Technical Ramblings

Over the past couple months, I’ve been importing a large chunk of data, largely from Zami, into the Open Guide to Boston. Tonight, the guide crossed the 1000 place mark, and I decided that showing everything on one map was no longer making much sense.

The result? Boston Mashup – pick the categories you want, and they’ll be dropped onto a map, with a different color for each type of marker (up to 7 – I don’t have that many colored markers yet).

I’ve still got more I want to do with it, but it works, and works pretty well: much better than I expected it to. Thanks to perigrin for helping me work around my Perl ineptitude and solve the problems I needed to.

Not really much to say about it other than that: try it out, let me know what you think. I’m happy with it, at least as a starting point, so I think that’s probably a good sign.

Something I was previously unaware of:

The reason for the two different variations of “and” and “or” operators is that they operate at different precedences.

PHP’s && vs. and have different precedence? Who thought this was a smart idea? What end or purpose could it possibly serve?

Yet another one of the things that just makes me smack my head. It does explain a few things — why I couldn’t do variable setting as I might in Perl, a la:

$var = $test || $default;

In this case, the test occurs first, setting $var = 1; Had I used:

$var = $test or $default;

All would have been fine.

How can someone think this is sane?

Apparently the anxious type, Greg Williams has thrown together an RDF Query implementation in Perl, with support for the new SPARQL draft as of yesterday.

The library also offers ORDER BY support, something that I’m sure Greg is happy to have for his MT-Redland. Ordering things by date for me is something that I’ve sidestepped, but I’m not looking forward to when I actually have to deal with it.

The code uses Parse::RecDescent to generate a query based only on the SPARQL grammar. Greg mentions that it is slow: most of the time is actually in generating the Query from the Grammar.

If only I was still a Perl hacker… sadly, I’m not, so I suppose I’ll just have to start working on my C in order to help get Redland working with the new draft. (Dave estimates that it will take him about 1.5 months to catch up to the most recent WD of SPARQL.) I’d really love to just be able to use the tools I’ve already written in Python, rather than switching to Perl, or even another backend than Redland. It has worked so well for me so far.

Still, this is the first SPARQL implementation using the new Draft that I’m aware of, even if it is mostly just a hack job, so I think that it’s pretty cool, and my props are out to Greg for his work on it!