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RE: declarative expressons in WF2

From: Dave Raggett <dsr@w3.org>
Date: Tue, 27 Mar 2007 09:34:50 +0100 (BST)
To: "T.V Raman" <raman@google.com>
cc: mikeschinkel@gmail.com, public-html@w3.org
Message-ID: <Pine.LNX.4.64.0703270932050.5401@localhost>


On Mon, 26 Mar 2007, T.V Raman wrote:

> Note that the XForms WG originally speculated on subsetting
> JavaScript, and for the reasons you mention decided to use XPath
> instead.

Hi Raman,

I am not sure what your point is in saying that. The only real
distinction is that XPath allows for the full set of XML identifiers
which is larger than for ECMA 262, and that XForms was aligning
itself with the suite of XML specifications including XML
Schema, XSLT, and XPath, so XPath was a clear winner over
ECMAScript.

But for non-techies who don't know programming languages, but do
know simple arithmetic expressions from their school days, there are
therefore different criteria in play.

As for the issues of calling external functions it doesn't matter
what expression language you use. Static analysis of dependencies
for function bodies is impractical. So you have to constrain such
functions. That is not a problem in practice, and if necessary you
can constrain the set of such functions to a predefined set.

p.s. authoring tools could reversably translate between XPath and a 
more user friendly format, so this isn't that big of a problem.

  Dave Raggett <dsr@w3.org> http://www.w3.org/People/Raggett
Received on Tuesday, 27 March 2007 08:35:07 GMT

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