Subject: Re: [xsl] Where is 'intersect' Operator Defined in XPath 3? From: "Imsieke, Gerrit, le-tex gerrit.imsieke@xxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> Date: Mon, 8 Aug 2022 23:35:26 -0000 |
Union, intersection, and set difference on node sequences are not covered in the F&O spec; unless I have overlooked them, neither are "to" (as in "1 to 100"), "and", "or", "not", "if" ... "then" ... "else", "instance of", "treat as", "castable as", "cast as".
Similarly "/", "!", "?", "[".."]", "=>", "is", "<<", ">>", ",", "||". And the general comparison operators are defined in the XPath spec by reference to primitives defined in F&O.
In fact at 3.1 the only operators defined in F&O are the arithmetic and value comparison operators, and I think the reason for this was indeed division of editorial labour rather than convenience for the reader. The WGs always recognized that this was less than satisfactory, but failed the find the energy to perform the major refactoring needed to improve matters.
There was some tidying up between 3,0 and 3.1. In 2.0 and 3.0 some operators such as union, intersect, except, "<<", ">>" were defined in both specifications, and there was nothing to say which was normative. It was felt that the simplest solution to the duplication was to remove the operators from F&O, which had the effect that the syntax and semantic rules could be found in the same place.
Michael Kay Saxonica
These are all keywords in XPath and must be (and are) defined in the XPath spec.
Perhaps some illogicality arose in the division of labor made when the detailed documentation of the function library was split off from the XPath spec into a separate document. Or perhaps there is a definition of "operator" somewhere that explains all.
In either case, it doesn't seem quite as accidental as Mike Kay's self-depreciating account might suggest.
Michael Sperberg-McQueen
On Mon, Aug 8, 2022 at 10:14 AM Michael Kay mike@xxxxxxxxxxxx <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
I'm afraid the distribution of text between the various specs often owes more to the question of who stepped up to do the editorial work than to any top-down design of the document suite.
Michael Kay Saxonica
On 8 Aug 2022, at 16:54, Norm Tovey-Walsh ndw@xxxxxxxxxx <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
"Eliot Kimber eliot.kimber@xxxxxxxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> writes:I was looking in the XPath 3.1 functions and operators docbso I think my question still standsbwhy do I not find a definition of the intersect operator in the Functions and Operators spec?
I donbt know if therebs a good editorial reason, or if itbs simply a matter of oversight. I donbt think it would have been unreasonable to expect an bop:intersectb function described in F&O with a pointer from the bintersectb operator in XPath to that function. But thatbs not the way the XPath spec got written. B/\_(c)_/B/
And also why does a google search not find the entry in the XPath spec?
According to a bit of spam that drifted past me today, Google/Alphabet are engaged in a broad program of mind control over the entire human race. Perhaps theybre distracted a bit from the search engine business.
Be seeing you, norm
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