Re: [xsl] First steps with high order functions

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

On 19.06.2018 12:33, Christophe Marchand cmarchand@xxxxxxxxxx wrote:

> I'm trying to learn high order functions, and I have some difficulties. 
> If someone could help...
>
>
> I have a normal function :
>
>  B  <xsl:function name="nu:camelCase" as="xs:string?">
>  B B B  <xsl:param name="s" as="xs:string?"/>
>  B B B  ...
>  B  </xsl:function>
>
>
> I want to apply it on each word of a sentence :
>
>  B  <xsl:function name="nu:clearUsername" as="xs:string?">
>  B B B  <xsl:param name="name" as="xs:string?"/>
>  B B B  <xsl:choose>
>  B B B B B  <xsl:when test="empty($name)"><xsl:sequence select="()"/></xsl:when>
>  B B B B B  <xsl:when test="contains($name, ' ')">
>  B B B B B B B  <xsl:variable name="temp" select="tokenize($name, ' ')"/>
>  B B B B B B B  <xsl:sequence select="string-join(for-each($temp, 
> nu:camelCase#1), ' ')"/>
>  B B B B B  </xsl:when>
>  B B B B B  <xsl:otherwise>
>  B B B B B B B  <xsl:sequence select="$name"/>
>  B B B B B  </xsl:otherwise>
>  B B B  </xsl:choose>
>  B  </xsl:function>
>
> Does the for-each is correct ? 

I think it should work as long as the higher-order function feature is 
supported.

> Is there another syntax to make this work 
> with Saxon-HE ?

Saxon 9.8 HE doesn't support the higher-order function feature so using 
the "for-each" function with it is not possible.

https://www.w3.org/TR/xpath-functions/#func-for-each however explains

  for-each($SEQ, $F) is equivalent to the expression for $i in $SEQ 
return $F($i), assuming that ordering mode is ordered.

so you can use
  for $i in $temp return nu:camelCase($i)

to avoid the use of the "for-each" function.

> Is there a better way to do this ?

If you learn XPath 3.1 you could also try to get accustomed to be arrow 
operator and use

  $name => tokenize(' ') => for-each(nu:camelCase#1) => string-join(' ')

in the long run that might be more readable then the nesting of function 
calls.