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Schematron and time: complex event processing?

By Rick Jelliffe
November 14, 2009

I have been thinking a little bit about whether Schematron's pattern approach could be applied to complex event processing where the input is a stream of discrete XML documents, for example each one being a reading from a set of...

The Grammar of Schematron

By Rick Jelliffe
September 15, 2009

A lot of Schematron can be implemented directly in a mildly enhanced version of RELAX NG without (I think) explosions, before it all runs out of steam.

Test-Driven Development for standards-makers - Connexions with XML, XSD and Schematron

By Rick Jelliffe
August 23, 2009

Fans of nerdy men with beards will enjoy the InfoQ website. Watching Freeman and Feather's TDD - Ten years later, a few things stuck out relevant to standards-makers and to Schematron.

OASIS CAM versus ISO Schematron - A new technique for Schematron: exemplars

By Rick Jelliffe
August 21, 2009

My normal initial reaction when reading the CAM spec is to huff and puff about borrowing ideas badly. No patterns! No phases! No diagnostics! No roles! No assertion text! And so on. But it is to compare apes and orangutans: the things I consider important are not the things CAM was developed for.

Converting XML Schemas to Schematron (#16): XML Schema Test Suite results for beta 0.5 - The suite smell of success?

By Rick Jelliffe
August 6, 2009

Paul Hermans has kindly set up a process (I believe an XProc pipeline using Calabash and SAXON 9) to test the XML Schema to Schematron converter I have been documenting in this blog over the last few years. Here are some results.

Converting XML Schemas to Schematron (#15): Qname madness

By Rick Jelliffe
August 6, 2009

I have recently being doing some more work on the XML Schema to Schematron converter, and one of the first issues to come up is more proper handling of namespaces.

ODF Plugfest

By Rick Jelliffe
June 16, 2009

I am looking forward to seeing the report from the ODF Plugfest 2009. The Dutch government is doing everyone a great service in organizing this.

Validation using tries and feature sets

By Rick Jelliffe
June 8, 2009

There is another design or implementation option for validation, which is to generate a trie for the document, then to validate that trie. Because our schema languages attempt to validate more than a trie can represent, we also must extract a feature set from our schemas: this is true whether the schema is a grammar-based schema or a Schematron-style schema.

The top three mistakes in Schematron

By Rick Jelliffe
June 8, 2009

After almost a decade of Schematron schemas, here are the three errors I see most often.

Conformance in the floating world

By Rick Jelliffe
May 26, 2009

This article looks at some trends and challenges for document validation. The challenges come in two classes: first, raw capabilities for lifecycle support for standards; second, coping with transitions from technologies defined by implementation to technologies defined by standards with the necessary agility.

Dan's the man!

By Rick Jelliffe
May 22, 2009

Dan Brickley blogs on my current to-ing and fro-ing with the W3C TAG and brings up an RDF angle.

Associating Schematron with documents in editors

By Rick Jelliffe
May 22, 2009

An effort at ISO SC34 WG1 to try to get an agreed on way to associate documents with schemas. Plus some recent editors that support ISO Schematron, and a link to a good video introduction to Schematron for developers.

Thinking about optimizing a custom Schematron validator

By Rick Jelliffe
May 20, 2009

I'd love readers to submit in programmer-friendly terms some of the new ideas and possibilities on optimizing XPath. In particular, I am interested in optimizations relevant to Schematron.

The Assertions in HTML 5

By Rick Jelliffe
May 19, 2009

Lets look at the assertions in draft of HTML 5: The Markup Language which collects constraints about the markup: the kinds of things that are susceptible for schema testing.

Schematron on the Browser: JavaScript, CSS3 selectors, JQuery, Regex, JSON

By Rick Jelliffe
May 14, 2009

Schematron run from inside JavaScript on the web-browser, editing structured documents/data trascribed to HTML. Click "validate" and a box comes up with a list of the validation problems; click on of those and the corresponding text or element is background-highlighted. Very slick. 300 lines of code only.

Converting XML Schemas to Schematron (#14): beta available

By Rick Jelliffe
March 9, 2009

The beta release of my open source XML Schema validator is available now, from Schematron.com.

Running Schematron: the evolution of the pipeline

By Rick Jelliffe
February 24, 2009

Here is a test: when you hear the terms "layering" and "pipelines" are they abstract gibberish which bear no hard relation to the way that you develop? This post looks at how Schematron and parts of DSDL can be implemented in a pipeline. In order to explain the design of the latest release of Schematron, I thought it would be useful to show how the Schematron design has changed over the last decade to involve mulitple stages.

Running Schematron: bat/shell, Ant, XProc

By Rick Jelliffe
February 20, 2009

I thought I would write a little blog item about running Schematron in batch environments. Here are examples for command-lines, Ant and XProc.

Schematron 2009 released

By Rick Jelliffe
February 20, 2009

The latest and greatest release of my (our) open source ISO Schematron validator is out now, available at Schematron.com. Schematron is a validation language for making assertions about the presence or absence of XPath patterns in XML documents; it is the most powerful of any standard schema language for validation.

Is Schematron a rules language?

By Rick Jelliffe
January 23, 2009

Schematron's assertions are held in rule elements, but is Schematron a rules language at all?

RDFa: not the flopperooni one would expect?

By Rick Jelliffe
January 16, 2009

The W3C's RDF effort has, in the main, been an enormous flop. Now it seems that RDF/Semantic Web is in a much more solid position than before, and if it is positioned now as a technology that fits in and augments existing systems, it has a chance of working. RDFa, RDF Schema in Schematron, GRDDL

Analysis 2009: Syndication forms the backbone of the Writable Web

By Kurt Cagle
January 6, 2009

The syndication model has long been a major facet of the way that the web works, but for the most part its been a largely single direction notification mechanism - you publish content, this updates a syndication queue, then...

Converting XML Schemas to Schematron (#13): Identify constraints

By Rick Jelliffe
December 12, 2008

This article sketches out how to implement the same functionality as XSD's integrity constraints in Schematron.

Converting Schematron to XML Schemas, part 2

By Rick Jelliffe
December 3, 2008

I have not written anything about converting Schematron schemas to XML Schemas in the 12 months since the last little article. So here is another approach for schemas that were not written to be XSD-conversion friendly: it is just brute force and ignorance (BFI) pattern matching.

Using Schematron to declare and report implementation limitations

By Rick Jelliffe
November 25, 2008

Implementation schemas are used to test documents that they only contain structures or values that can be accepted by a particular implementation of a standard schema.

A sketch on recasting XBRL in Schematron

By Rick Jelliffe
November 24, 2008

In the next few years a lot of people will be generating XBRL documents, in particular for financial filings to regulators. And a few years later a lot of people will be figuring out what to do with all that data too..I decided to take a look at whether XBRL could, keeping the same instance syntax and concepts, have a schema language transplant so that Schematron was used instead of XSD....

Schemas: stereotypes, archetypes or prototypes?

By Rick Jelliffe
November 17, 2008

The problem with schemas is this: sometimes we need prototypes, sometimes we need archetypes, sometimes we need stereotypes, but transitioning between them is not trivial in any schema language, which may be optimised for particular cases.

Validating Code Lists with Schematron

By Rick Jelliffe
November 13, 2008

How happy the man whose documents are clearly divided into variant and invariant: data versus schemas. But in the real world, often there are data values or structures which have fixed choices, but not completely fixed: a twilight zone. Here is a summary of various ways of validating lists using Schematron, including how to validate data values that are drawn from multiple external glossaries.

Fake real-time blog from SC34 meeting: including audio of proposed Schematron revision

By Rick Jelliffe
September 30, 2008

I presented by podcast to WG1 (which is the working group on schema languages) my suggested update to ISO Schematron.

A standards-based expert system for detecting structures and annotating XML-in-ZIP documents

By Rick Jelliffe
August 19, 2008

One of the projects I have been working on recently has been a proof-of-concept system to allow a rules-base approach to automatically classifying and annotating XML-in-ZIP documents. The approach we have taken is to use Schematron, using the report elements rather than the assert elements.

Localizing XSLT error messages for Schematron

By Rick Jelliffe
August 14, 2008

I was surprised to read a review of Schematron and other schema languages which cited the lack of localization as an important reason to not use it, so the next release of the skeleton has localized messages. Here is the approach I took to localize the XSLT.

The challenge of validating XML-in-ZIP file in place: how to do it with Schematron

By Rick Jelliffe
August 11, 2008

Thoughts on Schematron headers for processing ODF and OOXML, with a C# URL Resolver that handles ZIP files like some Java resolvers. The new XML-in-ZIP documents present a new challenge: constraints that formerly would have been kept in a single document are now split into multiple documents. When the basic information is kept in a single XML file, validation is reasonably straightforward.The current range of schema tools support these kinds of intra-document invariants quite well. But no document is an island, so Schematron also supports a range of intra-document constraints, but it may be time to enhance it to support the XML-in-ZIP issues better.