peteg's blog 2008-01-17-StaticLinkingBlues.autumn

Rounding up some press.

I was interviewed for the women's newspaper, Phunữ. Left-to-right in the photo: DRD Director Chị Yến, my counterpart Triêu and me, and the MacBook in the foreground, of course. We're seated in the corner of the DRD office. I asked the journalist to publish my email address but sadly she did not.

More press coverage at Tuổi Trẻ and Daily.com.vn. I guess this means my AYAD project was a success.

Website launch.

We're famous, we've got the top hit on Google Việt Nam for "DRD", and on the front page for Google.com. The launch went fairly well, with demonstrations of the "zoom" layout and the JAWS screen reader, and good attendence by the press. There were some good questions and I was exhausted by the end of it.

DRD Website Mới live.

Partly by accident, partly by design, the new DRD website is now live. It has some remaining rough edges which I'll be ironing out this week and next. We'll have a launch press conference this Sunday, June 29. Any and all feedback is very welcome.

Project blah blah.

I've been reading a lot of accessibility articles. Most are (at best) unscientific. If you can cope with the outmoded HTML advice, the best is Joe Clark's Building Accessible Websites. I feel his treatment of colour blindness is ... excessive, in a good way.

Finally someone has cooked up a good explanation of how to stuff Flash into a webpage, and why <embed> lurches forever onward. It has convinced me that if one decides to be evil and use Flash, one must necessarily also use JavaScript.

My goal of actually putting the XML part of XHTML to work by validating the comments and general content coming into HOPE with HaXml is mostly working, modulo some bugs here and there. Break it here: http://210.245.124.74/~drdviet/hope/ (soon to become the main DRD site, I hope.)

The I'm-in-a-hurry guide to accessibility.

I've been warmly surprised by some of the general-topics things I've found on the net recently; either Google's search results are tending away from waffle or I am becoming very adept at closing tabs and flushing the short-term memory buffer. Dive into Accessibility is straightfoward and the tips mostly directly applicable. Unfortunately it has dated a bit; I shudder to think that there are too many HTML 4 websites out there that people now want to make accessible...

I slightly quibble with his advice on access keys (Day 15, p32 of the PDF), where he suggests that a stroke survivor may make use of them. I expect there are many people who struggle to make key chords, especially those having the use of just one hand.

To `accesskey` or not to `accesskey`...

An accesskey is another of the W3's ways of muddling concerns; when you type something into a web browser, what does it mean? Does the browser get the keystroke or the page, or the form, and which form are we talking about anyway... It seems the prevailing wisdom is not to use accesskeys as the implementations are broken; in a nutshell, this misfeature is not compositional, a feature shared with all the very worst XHTML ideas.

Back in the real world we're stuck between doing something "many users will be familiar with" (yeah, I remember that) and leaving things alone. I've decided to follow the BBC's ambivalent lead here.

Lazy CSV Parsing in Haskell.

One of the fun bits about this project is the text munging that comes with it. The regexp libraries for Haskell have super-sophisticated do-what-I-think-you-mean interfaces and not enough (simple) use-cases in the docs. Couple that with my concerns about Unicode support and I'm stuck doing it the very old fashioned way.

OK, enough editorialising; I've written a mostly-{RFC 4810, Haskell 98}-compliant lazy CSV parser that appears to work OK on reasonable-sized inputs. Existing solutions use Parsec, whose return type seems to guarantee that more-or-less the entire output must reside in memory at some point. This might be OK for small files, but the 6Mb of Unicode data I need to import consumes a ridiculous amount of memory, even with GHC's optimiser going full-bore.

You can find it here. The licence is BSD. Couple it with the appropriate utf8-string for your GHC and it works well on UTF-8-encoded files.

Now, to track down a nasty memory leak somewhere in the database code... the profiler tells me SYSTEM is hanging onto some stuff, but not what SYSTEM actually is. Err, what did Fergus say again?

Simplifying the XHTML DTD for fun and profit.

For the usual reasons it seemed best to use FCKeditor as an input widget for HOPE. I had hoped to provide some kind of hacker-friendly markup but time is short and convincing FCKeditor to generate it would probably require some heart surgery. So XHTML everywhere it is.

Clearly this path should lead to paranoia; we can't allow users to submit arbitary strings, or even arbitary XHTML. My heavyweight solution is to validate such submissions against a stripped-down XHTML DTD using HaXml. So far I've removed forms, scripts and restricted the attributes of <a> to just href. I wish the DTD was readable; it is merely an algebraic data type afterall.

Combined with some thorough string-escaping for the other inputs and a tendency to cop-out (crash) on anything that doesn't completely conform to expectations, I think we will be all right.

You can try your hand here. Any and all feedback is much appreciated.

In related news I've uploaded my FCKeditor "server-side integration" Haskell library to Hackage. Find that here.

People like their webpages the way they like their streets.

I went to visit Marc today, at the Prince of Wales Hospital, and we got around to talking about design. Roughly speaking, it seems to me that people tend to like their webpages the same way they like their streets. In Australia, and perhaps the West in general, we want order, clearly marked lanes, pedestrian crossings, accessibility in the form of kerb cuts and beeping and flashing attention-getting devices. The footpaths are clear of stalls and coffee merchants. Conversely Asia seems to prefer craziness, where finding things is difficult but what you do find is sometimes more valuable than what you set out for. As Marc observed, one uses fifty fonts to show that one is more prosperous than the guys who only used forty-nine, and damn that street food (mystery meat) is tasty.

I'm going to have to face up to the tension between Vietnamese website aesthetics and aspirations to accessibility rather soon.

HOPE in a host(ile) environment.

I finally managed to get HOPE to statically link. Björn does this against MySQL, so the infrastructure was there, but Debian's PostgreSQL binary packages are built with Kerberos support, and apparently libkrb5-dev no longer supports static linking. I rebuilt them with all that switched off (thanks Debian, that was pretty easy), and now the linker seems happy. The hazards of binary packaging...

So, why bother with this at all? Well, the company that will host DRD's new website apparently doesn't have GMP installed. This threw me a bit; I expected it to be missing all sorts of stuff, but GMP? I have been using GHC for too long it seems. Sure, I could try to arrange for the shared library to be present, or statically link just GMP in, but it seemed better to insulate HOPE from any other changes in the hostile environment with too much overkill, rather than not enough.

Next up: what happens when /etc/hosts is MIA? How do I talk to the database server? I begin to understand why everyone sticks to PHP and MySQL, and why Ruby on Rails's convention-based approach is such a big deal.