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I use it a lot and, no later than this afternoon, came on a new opportunity to use it to add unit tests to a function that I needed to debug for the Owark project. Following ideas to develop a web service to create page archivesI was writing vtd XSLT transformation that analyses Heritrix crawl logs to determine what needs to be packaged into the archives and one of the touchy functions is to create user friendly local names that remains unique within the exerckce of an archive.
To do so, I have used log. La notion de cloud computing est une question de point de vue: Pourquoi un petit stratus? Ne vous laissez pas tromper par les chiffres: Pourquoi ne pas proposer de regrouper ces montants en une facture mensuelle unique?
Coming straight from the XML infoset, nodes are rather concrete, and you can still smell the electronic ink of their tags… Each node is unique and lives in its own context: They may look identical and have the same content, they are still two different nodes like identical twins are different persons.
Their value, by contrast, is the same value: The fact that values are shared between the places where they are used is very common among programming languages. In Fortran IV, the first programming I have ever used, these values were not well write protected you could manage to assign the value 6 to 5leading to dreadful bugs and I remember that I had taken the challenge xlm write a program that was using values as variables!
Sequences are really special.
They are not considered as a model item and are just a kind of invisible bag to package items together and are useful because you can store them in variables and use them as parameters. They disappear by themselves when they pack only one item and their is no way to differentiate a sequence of one item from the item itself. XDM has invented a perfectly biodegradable bag! Assuming that your input document is the one mentioned above, the equivalent of an XSLT 1.
Maps being a brand new type of item, the choice is open: Still before discovering Fortran IV, I did study mathematics and geometry and I was fascinated by the dual approach for solving problem in geometry using either Euclidean vectors or points and segments.
Télécharger xslt PDF |
In the current proposal, a map is like a vector: On the contrary, a node is like a segment. In geometry, vectors and segments are both useful and complementary. Both are useful data structures, why should they be treated so differently?
I understand that there are at least to use cases for maps: These two use cases look very different to me. Why should lightweight structures be limited to maps corirg why should maps always been lightweight? In geometry the processes by which you create a vector from a segment or a segment from a vector by pinning one of its extremities are well known.
This is not so uncommon for programmers: A handy feature of sequences and maps as currently proposed is that they can include exercicf. When a map entry is a node, the node keeps its context within a document and its parent remains its parent in this document. How can you do that if you want to also represent the reverse relation between the node and the map entry in which it has been added?
One option could be to define a mechanism similar exercide symbolic links on Linux: Now, would that be a practical exercixe to do? What about adding a map with a node as a new entry on another map? I hope that these musings can be helpful, but I should probably stick to my role of XDM user rather than giving suggestions!
I think xmo we need both lightweight map structures and the full set of XPath axis on maps de-serialized from JSON objects. Having only lightweight map structures means that users and probably other specs and dfd will have to continue to define custom mappings between JSON and XML to perform serious work.
This issue has been submitted to the W3C as Michael Kay has recently proposed to add maps as a fourth item type derived from functions.
The main motivation xtd this addition is to support JSON objects that can be considered as a subset of maps items. However, in the current proposal map items are treated very differently from XML nodes and this has deep practical consequences. When the same structure is expressed in Cotrig and parsed into an XDM map, XPath axes can no longer be used their purpose is to traverse documents, ie nodes and we need to use map functions: Another important difference is that node items are the only ones that have a context or an identity.
When I write foo: This difference is important because that means that XPath axes as we know them for nodes could never be implemented on maps: I think that this is important for XSLT and XQuery users to corrit able to traverse maps like they traverse XML fragments with the same level of flexibility and syntaxes that are kept as close as possible.
And yes, that means being able to apply templates over maps and be able to update maps using XQuery update…. In a longer term we can hope that XForms will abandon this hack to rely on XDM maps XForms relies a lot on the notions of nodes and axes.
XForms binds controls to instance nodes and the semantics of such bindings would be quite different to be applied to XDM map entries as currently proposed. Both XPL and XProc have features to loop over document fragments and choose actions depending on the results of XPath expressions and again the semantics of these features would be affected if they had to support XDM maps as currently proposed.
Schematron could be a nice answer to the issue of validating JSON objects. Schematron relies on XPath at two different levels: Again, an update of Schematron to support maps would be more difficult is maps are not similar to XML nodes. Exervice the place of JSON on the dml, I think that it is really important to support maps and the question we have to face is: And obviously, my preference is the later: The fact that map entries are unordered and they need to be because the properties of JSON objects are unordered is less an issue to me.
The foundation of this data model is xmml XML infosetbut it also borrows informations items from the Post Schema Validation Exerciec the [in]famous PSVI and adds its own abstract items exrecice as sequences and, new in 3. I started dd think more seriously about this, doing some researches and writing a proposal for Balisage and my plan was to wait until the conference to publish anything.
My initial motivation to propose such a format was to have a visualization of the XDM: Working on this, I have soon discovered that this serialization can have other concrete benefits: And of course, with a XML serialization that becomes trivial to do.
The URL itself exercixe This first version is not complete.
Corri already supports rather complex cases, but I need to think more how to deal with maps or sequences of nodes such as namespace nodes or attributes. So far I am really impressed by XPath 3.
I may have missed something, but in practice I have found quite difficult when you have a variable to browse its data model. This strengthen the feeling that we have a real chimera!
The Linked TEI: Text Encoding in the Web
Unfortunately, the features that are needed to do so node tests, axis, … are reserved to XML nodes. It may be too late for version 3. Going forward, we could reconsider the way these items mix and match.
Currently you can have sequences of maps, functions, nodes and atomic values, maps which values are sequences, functions, nodes and atomic values but nodes are only composed of other nodes.
In other words, I think that it would be much more coherent to treat maps and sequences like nodes…. XML Prague is also a very interesting pre-conference day, a traditional dinner, posters, sponsors announcements, meals, coffee breaks, discussions and walks that I have not covered in article for lack of time. I have found back this old feeling of being torn between two different culture very strongly this week end at XML Prague.
Some of the panelists Anne van Kesteren, Robin Berjon and myself were less hostile but the audience did unanimously reject the idea to change anything in the well-formedness rules of the XML recommendation.
Speaking of errors may be part of the problem: However, a consensus was found to admit that it could be useful to specify an error recovery mechanism that could be used when applications need to read non well formed XML documents that may be found on the wide web. What can be so fundamental with the definition of XML well-formedness?
I. Tellier : enseignement
These reactions made me feel like we were discussing kashrut rules rather than parsing rules and the debate often looked more religious than technical! The next talk, XProc: NVDL is a cool technology to bridge different schema languages and greatly facilitates the validation of compound XML documents.
Both the syntax and the extensions crrig both elegant and clever. Proposing zero based arrays inside a JSONic syntax to web developers is like wearing a kippah to visit an orthodox Jew and bring him baked ham: Norman Walsh came back on stage to xmo Corona: While Steven was speaking, Michael Kay twitted what many of us were thinking: A lot of good things indeed! And of course new types in the data model to support the JSON data model. XQuery being used to power web applications, these annotations can be used to define how stored queries are associated to HTTP requests and Adam proposes to standardize them to insure interoperability between implementations.
If xjl can use XSLT 1. A Transformation Library for XQuery 3. Taking exerice of the functional programming features of XQuery 3. Michael choose to use John Amos Comenius as an introduction for his keynote.