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Re: a nicer total sibling count than this

2002-09-18 12:58:34

--- scruss at sympatico dot ca wrote:


I'm working with a dictionary marked up in XML. Conventionally, one
numbers definitions (def elements here)  only if there are two or
more
definitions for the given part of speech. 

To my surprise and delight, the following worked, producing heavy def
numbers with a following non-break space:

 <xsl:template match="def">
  <xsl:if test="(count(preceding-sibling::def) +   
                 count(following-sibling::def)) >= 1">
   <xsl:element name="strong">
    <xsl:number/>
    <xsl:text> </xsl:text>
   </xsl:element>
  </xsl:if>
  <xsl:apply-templates/>
 </xsl:template>

Is there a prettier/more efficient way of doing the same thing
without
resorting to frankly ugly
'(count(preceding-sibling::def)+count(following-sibling::def))'?

thanks,
 Stewart


Hi Stuart,

count(preceding-sibling::def) +   
                  count(following-sibling::def) >= 1

is equivalent to:

preceding-sibling::def or following-sibling::def

The latter may be significantly optimised by a clever XSLT processor,
because:

1. for either of 
    preceding-sibling::def 
and
    following-sibling::def

it is only necessary to see that a single (at least one) node is
returned by the corresponding expression. This contrasts sharply with
using count(), in which case all nodes in a (potentially long) node-set
have to be counted.

2. If preceding-sibling::def has at least one node, then there's no
need at all to evaluate (the other operand of "or") 
following-sibling::def




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