Re: [xsl] Is there any benefit to creating a variable and specifying as="xs:string"?

["Martin Honnen martin.honnen@xxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

Am 09.06.2024 um 11:25 schrieb Martin Honnen martin.honnen@xxxxxx:
> Am 09.06.2024 um 11:19 schrieb Roger L Costello costello@xxxxxxxxx:
>
> > I have this xsl:param at the top of my XSLT program:
> >
> > <xsl:param name="ICAO" />
> >
> > Is there any benefit to adding this "as" clause:
> >
> > <xsl:param name="ICAO" as="xs:string"/>
> >
> > That "as" clause says the ICAO param is a string value. Well,
> > everything is a string. These are all strings -- '123', 'true',
> > 'http://www.example.com', '01101' -- all of which should not be used
> > to populate the ICAO param. It seems to me that adding the "as" clause
> > provides zero benefits. In fact, it has disadvantages: it makes the
> > code more verbose, it requires more typing. Do you agree that adding
> > the "as" clause provides no benefits?
> >
> > Bonus question: The value to populate the ICAO param should be a
> > 4-letter, uppercase value, such as KBOS. Is there anyway to express
> > that requirement/constraint in the "as" clause?
>
> Perhaps in XSLT 4
>  B B  as="enum('KBOS')"
> Of course an enumeration requires you to be able to list the possible
> values.


In Saxon 12.4 (tested with EE but should work with PE as well, I think)

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
  version="4.0"
  xmlns:xs="http://www.w3.org/2001/XMLSchema";
  exclude-result-prefixes="#all"
  expand-text="yes">

  <xsl:item-type name="ICAO-type" as="enum('KBOS')"/>

  <xsl:param name="ICAO" as="ICAO-type"/>

  <xsl:template match="/" name="xsl:initial-template">
    <test>{$ICAO}</test>
  </xsl:template>

</xsl:stylesheet>


Passing params on the command line (for XSLT 4 I think you need
--allowSyntaxExtensions:on) can then be done with e.g.

    ?ICAO="'KBS'"

giving

Type error on line 13 column 6 of param-as-enum-test3.xsl:
  XPTY0004  The required item type of the value of variable $ICAO is
enum("KBOS"); the
  supplied value "KBS" does not match.
In template xsl:initial-template on line 12 column 4 of
param-as-enum-test3.xsl:
The required item type of the value of variable $ICAO is enum("KBOS");
the supplied value "KBS" does not match.



If you pass e.g.

   ?ICAO="'KBOS'"

the value is accepted. Of course for a single value you probably don't
need an enum but I hope if you have a list of allowed values this helps.