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[Bug 2149] [XSLT] what parts of the dynamic context must be stable?

From: <bugzilla@wiggum.w3.org>
Date: Sat, 24 Sep 2005 22:18:35 +0000
To: public-qt-comments@w3.org
Message-Id: <E1EJILr-0000rj-C7@wiggum.w3.org>


mike@saxonica.com changed:

           What    |Removed                     |Added
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED

------- Additional Comments From mike@saxonica.com  2005-09-24 22:18 -------
Following discussion within XSL WG, I propose to replace the paragraph:

XPath requires that certain aspects of the dynamic context are stable during the
evaluation of an expression. For example, the current date and time, the
implicit timezone, the document order of nodes, and the set of available
documents (representing the results of the document and docFO functions) are not
allowed to change while an expression is being evaluated. In XSLT, these values
are required to be stable throughout the entire transformation.


A number of functions specified in [F+O] are defined to be *stable*, meaning
that if they are called twice during the same *execution scope*, with the same
arguments, then they return the same results (see F+O section 1.7]. In XSLT, the
execution of a stylesheet defines the execution scope. This means, for example,
that if the function current-dateTime is called repeatedly during a
transformation, it produces the same result each time. By implication, the
components of the dynamic context on which these functions depend are also
stable for the duration of the transformation. Specifically, the following
components defined in [XPath section 2.1.2] must be stable: function
implementations, current dateTime, implicit timezone, available documents,
available collections, and default collections. The values of global variables
and stylesheet parameters are also stable for the duration of a transformation.
The focus is *not* stable; the additional dynamic context components defined in
[XSLT section 5.4.4] are also *not* stable.

I am publishing this proposed text here for review both by the original
commenter and by the XSL WG. I'm also marking the bug as fixed: if there is any
problem with this resolution, please reopen it.
Received on Saturday, 24 September 2005 22:18:37 UTC

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