WWDC 2008

The time is upon us once again — WWDC time!

As I have the past few years, I’ll be in San Francisco all week, staying at the Hotel Kabuki in Japantown.

And of course, I’ll be around the conference all week — especially in the labs. Come by and say hi, and I’ll be happy to help with any questions you have!

CocoaHeads Silicon Valley at Apple on Thursday, May 15, 2008

The next CocoaHeads Silicon Valley meeting will be on Thursday, May 15, 2008 — that’s tonight! — at 7:30 in the Garage 1 meeting room at Infinite Loop 4 on Apple’s main campus. That’s inside and upstairs at Apple’s Infinite Loop campus in Cupertino. See the web site for directions.

This month’s main presentation is on the Best of Both Worlds — an introduction to Cocoa development by Scott Stevenson.

This talk is a combination of an introduction to Cocoa, as well as a series of advanced tips and tricks that even relatively experienced Mac programmers may not know about.

The idea here is that we want to give all of the people who are new to Mac and iPhone development a chance to get started, but we also want to do something special for our advanced programmers. So rather than choosing one, we’re just going to go ahead and do both.

Joel Norvell will also be presenting on how to edit PDF forms using Cocoa — he’s done a lot of work with PDFKit and Cocoa, and I’m looking forward to learning from him.

Thanks a ton to Scott Stevenson, Steve Zyszkiewicz, Michael Jurewitz and Joar Wingfors for organizing!

In general, at a CocoaHeads meeting we do some introductions, have a presentation including Q&A time with the presenter, and then have an open Q&A and demo-your-cool-app period. After the meeting there’s more independent mingling and discussion until it’s time to go at 9:30. Often a subset of the meeting moves to BJ’s Brewhouse in Cupertino, which is right in front of the Apple Infinite Loop campus on De Anza Boulevard.

Why is Twitter not just Jabber?

Twitter is a way to post a short message to a wide group of subscribers, and to receive messages posted by a wide group of subscribers.

That’s instant messaging. There’s already a standard protocol for it: Jabber (XMPP).

Why not just use it? Why invent a new protocol?!

Actually, Twitter already does have experimental XMPP access to the full timeline — rather than to individual timelines, or to your friends’ timelines — and you can use it to build things like TweetMaps and TweetClouds and Quotably and…

But Twitter should really be built entirely around XMPP. It shouldn’t be a web app at all, though it could certainly have a web front-end. In case you doubt me, here’s an example Twitter-like service implemented by Process One atop the ejabberd XMPP application server.

Build LLVM and clang!

I’ve talked about the LLVM Compiler Infrastructure in the past, but what I haven’t talked about yet is just how easy and quickly you can build it on your own Mac running Leopard! This is a great way to get into hacking on compiler lexical analyzers and parsers, code generators, optimizers, and so on.

What’s more, you can build both LLVM and the new C front-end clang very easily and in five to ten minutes.

First, create a work area to check them out into, wherever you normally create your projects.

[~]% cd /Projects
[/Projects]% mkdir LLVM
[/Projects]% cd LLVM
[/Projects/LLVM]%

Then check out LLVM itself and clang from the LLVM Subversion repository.

[/Projects/LLVM]% svn checkout http://llvm.org/svn/llvm-project/llvm/trunk llvm
[/Projects/LLVM]% cd llvm/tools
[/Projects/LLVM/llvm/tools]% svn checkout http://llvm.org/svn/llvm-project/cfe/trunk clang
[/Projects/LLVM/llvm/tools]% cd ../..
[/Projects/LLVM]%

Then edit the PARALLEL_DIRS definition in llvm/tools/Makefile to tell it about clang. Just add clang onto the end, like this:

PARALLEL_DIRS := llvm-config  \
                 opt llvm-as llvm-dis \
                 llc llvm-ranlib llvm-ar llvm-nm \
                 llvm-ld llvm-prof llvm-link \
                 lli gccas gccld llvm-extract llvm-db \
                 bugpoint llvm-bcanalyzer llvm-stub llvmc2 \
                 clang

Now create a directory to build into, next to your llvm directory, and change into it.

[/Projects/LLVM]% mkdir build
[/Projects/LLVM]% cd build
[/Projects/LLVM/build]%

This is where you’ll actually run configure. This will ensure your source tree isn’t polluted with build products, and that everything stays self-contained while you hack.

[/Projects/LLVM/build]% ../llvm/configure --enable-targets=host-only
# lots of logging
[/Projects/LLVM/build]%

You’ll note that above I passed an argument to configure. This ensures that LLVM is only built to target the architecture I’m running on, to speed up the build process; this is generally fine for simple front-end development.

Now, to build LLVM as well as clang all I have to do is invoke make. LLVM is set up to correctly do parallel builds, so I’ll pass the number of CPUs I have in my machine via make -j 4.

[/Projects/LLVM/build]% make -j 4
# lots of logging
[/Projects/LLVM/build]%

That’s it! LLVM is now (hopefully) successfully built. All of the pieces are in the build directory under Debug/bin and Debug/lib and so on; see the LLVM web site for details about what the various components are.

Copyright canonical form

One thing that’s nagged at me lately has been the series of applications I’ve seen lately with copyright statements that appear to be from the Bizarro universe. I don’t mean that they have weird license restrictions; rather, they have a copyright statement in their standard About panel that’s formatted strangely. It’s a minor pet peeve to be sure, but it’s a simple thing to get right and getting it wrong looks silly.

Note that the following is not legal advice on asserting or protecting your copyright — you’ll have to go to a lawyer for that — it’s just a suggestion on how to concisely format your statement that your work is covered under copyright.

In a Cocoa application, the standard About panel will show the copyright statement specified under the NSHumanReadableCopyright of its Info.plist file. This should generally be of the form

> Copyright © «YEARS» «HOLDERS». All rights reserved.

where «YEARS» represents the individual year, set of years, or range of years during which the application was authored and «HOLDERS» represent the authors of the application.

Thus if I were to start writing an application in 2007 and finish it in 2008, I would put

> Copyright © 2007–2008 Chris Hanson. All rights reserved.

in the NSHumanReadableCopyright key of its Info.plist file. (Yes, that’s an en-dash between the years, option-hyphen gets you one.) It wouldn’t have the year at the end, or random commas after things, or random abbreviations. Just one simple statement.

Someday I’ll figure out how to add

> Copyright © 2002–2008 Chris Hanson. All rights reserved.

to the bottom of my weblog, too. Hopefully in such a way that I can actually update it easily when the year rolls over…

CocoaHeads Silicon Valley at Apple on Thursday, Apple 17, 2008

The next CocoaHeads Silicon Valley meeting will be on Thursday, April 17, 2008 — that’s tonight! — at 7:30 in the De Anza 3 auditorium at Apple. That’s just inside the south side of De Anza 3, right across Mariani Avenue from Apple’s Infinite Loop campus in Cupertino. See the web site for directions.

This month’s presentation is all about designing and implementing your human interface. User experience and human interface design are critical for Mac OS X software to get right. To that end, there’s even going to be a UI makeover as Scott describes in his post on the meeting!

Thanks a ton to Scott Stevenson, Steve Zyszkiewicz, Michael Jurewitz and Joar Wingfors for organizing!

In general, at a CocoaHeads meeting we do some introductions, have a presentation including Q&A time with the presenter, and then have an open Q&A and demo-your-cool-app period. After the meeting there’s more independent mingling and discussion until it’s time to go at 9:30. Often a subset of the meeting moves to BJ’s Brewhouse in Cupertino, which is right in front of the Apple Infinite Loop campus on De Anza Boulevard.