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
$102.64
Apple Inc.
+1.58
MSFT
$46.56
Microsoft Corpora
-0.50
GOOG
$581.13
Google Inc.
-6.24

MacTech Search:
Community Search:

Software Updates via MacUpdate

GarageSale 6.8 - Create outstanding eBay...
GarageSale is a slick, full-featured client application for the eBay online auction system. Create and manage your auctions with ease. With GarageSale, you can create, edit, track, and manage... Read more
ScreenFlow 4.5.3 - Create screen recordi...
Save 5% with the MacUpdate coupon code: 68031AE15F -- Buy now! ScreenFlow is powerful, easy-to-use screencasting software for the Mac. With ScreenFlow you can record the contents of your entire... Read more
NeoOffice 2014.3 - Mac-tailored, OpenOff...
NeoOffice is a complete office suite for OS X. With NeoOffice, users can view, edit, and save OpenOffice documents, PDF files, and most Microsoft Word, Excel, and PowerPoint documents. NeoOffice 3.x... Read more
Typinator 6.2 - 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
PopChar X 6.7 - 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
Evernote 5.6.0 - Create searchable notes...
Evernote allows you to easily capture information in any environment using whatever device or platform you find most convenient, and makes this information accessible and searchable at anytime, from... Read more
Monosnap 2.2.2 - Versatile screenshot ut...
Monosnap allows you to save screenshots easily, conveniently, and quickly, sharing them with friends and colleagues at once. It's the ideal choice for anyone who is looking for a smart and fast... Read more
Tunnelblick 3.4beta36 - GUI for OpenVPN...
Tunnelblick is a free, open source graphic user interface for OpenVPN on OS X. It provides easy control of OpenVPN client and/or server connections. It comes as a ready-to-use application with all... Read more
SoftRAID 5.0.4 - High-quality RAID manag...
SoftRAID allows you to create and manage disk arrays to increase performance and reliability. SoftRAID's intuitive interface and powerful feature set makes this utility a must have for any Mac OS X... Read more
Audio Hijack Pro 2.11.3 - Record and enh...
Audio Hijack Pro drastically changes the way you use audio on your computer, giving you the freedom to listen to audio when you want and how you want. Record and enhance any audio with Audio Hijack... Read more

Latest Forum Discussions

See All

Why I Don’t Want to Upgrade to the iPhon...
I’ve been living with my iPhone 4S for the past two years or so, and if I was living in a world where I wasn’t bombarded with new phone announcements and people of the general public caring enough to upgrade constantly, I wouldn’t think my phone... | Read more »
Tictail Review
Tictail Review By Jennifer Allen on September 23rd, 2014 Our Rating: :: CLASSY SHOPPINGiPhone App - Designed for the iPhone, compatible with the iPad Tictail is an attractive and stylish way of looking for some great new clothes... | Read more »
Super Glyph Quest is Bringing More Match...
Super Glyph Quest is Bringing More Match-3 Magics to the App Store Soon Posted by Jessica Fisher on September 23rd, 2014 [ permalink ] Fans of Glyph Quest, by Alex Trowers and Leanne Bayley, | Read more »
Sword King Review
Sword King Review By Jennifer Allen on September 23rd, 2014 Our Rating: :: WEAK, SO WEAKUniversal App - Designed for iPhone and iPad Ever wanted to tap on a screen and assume you’ve killed a monster or two? Probably not, but just... | Read more »
Pangea Software Unveil Bundles and iOS 8...
Pangea Software Unveil Bundles and iOS 8 Updates Posted by Ellis Spice on September 23rd, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Race Team Manager Review
Race Team Manager Review By Jennifer Allen on September 23rd, 2014 Our Rating: :: LIGHT RACINGUniversal App - Designed for iPhone and iPad Want to be in charge of a racing team but not be overwhelmed by tactics and options? Race... | Read more »
Kobojo Works with Creative Minds from Fi...
Kobojo has announced details for their newest game, Zodiac – a 2D persistent online RPG. Kobojo has put together a crack team of developers including composer Hitoshi Sakimoto and scenario writer Kazushige Nojima, whose work includes many of the... | Read more »
PlayHaus Review
PlayHaus Review By Amy Solomon on September 23rd, 2014 Our Rating: iPad Only App - Designed for the iPad PlayHaus is a interesting, stylish app for young children, full of cause-and-effect interactions.   | Read more »
Astropolo Review
Astropolo Review By Amy Solomon on September 23rd, 2014 Our Rating: Universal App - Designed for iPhone and iPad Astropolo is a space-themed children’s app with a great sense of style.   | Read more »
New E*TRADE Update Includes Touch ID and...
New E*TRADE Update Includes Touch ID and Home Screen Widget for iOS 8 Posted by Jessica Fisher on September 23rd, 2014 [ permalink ] | Read more »

Price Scanner via MacPrices.net

Razer DeathAdder Chroma Gaming Mouse Upgraded...
Razer has announced the launch of their new Razer DeathAdder Chroma gaming mouse. Even if you’re not a gamer, the DeathAdder bears considering. I’m a fan of the hard-wired tracking accuracy,... Read more
Check Apple prices on your device with iTracx
MacPrices is proud to offer readers a free iOS app (iPhones, iPads, & iPod touch) and Android app (Google Play and Amazon App Store) called iTracx, which allows you to glance at today’s lowest... Read more
Refurbished 2013 MacBook Pros available for u...
The Apple Store has Apple Certified Refurbished 13″ and 15″ MacBook Pros available starting at $929. Apple’s one-year warranty is standard, and shipping is free: - 13″ 2.5GHz MacBook Pros (4GB RAM/... Read more
New iPhones Score Big in SquareTrade Breakabi...
SquareTrade has announced the iPhone 6 and its larger sibling, iPhone 6 Plus, performed impressively in Breakability testing, and each carries the top Breakability Score in their respective category... Read more
10 Million + First Weekend Sales Set New iPho...
Apple has announced it sold over 10 million new iPhone 6 and iPhone 6 Plus models, a new record, just three days after the launch on September 19. iPhone 6 and iPhone 6 Plus are now available in the... Read more
Betty Crocker Launches New Cookbook for iOS
Betty Crocker, a General Mills brand, an established food industry leader, has announced its free digital cookbook app has been refreshed to make cooking with iPhone, iPad and iPod touch even easier... Read more
Apple restocks some refurbished 2014 MacBook...
The Apple Store has restocked some Apple Certified Refurbished 2014 MacBook Airs, with prices starting at $769. An Apple one-year warranty is included with each MacBook, and shipping is free. These... Read more
13-inch 128GB MacBook Air on sale for $949, s...
B&H Photo has the new 2014 13″ 1.4GHz/128GB MacBook Air on sale for $949.99 including free shipping plus NY tax only. Their price is $50 off MSRP. B&H will also include free copies of... Read more
Apple offering free $25 iTunes Gift Card with...
The Apple Store is offering a free $25 iTunes Gift Card with the purchase of a $99 Apple TV for a limited time. Shipping is free. Read more
Apple refurbished iPod touch available for up...
The Apple Store has Apple Certified Refurbished 5th generation iPod touches available starting at $149. Apple’s one-year warranty is included with each model, and shipping is free. Most colors are... Read more

Jobs Board

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* 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
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
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.