On 13/03/2014 10:59, Ihe Onwuka wrote:
e for-each syntax is more verbose.
Muenchian grouping is not something I burden my short term memory
with because I hardly ever use it and and it's a phrase that is
meaningless beyond a very select cognoscenti. What I posted can
literally be described to a layman - add all the B/Dates that aren't
in the set of A/Dates additionally it literally translates it into a
set-theoretic
Not at all in an internet age, "muenchian grouping" might be an
arbitrary label, but if you (or rather I) call it that rather than call
it "the grouping idiom using keys that used to be needed in XSLT1"
then you have a high probability of getting an exact description and
code samples if you type it into google.
A union (B diff A)
That's why I prefer it.
But as I say if you have more than a dozen or so elements in your list
you are likely to be able to observe the time difference.
this will (unless you have a very aggressively optimising XSLT
engine) be quadratic in performance as the full A list is going to
be searched for every B.
good point. If and when the volumes warrant performance tuning I'll
know where to start.
Also of course using text() rather than
<xsl:apply-templates select="A/Date | B/Date[not(current()/A/Date =
.)]>
means the code is very fragile and will break if comments spit up
the text nodes.
I have been doing too much XQuery recently,
The same advice not to use text() applies equally to XQuery.
but is . robust against changes to the content model?
well you were already using it for sorting, and if if the content model
changes then any of this could break. if Date became
<Date><year>2014</date><moth>03</month><day>13</day></Date>
then . would keep working but text() would break.
David
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