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[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] RE: [SUMMARY #1] Why is there little usage of XML on the 'v
Didier PH Martin said: > Hello Juan, Hi, > Didier replies: > A lot of languages based on XML were developed but few have practical > interpreters associated to them. For instance, CML has several > interpreters able to translate elements of the language into visible > objects. XBRL has several interpreters able to process the language > elements into spreadsheets and more elaborate models (for stock > picking). A language based on XML becomes useful when processors are > also provided with it; otherwise it is only the result of some spare > glucose metabolism and not a useful tool :-) > > If you count XML based languages having a set of interpreters made > available for public consumption, the number of 600 is reduced to less > than 50 (and I am overly optimist here) Well i obtained the number from [http://www.tbray.org/ongoing/When/200x/2006/01/08/No-New-XML-Languages] See also [http://xml.coverpages.org/xmlApplications.html] I did not check the implementation level of development of each one. > Didier replies: > Juan, the DOM is only an interface to something else. It's an > abstraction or a facet offered for public consumption, it's not the > object per se. A DOM is a public interface but behind the curtain you > have something else. For example, in the Gecko engine, each HTML element > is translated (i.e. interpreted) into a visual object. Idem for IE. > Visual objects have several properties set by either HTML element > attributes like for instance the width or height (when available) or set > by CSS properties. Thus, the real object presenting a DOM interface is a > lot more than the DOM. It's a set of methods and properties some made > public like the DOM some made private. It is also an area laid on a 2D > layout, hence the notion of visual object. In the case of VoiceXML, the > result of the interpretation is sound. Hence the notion of aural objects > placed in a time sequence. The real object keeps some properties like > the element tag, this is why we can retrieve its origin. But also, at > least in the case of IE, if you request a serialization of its current > state you'll get all properties attached to the object. The ones defined > as attribute in declarative code (for the browser an HTML document is > declarative code) and the one dynamically attached to the object at > run-time. <div> and <p> inherit from the same "block area" object and > the object inheriting the "block area" features add some properties and > methods, they may be different though even they are both a "block area". > The world as seen by the browser is clearer when seen through its own > perspective or the object oriented perspective. For a browser an HTML > element is no longer and solely an HTML element, it became something > else an aggregation of different things {a visual object, a DOM object, > an ECMAScript object, etc...} At run-time and within a browser an HTML > is a lot more than specified at first in with markups. Now understand you. > Didier replies: > XSLT can be perceived as a general purpose XML interpreter. It allows > you to assemble different XML documents into a single one, have > different interpretation strategies for each fragment or vocabulary. For > instance, I can add new vocabularies to an XHTML document and provide an > XSLT template that will use other template/interpreter for other > vocabularies I am including in the XHTML document. This way, the > language becomes eXtensible. Yes, but is not eXtensible in that way i said. Reason that if you have a <grocery-list> at the server side and you can manipulate the semantics, but you finalize with something as <ul> at the client side if you want your doc can be 'understood'. The situation is still poor when you cannot rely on a XSLT or CSS for full funcionality: e.g. CML. Different XML tags cannot be asembled in the way i said. That is reason that new tags may be invented. E.g. XHTML2 <blockcode> for the current sequence of <pre><code>. If you can combine available tags in a multimarkup system then you can directly use something like the composed tag <<pre><code>>. You cannot do this in XML and, therefore, XHTML WG needs add a _new_ tag: <blockcode>. When explosion of languages arise in a future, the posibility for reusing available tags -instead invent new ones- will become so crucial like combination of fragments of code in PL. > Didier replies: > Yes this is what I mean. In the last project I was working on for > several years and that was maybe the most ambitious AJAX based project I > came to the conclusion that what is needed in an intelligent > interpreter. In many cases, the system was not responding because the > pre-conditions weren't met and no intelligent message was provided to > the users. So I started to display messages about what the engine is > doing, then I still got the same precondition errors when, for example, > the users disabled the javascript option. So, I am updating the engine > with a new algorithm > > a) check pre-condition: for example, the very first condition for the > engine to run is to have javascript enable. If not, the engine should > display an error message and a procedure for users to set the javascript > to on or make this site as "trusted". So, not only providing an error > message but also indicating what to do. Same thing if the java VM is > disabled, etc... This is why I came to the conclusion that an > environment has to be defined for a proper interpretation (an > interpretation being in my case a rendition). Based on this definition, > the layer provided for the datument can check if the latter can survive > in this host. If not, at least the user is made aware of what is wrong > and what to do. Interesting, because i suspect i would find a similar problem with a project i have in my mind now. > Cheers > Didier PH Martin > http://didier-martin.com Juan R. Center for CANONICAL |SCIENCE)
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