(also check my previous post on the subject.)

This one’s different in that the screens aren’t identical; there’s an e-paper display on the left, and a LCD on the right. Both are touch-enabled.

Compare with this image from the tablet proposal by Mario Amaya and myself (posted August 10th, 2009):

Fun! But I like our hinge better…

Then we drove southward to San Antonio, stopping off in New Braunfels along the way. The latter is a German immigrant town, and on our visit to the local museum we were tipped off to a Gartenkonzert scheduled at the Beethoven Männerchor in San Antonio, a local Gesangsverein (singing society). It was interesting though somewhat surreal –  German beer and specialties and all the old music I vaguely remember from my childhood.

After an interesting day in downtown San Antonio the heat drove us northwards to the small town of Fredericksburg, also built by German immigrants, where we’ve now stayed a couple of days. The weather reports on our originally planned route were extremely discouraging, so we’re now planning to return to Austin tomorrow where we’ll decide on where to go.

I can report that Dallas is a maze of straight-ahead multi-lane freeways, all alike, and it’s all flat. Every place looks quite like every other place, and it’s quite confusing to someone who grew up in the Brazilian highlands. I’m really glad that I rented a car with GPS, and that GPS is gradually getting better – the voice generation part still deserves upgrades, however.

That said, we visited the Dallas Arboretum, which is quite impressive, and the JFK Sixth Floor Museum on Elm Street, as well as the nearby Holocaust Museum; small but chilling. Also, of course, the requisite shopping malls and grocery stores. Yesterday we had an excellent time visiting friends in Denton.

Today we drove down to Austin, where we plan to stay a couple of days. After that, the idea is to drive clockwise along the Southern border, then North in the direction of Taos and the New Mexico Canyons, stopping off at Carlsbad Caverns along the way.

As usual, my hope is to get some work done in the evening. Stay tuned.

As usual, most of the juicy details are under NDA, and I try to be careful with that. Some details about Xcode 4 and LLDB have been published, others have been leaked, and this is indeed the parts I liked most; and I don’t doubt more will be made public Real Soon Now.

I can say some general things about the sessions. While there were relatively few Mac OS X-only sessions – Damien Sorresso’s excellent launchd talk was the one I found most enlightening – to my surprise, there were many sessions that applied both to iPhone OS/iOS 4 and to the Mac. I did audit some non-Mac sessions and most of them were informative and well-presented, and I find myself quite interested in doing an iPad app.

While over 2/3rds of the developers present, supposedly, were doing only iPhone/iPad development and were new to that platform, quite a lot of Mac old-timers were present and I had great fun meeting most of them. I was also gratified to, again, being told several dozen times that someone likes and is using my RBSplitView framework.

As usual, I found San Francisco is a great place to visit – and to eat! Special thanks to Russell of the San Francisco Apple Store for helping me buy my iPad and a brace of accessories, and to all of you – you know who you are – who helped me commemorate my birthday.

Update: fixed. Again, sorry about the delay.

I was told that over 60% of the developers this year were newbies both to WWDC and to developing for Apple. This seemed, even, a low estimate; I did meet friends from years past, some of them real old-timers, but there weren’t as many as I’d expected – and almost none of the people I didn’t know, that I talked with, were doing anything on the Mac, although some said they’d try to do so sometime in the future.

Indeed, the Mac OS was conspicuous by its almost total absence in the session list, and it was mentioned only offhandedly by Steve Jobs during the keynote – only once, I think. Another, more unexpected, absence from the keynote was the iPad: this, too, was mentioned mainly regarding sales figures, and the rest of the keynote was all about the iPhone 4 and the newly christened iOS 4.

On consideration, however, it makes sense not to talk about the iPad in the keynote: Jobs is notorious for presenting exactly what he wants the press to publish, and distracting them with too many topics is counterproductive. The iPad has had its presentation a few months ago and is selling so well that they’re probably scared that more people will want one; the factories are at max, and cases and other accessories are back-ordered for days or weeks.

Also, an upgrade for the iPad might be a little premature at this point. Any new version would raise protests from those zillions of people that just bought one; the Flash RAM industry is barely keeping up; a faster CPU would need to be dual-core. Regarding the new fancy Retina screen technology, an iPad screen at about 300 dpi would be 2400 by 1800 pixels! I don’t think any mobile video chip can handle that today. iOS 4 is about the only upgrade that’s reasonable to expect to come out quickly.

The iPhone 4 looks good indeed. I don’t need a cellphone myself but the dual cameras and other goodies are tempting; I find myself wishing that Apple would go into digital cameras again. Still, to me, the real star of this WWDC is Xcode 4, the existence of which was also released to the public today; it’s a major step forward, and – as I said several times in the past – many of its features seem to have been enabled by LLVM and its various side projects. One of them, the lldb debugger, is the one I’m particularly interested in; I never liked gdb much.

Many people asked me if I, too, am afraid that Apple will drop the Mac and Mac OS X entirely in the future. Well, I certainly am not! After all, what else would you use to develop for iOS? Xcode 4, for one, seems positively need a 27″ screen for best use – I’m glad I bought a 27″ iMac not too long ago. While the iOS devices might eventually be the tool of choice for consumers to do most of what they on laptops today, laptops will still be useful, and powerful desktops will always be necessary for anything that needs more CPU or graphics power. That said, I can see the laptop line compressing to, say, two models next year, and the Mac Pro going away entirely, or at least replaced by a model seriously more powerful than the high-end iMac.

To close for today, it is safe to say that – without violating any NDA in the process – is that, at least during the next 4 days, whenever any demo hits a glitch, the presenter will ask the audience to turn off its WiFi devices. I saw it happen already, in fact.

It’s got lots of pockets and zippers, and the main pocket is almost big enough for a MacBook Air. That said, it’s not specific for the iPad, and I’ve already thought about putting in some extra padding in the bottom. But the upscale larger bags are all on back-order.

OK, now for the WWDC tips for newbies. I recommend also (or first) reading the tips from John Martellaro, Brent Simmons, Marco Arment and Peter Hosey – not necessarily in that order. There’s also Apple’s official FAQ.

1. Come in a day early, two or three if you’re from outside the US. It’ll give you some time to get over the jetlag, explore the area around Moscone Center, and meet some people early.
2. Pick up your badge on Sunday in the afternoon. Don’t come in on Sunday morning; although registration opens at 9:00AM, that’s when I will be registering, and I don’t want to stand in line…
3. Take care of your badge. That’s important; if you lose it, there’s no replacement unless you pay again for the entire conference. You may be able to wheedle some Apple employee to give you his badge if your name is Steve Jobs, but otherwise, it’s a huge hassle. What I always do is to bring some small cable ties. Cole Hardware on 4th Street carry them, just a block from Moscone. The trick is to fasten two ties to the badge in a way that locks it to the neckstrap, and I leave the two tails sticking out, one to a side, which keeps the !@#$% thing from flipping over (which it otherwise will do constantly).
4. Unless you’re a legend in your own time, you’ll notice people constantly sidling up to you and stoop to squint at your badge – that’s why it’s important to keep it from flipping over. Even if you go up to someone you’ve talked to a dozen times before, they’ll do that, so don’t be offended; many geeks look alike, and geeks aren’t good at face recognition, anyway. So my tip is to make a special T-shirt for the conference. As long as it’s not too blatantly commercial and/or mentions some direct competitor, they’ll allow it – I recall one of the last WWDCs held in San José, where someone onstage at the keynote mentioned “Brand X” and the next day, all Microsoft employees showed up in “Brand X” T-shirts. Anyway, I have my shirts done at Zazzle, and I use their microfiber shirt; it’s not cheap, but it’s light enough for tropical climates, washes easily on trips, and the colors keep vivid for over a year, even if you use them almost daily.
5. Network. Don’t be shy – almost everybody at WWDC is. Well, you’ll notice the exceptions immediately, anyway. If you’re in a boring session, either walk out and find a better one, or sit down at one of the corridor tables and talk to people there.
6. The WWDC lunch wasn’t too bad in the San José days but has gone downhill steadily since then. Even so, the lunch is also an excellent networking opportunity; don’t waste it. Find some marginally acceptable liquids and solids and sit down at a table, and talk to people. Unless you really need to have that particular meeting right there, avoid going with your old clique.
7. Parties. Well, you should go to at least one – I’m going to sfMacIndie on Sunday (which falls on my birthday, ahem ). However, YMMV, as they say here; most parties are too loud and crowded, unless you enjoy that sort of thing. If you go, keep your badge on and/or wear that T-shirt. There are partial lists of more parties; just google for wwdc 2010 party list. The same goes for the beer bash on Thursday evening; last year the food there was actually good, but the lines were long, and the music was loud and not to my taste.
8. Bring a laptop and the extension cord for the charger; there are lots of outlets, but not always within reach. Bring a travel surge protector or at least an outlet splitter, so you can ask someone to share an outlet if none is free. Pack a long ethernet cable just in case.
9. Many fellow developers will be glad to talk to you, but won’t take kindly to in-person bug reports; more efficient to send an email. If you have a bug report for any of my products, please do email. However, if you have questions about my source code, we can set up a meeting.

That’s about what occurs to me now; be sure to read the other tip pages, though.

Let’s hope Uncle Steve has a nice present for me; I just came from the local Apple Store, where they don’t have any iPads in stock.

I’m rather overloaded at the moment, moving out of my apartment only a few days before going off to WWDC, and I’ve got an iPad app prototype to work on, too; but I’ll definitely look into this as soon as possible. I think that most of the infrastructure, in fact, is already in place inside Klicko.

I did download the Universal Back Button App, but didn’t have time to check out how it works; at any rate, it seems to be quite different in implementation.

On Macs we have a long-standing culture of apps working together.

…

On the iPad (and iPhone) we can sort-of do the same thing. We don’t have AppleScript or Apple events, but we do have the URL scheme thing for inter-application communication. It’s technically possible to do some of these same things.

But we don’t have an easy way to get back to the calling app.

…

What if the calling app added, as a parameter to the URL, a URL to call when the task is completed?

This way the helper app (NetNewsWire in this case) would know, once the task is complete, how to get the user back to their place in the calling app (Twitterrific in this case).

I was thinking about the same issue, coincidentally, and one idea which occurred to me is to use the equivalent of the http referrer URL (often misspelled as “referer” for historical reasons).

For  a standard http request the referrer is the URL of the document containing the clicked link, so you can get back to that document by clicking on your browser’s “back” button. Now, this isn’t really contained in the URL itself – rather, the browser appends this as one of the fields in the http request headers – but the analogy is interesting.

For this to work locally between applications, the referrer URL would need to be set into the URL targeted at the called application. And indeed, there is a -[NSURL setResourceValue:forKey:error:] method that, in theory could add any key/value pair to the URL. (Currently only the “scheme” property seems to be available, though.)

Update: Mike Abdullah points out in the comments that, in practice, this method applies properties to the file a file URL points at, not to the URL itself. Drat.

On the receiving side, the “referrer” value would have to be pulled out from the NSAppleEventDescriptor that the application gets with the ‘GURL’ event.

All this needs filing enhancement requests and Apple would have to do the required twiddling inside their code base – or rather, bases, as this would be useful to have both on the iPhone/iPad and the Mac side. It would take a long time, if it’s done at all.

The alternative would be to developers to, informally, establish a convention for incorporating this into the URL itself. So we’d have something like:
calledscheme:///the/url/parameters&?REF=callingscheme://some/url/to/return

Probably the second part would have to be suitable encoded/escaped, too. Maybe this would be a good topic for discussion at WWDC?