching the Starcraft II game and downloading it through the Battle.net connection within the app. Starcraft II: Wings of Liberty is a strategy game played in real-time. You... Read more
Sibelius 7.5.0 - Music notation solution...
Sibelius is the world's best-selling music notation software for Mac. It is as intuitive to use as a pen, yet so powerful that it does most things in less than the blink of an eye. The demo includes... Read more
Typinator 5.9 - Speedy and reliable text...
Typinator turbo-charges your typing productivity. Type a little. Typinator does the rest. We've all faced projects that require repetitive typing tasks. With Typinator, you can store commonly used... Read more
MYStuff Pro 2.0.16 - Create inventories...
MYStuff Pro is the most flexible way to create detail-rich inventories for your home or small business. Add items to MYStuff by dragging and dropping existing information, uploading new images, or... Read more

Latest Forum Discussions

See All

Have a Special Dead Trigger 2 Easter Bas...
Have a Special Dead Trigger 2 Easter Basket Full of Goodies, Courtesy of Madfinger Games Posted by Rob Rich on April 18th, 2014 [ permalink ] Dead Trigger 2 | Read more »
Zynga Launches Brand New Farmville Exper...
Zynga Launches Brand New Farmville Experience with Farmville 2: Country Escape Posted by Tre Lawrence on April 18th, 2014 [ permalink ] | Read more »
David. Review
David. Review By Cata Modorcea on April 18th, 2014 Our Rating: :: MINIMALISTIC IN A DIFFERENT WAYUniversal App - Designed for iPhone and iPad David is a minimalistic game wrapped inside of a soothing atmosphere in which the hero... | Read more »
Eyefi Unveils New Eyefi Cloud Service Th...
Eyefi Unveils New Eyefi Cloud Service That Allows Users to Share Media Across Personal Devices Posted by Tre Lawrence on April 18th, 2014 [ permalink ] | Read more »
Tales from the Dragon Mountain: The Lair...
Tales from the Dragon Mountain: The Lair Review By Jennifer Allen on April 18th, 2014 Our Rating: :: STEADY ADVENTURINGiPad Only App - Designed for the iPad Treading a safe path, Tales from the Dragon Mountain: The Lair is a... | Read more »
Yahoo Updates Flickr App with Advanced E...
Yahoo Updates Flickr App with Advanced Editing Features and More Posted by Tre Lawrence on April 18th, 2014 [ permalink ] | Read more »
My Incredible Body - A Kid's App to...
My Incredible Body - A Kid's App to Learn about the Human Body 1.1.00 Device: iOS Universal Category: Education Price: $2.99, Version: 1.1.00 (iTunes) Description: Wouldn’t it be cool to look inside yourself and see what was going on... | Read more »
Trials Frontier Review
Trials Frontier Review By Carter Dotson on April 18th, 2014 Our Rating: :: A ROUGH LANDINGUniversal App - Designed for iPhone and iPad Trials Frontier finally brings the famed stunt racing franchise to mobile, but how much does its... | Read more »
Evernote Business Notebook by Moleskin I...
Evernote Business Notebook by Moleskin Introduced – Support Available in Evernote for iOS Posted by Tre Lawrence on April 18th, 2014 [ permalink ] | Read more »
Sparkle Unleashed Review
Sparkle Unleashed Review By Jennifer Allen on April 18th, 2014 Our Rating: :: CLASSY MARBLE FLINGINGUniversal App - Designed for iPhone and iPad It’s a concept we’ve seen before, but Sparkle Unleashed is a solidly enjoyable orb... | Read more »

Price Scanner via MacPrices.net

iMacs on sale for up to $160 off MSRP this we...
Best Buy has iMacs on sale for up to $160 off MSRP for a limited time. Choose free home shipping or free instant local store pickup (if available). Prices are valid for online orders only, in-store... Read more
iPad Airs on sale this weekend for up to $100...
Best Buy has WiFi iPad Airs on sale for $50 off MSRP and WiFi + Cellular iPad Airs on sale for $100 off MSRP on their online store for a limited time, with prices now starting at $449. Choose free... Read more
Apple restocks refurbished Mac minis starting...
The Apple Store has restocked Apple Certified Refurbished Mac minis for up to $150 off the cost of new models. Apple’s one-year warranty is included with each mini, and shipping is free: - 2.5GHz Mac... Read more
Hyundai Brings Apple CarPlay To The 2015 Sona...
Hyundai Motor America has announced it will bring Apple CarPlay functionality to the 2015 Sonata. CarPlay is pitched as a smarter, safer and easier way to use iPhone in the car and gives iPhone users... Read more
Updated iPads Coming Sooner Than We Had Thoug...
MacRumors, cites KGI securities analyst Ming Chi Kuo, well-respected as an Apple product prognisticator, saying that Apple will introduce an upgraded iPad Air and iPad mini in 2014/Q3, meaning the... Read more
Toshiba Unveils New High And Low End Laptop M...
Toshiba has announced new laptop models covering both the high-end and low-end of the notebook computer spectrum. Toshiba 4K Ultra HD Laptop Toshiba’s new Satellite P55t features one of the world’s... Read more
Save up to $270 with Apple refurbished 13-inc...
The Apple Store has Apple Certified Refurbished October 2013 13″ Retina MacBook Pros available starting at $1099, with models up to $270 off MSRP. Apple’s one-year warranty is standard, and shipping... Read more
Apple now offering refurbished iPad mini with...
The Apple Store has Certified Refurbished 2nd generation iPad minis with Retina Displays now available starting at $339. Apple’s one-year warranty is included with each model, and shipping is free.... Read more
Microsoft Blinks – Drops Microsoft Office 365...
Microsoft has dropped the annual subscription fee for Microsoft Office 365 Personal – which is needed in order to create and edit documents in Microsoft Office for iPad. However, Apple’s iOS and OS X... Read more
New AVG Vault Apps for iOS and Android Help K...
AVG Technologies N.V. an online security company for 177 million active users, has announced the launch of its latest mobile application, AVG Vault. The free app introduces an innovative user... 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
*Apple* Retail - Manager - Holyoke - Apple I...
Job Summary Keeping an Apple Store thriving requires a diverse set of leadership skills, and as a Manager, you’re a master of them all. In the store’s fast-paced, Read more
*Apple* Retail - Manager - Apple (United Sta...
Job SummaryKeeping an Apple Store thriving requires a diverse set of leadership skills, and as a Manager, you're a master of them all. In the store's fast-paced, dynamic 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* Retail - Market Leader - Cincinnati...
…challenges of developing individuals, building teams, and affecting growth across Apple Stores. You demonstrate successful leadership ability - focusing on excellence Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.