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
$101.32
Apple Inc.
+0.74
MSFT
$45.15
Microsoft Corpora
-0.07
GOOG
$582.56
Google Inc.
-0.81

MacTech Search:
Community Search:

Software Updates via MacUpdate

calibre 2.0.0 - Complete e-library manag...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital... Read more
Apple iMovie 10.0.5 - Edit personal vide...
With an all-new design, Apple iMovie lets you enjoy your videos like never before. Browse your clips more easily, instantly share your favorite moments, and create beautiful HD movies and Hollywood-... Read more
Apple Keynote 6.2.2 - Apple's prese...
Apple Keynote makes it simple to create and deliver beautiful presentations. Powerful tools and dazzling effects bring your ideas to life. You can work seamlessly between Mac and iOS devices. And... Read more
Apple Numbers 3.2.2 - Apple's sprea...
With Apple Numbers, sophisticated spreadsheets are just the start. The whole sheet is your canvas. Just add dramatic interactive charts, tables, and images that paint a revealing picture of your data... Read more
OpenOffice 4.1.1 - Free and open-source...
OpenOffice.org is both an Open Source product and a project. The product is a multi-platform office productivity suite. It includes the key desktop applications, such as a word processor,... Read more
Pages 5.2.2 - Apple's word processo...
Apple Pages is a powerful word processor that gives you everything you need to create documents that look beautiful. And read beautifully. It lets you work seamlessly between Mac and iOS devices. And... Read more
Quicken 2015 2.0.1 - Complete personal f...
The new Quicken 2015 helps you manage all your personal finances in one place, so you can see where you're spending and where you can save. Quicken automatically categorizes your financial... Read more
CleanMyMac 2.2.7 - Delete files that was...
CleanMyMac makes space for the things you love. Sporting a range of ingenious new features, CleanMyMac 2 lets you safely and intelligently scan and clean your entire system, delete large, unused... Read more
MacFamilyTree 7.2.4 - Create and explore...
MacFamilyTree gives genealogy a facelift: it's modern, interactive, incredibly fast, and easy to use. We're convinced that generations of chroniclers would have loved to trade in their genealogy... Read more
Videobox 4.1.1 - Download Flash video th...
Videobox allows you to quickly and easily download Flash video from most all of the popular video sites on the internet. Videobox will convert the video into a native Quicktime format so it's ready... Read more

Latest Forum Discussions

See All

Trolls vs Vikings Update Adds Over One H...
Trolls vs Vikings Update Adds Over One Hundred Levels, Reduces Item Cost, and More Posted by Ellis Spice on August 22nd, 2014 [ permalink ] | Read more »
SNK Celebrates the 20th Anniversary of T...
SNK Celebrates the 20th Anniversary of The King of Fighters With a Big Sale Posted by Ellis Spice on August 22nd, 2014 [ permalink ] | Read more »
It Came From Canada: Star Wars: Commande...
With a brand new Star Wars trilogy on the horizon, prepare yourselves for Disney and George Lucas’s space fantasy throwback to be more omnipresent than ever before. So it should come as no surprise that new adventures in that galaxy far, far away... | Read more »
Swing Copters Review
Swing Copters Review By Jordan Minor on August 22nd, 2014 Our Rating: :: DIE TRYINGUniversal App - Designed for iPhone and iPad The creator of Flappy Bird is back with a vengeance.   | Read more »
Beam Me an Update Scotty – Star Trek Tre...
Beam Me an Update Scotty – Star Trek Trexels Receives its Biggest Update Yet Posted by Jessica Fisher on August 22nd, 2014 [ permalink ] | Read more »
The Outcast Review
The Outcast Review By Nadia Oxford on August 22nd, 2014 Our Rating: :: HANDS OFF. WAY OFF.Universal App - Designed for iPhone and iPad It’s easy to see what The Outcast is trying for, but its execution needs a lot of work.   | Read more »
HeroCraft Unveils New iOS Game, Marble D...
HeroCraft Unveils New iOS Game, Marble Duel Posted by Jessica Fisher on August 22nd, 2014 [ permalink ] HeroCraft is developing a new chain popper game called Marble Duel, wh | Read more »
Brain+ Review
Brain+ Review By Nadia Oxford on August 22nd, 2014 Our Rating: :: DIM BULBUniversal App - Designed for iPhone and iPad Brain+ is just another entry in an over-saturated brain-training marketplace – and not a particularly fun entry... | Read more »
The Witcher Battle Arena – New Gameplay...
The Witcher Battle Arena – New Gameplay Trailer Revealed Posted by Jessica Fisher on August 22nd, 2014 [ permalink ] Based in the Witcher universe, | Read more »
Max Gentlemen Review
Max Gentlemen Review By Jennifer Allen on August 22nd, 2014 Our Rating: :: OUTSTAYING ITS WELCOMEiPhone App - Designed for the iPhone, compatible with the iPad Max Gentlemen seems pretty quirky initially but that appeal wears thin... | Read more »

Price Scanner via MacPrices.net

Leftover 15-inch 2.0GHz Retina MacBook Pros a...
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
Pro.Calendar – New Productivity App for iPad...
Austin, Texas based mobile business and productivity app developer LightArrow, Inc. has announced Pro.Calendar, a powerful and intuitive calendar app with eight versatile calendar options including... Read more
SanDisk Ultra II SSD — Supercharge Your Syste...
SanDisk Corporation has announced the new SanDisk Ultra II SSD with enhanced SSD Dashboard. The new drive is designed to deliver a cost-effective and easy upgrade solution for PC owners looking to... Read more
Samsung and Barnes & Noble Introduce New...
Samsung Electronics America and NOOK Media, a subsidiary of Barnes & Noble, Inc. have announced the introduction of the new Samsung Galaxy Tab 4 NOOK, a 7-inch tablet combining Samsung’s leading... Read more
21-inch iMacs on sale for up to $150 off MSRP
B&H Photo has 21″ iMacs on sale for up to $150 off MSRP including free shipping plus NY sales tax only. B&H will also include a free copy of Parallels Desktop software: - 21″ 2.7GHz iMac: $... Read more
27-inch 3.2GHz iMac on sale for $1698, save $...
Abt has the 27″ 3.2GHz iMac on sale for $1698 including free shipping. Their price is $101 off MSRP. Read more
Mac Backup Guru 2.0 Drive Backup/Cloneing Uti...
Mac Backup Guru developer MacDaddy has released Mac Backup Guru 2.0, offering new and enhanced advanced features, such as bootable backups, synchronised volumes and folders, and a Snapshot mode that... Read more
Operate GE’s New Free-Standing KItchen Range...
Think you accidentally left the oven on? Switch it off while on the go. The new free-standing Profile™ Series gas and electric ranges are GE’s second cooking appliances, following their wall oven, to... Read more
Parallels Announces Parallels Desktop 10 for...
The no. 1-selling software for running Windows applications on a Mac becomes an even easier choice for millions of consumers and IT professionals worldwide with the launch of the most powerful... Read more
Apple now offering certified refurbished 2014...
 The Apple Store is now offering Apple Certified Refurbished 2014 MacBook Airs for up to $180 off the cost of new models. An Apple one-year warranty is included with each MacBook, and shipping is... Read more

Jobs Board

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
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...
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
Position Opening at *Apple* - Apple (United...
**Job Summary** As more and more people discover Apple , they visit our stores seeking ways to incorporate our products into their lives. It's your job, as a Store Read more
Position Opening at *Apple* - Apple (United...
…Summary** As a Specialist, you help create the energy and excitement around Apple products, providing the right solutions and getting products into customers' hands. You Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.