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Re: XSLT 2.0 courses?
In its original sense, bzw. (beziehungsweise) means 'respectively', but
yes, it has assumed the additional meaning of something like 'or', 'or
else', or 'or rather'.
https://en.m.wiktionary.org/wiki/beziehungsweise
'or else' is appropriate for the operator, but it might be a nightmare
grammar-wise (XPath grammar, not English grammar).
On 21.09.2020 13:01, Michael Kay mike@xxxxxxxxxxxx wrote:
Perhaps we should call it "bzw" - a German word that is sadly missing
from English.
Mike
On 21 Sep 2020, at 11:58, Imsieke, Gerrit, le-tex
gerrit.imsieke@xxxxxxxxx <mailto:gerrit.imsieke@xxxxxxxxx>
<xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx
<mailto:xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>> wrote:
Thank you, this is convincing.
One might consider naming the 'otherwise' operator 'alternatively',
but this is not the hill I'm going to die on.
Gerrit
On 21.09.2020 12:53, Michael Kay mike@xxxxxxxxxxxx
<mailto:mike@xxxxxxxxxxxx> wrote:
Well, I thought about using EBV, so it means (if ($a) then $a else
$b), but zero is falsey, so you get surprises with, for example
@price * (1 + (@VAT_Rate otherwise 0.2))
which potentially gives the wrong answer if @VAT_Rate is present but
zero. And it also gets complicated with atomization: if the attribute
is present but set to a zero length string, which way do you go?
Michael Kay
Saxonica
On 21 Sep 2020, at 11:21, Imsieke, Gerrit, le-tex
gerrit.imsieke@xxxxxxxxx <mailto:gerrit.imsieke@xxxxxxxxx>
<mailto:gerrit.imsieke@xxxxxxxxx <mailto:gerrit.imsieke@xxxxxxxxx>>
<xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx
<mailto:xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>
<mailto:xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx
<mailto:xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>>> wrote:
If the boolean variable $a is false() instead of an empty sequence,
$a otherwise $b
will return false(). This is the specified behaviour, but I find it
a bit counterintuitive. I have a slight preference for the otherwise
operator to return $b if $a is false().
Have you thought about defining the otherwise operator as "it
returns $a unless it's an empty sequence or a boolean value equal to
false(), in which case it returns $b"? I'm not sure which one will
seem more natural to most users.
Gerrit
On 21.09.2020 10:46, Michael Kay mike@xxxxxxxxxxxx
<mailto:mike@xxxxxxxxxxxx> <mailto:mike@xxxxxxxxxxxx
<mailto:mike@xxxxxxxxxxxx>> wrote:
I've been proposing ($a otherwise $b) to meet this requirement: it
returns $a unless it's an empty sequence, in which case it returns $b.
For example @price - (@discount otherwise 0)
It's actually implemented in Saxon 10 if you switch syntax
extensions on.
Michael Kay
Saxonica
On 21 Sep 2020, at 02:34, Pieter Lamers pieter.lamers@xxxxxxxxxxxx
<mailto:pieter.lamers@xxxxxxxxxxxx>
<mailto:pieter.lamers@xxxxxxxxxxxx
<mailto:pieter.lamers@xxxxxxxxxxxx>>
<mailto:pieter.lamers@xxxxxxxxxxxx
<mailto:pieter.lamers@xxxxxxxxxxxx>
<mailto:pieter.lamers@xxxxxxxxxxxx
<mailto:pieter.lamers@xxxxxxxxxxxx>>>
<xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx
<mailto:xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>
<mailto:xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx
<mailto:xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>>
<mailto:xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx
<mailto:xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>
<mailto:xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx
<mailto:xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>>>> wrote:
Hi,
An avid user of ($a, $b)[1] myself, which winks at TransactSQL
ISNULL($a, $b) and MySQL IFNULL($a, $b), I do have to remind
myself that $a has to be a single item for the /if/else /shortcut
to work.
So, in
let $a := ('one','two','three')
let $b := ('none')
return ($a, $b)[1] will return just the first item in the
sequence, 'one', and not 'one','two','three', which might be what
you want to achieve in this quasi shorthanded /if/else /construction.
Not that you wouldn't know, Liam, just as a heads up to some
others in this audience who might not.
Best,
Pieter
On 19/09/2020 01:54, Liam R. E. Quin liam@xxxxxxxxxxxxxxxx
<mailto:liam@xxxxxxxxxxxxxxxx> <mailto:liam@xxxxxxxxxxxxxxxx
<mailto:liam@xxxxxxxxxxxxxxxx>> wrote:
On Fri, 2020-09-18 at 19:31 +0000, Wendell
Piezwapiez@xxxxxxxxxxxxxxx <mailto:Piezwapiez@xxxxxxxxxxxxxxx>
<mailto:Piezwapiez@xxxxxxxxxxxxxxx
<mailto:Piezwapiez@xxxxxxxxxxxxxxx>>
wrote:
Hi,
In addition to Liam's list I think there are a couple more vital
features
one needs to get a taste of in XSLT 2.0 or XSLT 3.0, if one has been
subsisting on an XSLT 1.0 diet:
* <xsl:for-each-group> and its uses
* temporary trees -
* regex support in functions and xsl:analyze-string
* tunnel parameters?
Yeah, those are all huge, although i think easier to learn than
things
like ($a, 'none')[1], which are startling because XSLT 1 didn't have
sequences.
For those wondering, ($a, $b, $c, ...)[1] returns the first non-empty
non-false item out of $a, $b and $c, so it's a shortcut for
B B B B <xsl:sequence select="if ($a) then $a else $b" />
On regular expressions - it's huge, but it's also dangerous, as e.g.
replace(price div 100, '\.\d*$', '') is not a good way to write
math:floor().
An XSLT-3-from-scratch course could easily take a full week and be
woefully incomplete. Or totally overwhelming. Or both.
On the other hand, i try & include "don't be afraid of the specs" in
the courses i teach, and then not cover every detail. So maybe it's
possible.
Liam
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