This pushes all of my buttons. It’s got structured documents, Web, parser geekery, writing, engineering, and standards. There’s a bunch of open source prior art, including PyXMLWiki, which I adapted from some fantastic earlier work from Rick Jelliffe.

Sadly, MarkLogic employees aren’t eligible to enter. Get your write-up done by July 15 and sent to balisage-2010-contest at marklogic dot com. The winner will be announced at Balisage and will take home some serious prize winnings, and also will be strongly encouraged (but not required) to give a brief summary (~10 minutes) of their winning entry.

Can’t wait to see what comes out of this. -m

[Two men in a satirical dialog] managed only to demonstrate that the mathematical limit of an infinite sequence of “doubting the certainty with which something doubted is known to be unknowable  when the ’something doubted’ is still a preceding statement ‘unknowability’ of something doubted,” that the limit of this process at infinity can only be equivalent to a statement of absolute certainty, even though phrased ans an infinite series of negations of certainty.

It’s not like the whole book is like this…far from it. But it is chock full of little gems.

-m

(Spanish) First-person singular (yo) present indicative form of omitir (to omit).

(Proto-English) Shortened word form of an error of omission, e.g. in written.

More collected Geek Thoughts at http://geekthoughts.info.

that one would be able to ask a computer any factual question, and have it compute the answer.

Which has proved to be quite distant from reality. Instead

But armed with Mathematica and NKS [A New Kind of Science] I realized there’s another way: explicitly implement methods and models, as algorithms, and explicitly curate all data so that it is immediately computable.

It’s not easy to do this. Every different kind of method and model—and data—has its own special features and character. But with a mixture of Mathematica and NKS automation, and a lot of human experts, I’m happy to say that we’ve gotten a very long way.

I’m still a SearchMonkey guy at heart, so I wonder how much Wofram’s team is familiar with existing Semantic Web research and practice–because at a high level this seems very much like RDF with suitable queries thereupon. If that’s a good characterization, that’s A Good Thing, since practical application has been one of SemWeb’s weak spots.

-m

I’ve always thought there is great power in having both XSLT and XQuery tools at one’s disposal. I’ve seen people tend to polarize into one camp or the other, but in truth there is a lot of common ground, as well as cases where the right technology makes for a much more elegant solution. So learning both is easier than it seems, and more useful than it seems.

If you will be around the conference, take a look at the syllabus. I’m curious to see others’ reactions toward the combined XSLT + XQuery toolset. -m

From there the included 2to3 tool was easy enough to run. (Relatively more difficult was getting 2.6 and 3.0 versions of Python frameworks installed on Mac, but even that wasn’t too bad.) The tool made some moderate changes, and I can run the unit tests, and a few even pass!

The primary remaining problem stems from code where the documentation is a little unclear, and my inexperience is severe. The part of the code in platonicweb.py that reads nasty, grotty HTML via Tidy and produces a clean DOM throws an exception every time. Seems to be a mismatch between String and Byte (encoded string) types, but manifested as a failed XML parse. Sans exception handling, the code looks like:

    page = urllib.request.urlopen(fullurl)
    markup = page.read()
    dom = xml.dom.minidom.parseString(markup)

urlopen() returns a file-like object, but the docs didn’t seem clear on whether it’s like a file opened in byte or string mode. In any case, I’m almost certainly doing it wrong. Suggestions?

-m

Assertion-based schema language. A way to test XML documents. Rule-based validation language. Cool report generator. Good for capturing edge cases.

Same architecture as XSLT. (Schematron specifies, does not perform)

<schema xmlns="http://purl.cclc.org/dsdl/schematron">
  <title>Check sections 12/07</title>
  <pattern id="section-check">
    <rule context="section">
      <assert test="title">This section has no title</assert>
      <report test="p">This section has paragraphs</report>
      ...

Demo. OxygenXML has support. Assert vs. Report – essentially opposites. Assert means “tell me if this if false”. Report means “tell me if this is true”.

“Almost as if Schematron is a harness for XPath testing.”

More examples:

<rule context="note">
  <report test="ancestor::note">A note appears in a note. OK?</report>
</rule>

Binding: Default is XSLT 1, but flexible enough to allow other query langauges via attribute @queryBinding at the top. Many processors allow mix-and-match between XSLT and Schematron. Examples showing just that.

Some tests can be very useful:

test=”every $line in tokenize(., $newline) satisfies string-length($line) le 72″

Q: What if the destination is not a human, but another part of a pipeline? Varies by implementation, but SVRL is standardized as an annex in the ISO spec, part of DSDL.

Use as little or as much as you want, at different times in the document lifecycle. “Schematron is a feather duster that reaches areas other schema languages cannot.” – Rick Jelliffe

As time permits section of the talk:

Other top-level elements: title, pattern, ns, let, p, include, phase, diagnostics.

-m

Now, quite a few standards based on XPath depend on the context node being set to some particular node. This turns out to be easy too, using the path operator: $context/xdmp:value($expr). According to the definition of the XPath path operator, the expression to the right is evaluated with the results of the expression on the left setting the context node.

OK, how about setting the context size and position? More difficult, but one could use a sequence on the left-hand side of the path operator, with the desired $context node in somewhere in the middle. Then last() will return the length of the sequence, and position() will return, well, the position of $context in the sequence. But it’s kind of hacky to manufacture a bunch of temporary nodes, only to throw them away in the next step of the path.

I’m curious if anyone else has done something similar. Comments? -m

Imagine you are writing a smallish widget app, in an environment without a standard library. When you need to sort your widgets, you’d write a simple function with a signature like sort(sequence-of-widgets). That’s great.

Now imagine you find your app to be steadily growing. An accumulation of smaller one-off solutions won’t work anymore, you need a general solution. What you’ll end up with is something like qsort in C, which takes a pointer to a comparator function. By providing different comparators, you can sort anything any way you like, all through only a single sort function. C and C++ have something like this, as do PHP, Python, Java, JavaScript, and even assembly language. XSLT has it, as proven by Dimitre.

XQuery doesn’t. It should, because people are now using it for more than short queries. People are writing programs in it. -m

P. S. Comment please.

More collected Geek Thoughts at http://geekthoughts.info/.

curly apostrophe looks like ?’ – original encoding=_________ mislabeled as __________ .

That sort of thing. Surely somebody has done this arleady, right? -m

I’ve been known to use this as an interview question, and it’s quite a bit harder than it looks. A clever candidate will turn the paper sideways giving themselves more room to write “two lines”, but that’s not the point. This exercise forces one to really think about their qualifications, skills, and experience; one’s “unique selling proposition”.

Writing short, as opposed to rambling on, is notoriously difficult. Someone who can do that with their own CV is off to a good start in my book. -m

P. S. Mark Logic is looking for some high-caliber XML and web folks. Contact me offline if you know anyone looking…