----- Original Message ----- From: "Ovidiu Predescu" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]> Sent: Monday, May 20, 2002 10:03 PM Subject: Re: Flow and XMLForm
<snip/> > > Are suggesting that the flow layer with the addition of some kind of > > Schematron processor could completely replace XMLForm? And if so, could > > you elaborate why you think this would be a better solution? > > With respect to the ability to handle user input for editing an XML > document, if you look at the functionality provided by the two, they > are very similar. Nothing prevents implementing an XMLForm-like > processor on top of the control flow engine. Whether this would be > better I don't know, I can't say anything until such a thing is > implemented. I was just observing that the overlap between the two > things. > > > Also, are you thinking of something like Rhino on the server so that > > validation could be done by similar javascript on both client/server? > > Yes, the current control flow layer uses a modified version of Rhino > on the server side. It should be possible to write the validation code > directly in JavaScript, and have it run both on the server and on the > client browser. > > JavaScript client validation improves the user experience quite a bit, > so I think a validation solution should generate both client and > server side validation code. > > > Finally, I think transforming Schematron to javascript could be very tricky. > > Something like <assert test=".!=''"> might be easy enough to transform, > > or even <assert test="/NAME_PREFER!=/NAME_ALIAS_FIRST">, but what about > > <assert test="not(contains(translate(.,'!@#$%^&*()_+-=0123456789',' > > ************************'),'*'))"> > > The nasty problem here is that the "conditional" part of an assert > > is unparsed character data, not xml markup, and so (almost) impossible > > to transform. Seems like you would need to use a constraint description > > language that expresses more of its content in "pure" XML (perhaps XMLSchema??). > > Or perhaps some even more abstract XML "model/constraint expression syntax" > > which could be translated into XMLSchema, Schematron, or client/server > > javascript as needed, i.e: > > <validation-rule> > > <validation-test> > > <instance-node name="LAST_NAME" type="String" /> > > <contains>!@#$%^&*()_+=0123456789</contains> > > </validation-test> > > <message>Last Name contains an illegal character.</message> > > </validation-rule> > > (A very crude example, but you get the idea...) > > Yes, this is what I had in mind. You're right, transforming a > Schematron document in JavaScript could be a difficult task. A > constraint language as you describe above would be better, since > writing a translator to JavaScript is much easier. However the > expressiveness of such a language is lower than that of an XPath-based > description. > > So there are three ways an XMLForm-like capability could be > implemented: > > - translate today's XPath-based Schematron to JavaScript scripts for > both client and server side > > - translate a constraint expression syntax, not based on XPath, to > JavaScript for client and server side > > - write the validation functions in JavaScript, same scripts being > used on the server and client side. > > I don't know about you, but the last approach looks to me being the > easiest one to implement (basically write your scripts). One problem I > see with it though is ties the validation to JavaScript, making it > difficult to support clients that don't run JavaScript, like browsers > on WML phones (although the language used is very similar). Just a note in regard to client/server side validation. New generation browsers support XSLT. Which means that Schemtron validation can be run on the client as well. Haven't tried it myself. I am speculating that XML standards will be better supported in the long run than ECMAScript based languages. > > Cheers, > -- > Ovidiu Predescu <[EMAIL PROTECTED]> > > >>> I'm in the job market again, check out my resume and qualifications at: > http://www.geocities.com/SiliconValley/Monitor/7464/ (GNU, Emacs, other stuff) > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, email: [EMAIL PROTECTED] > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, email: [EMAIL PROTECTED]
