Re: [xsl] XSLT 2.0 courses?

["Pieter Lamers pieter.lamers@xxxxxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

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 wrote:
> On Fri, 2020-09-18 at 19:31 +0000, Wendell Piez wapiez@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 $c, so it's a shortcut for
>      <xsl:sequence select="if ($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
>
-- 
Pieter Lamers
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