RE: [xsl] Implementing a (fairly) complex business rule

["Bradley, Peter" <pbradley@xxxxxxxxxx>]

-----Original Message-----
From: Michael Kay [mailto:mike@xxxxxxxxxxxx]
Sent: 30 September 2008 16:28
To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
Subject: RE: [xsl] Implementing a (fairly) complex business rule

>If you're using data-oriented XML with element-only content (no mixed
>content, no comments or processing-instructions) then the only time
>you might use text() is in a conditional: <xsl:if
>test="MIDDLE_NAME/text()"> which will be false if there is no
>MIDDLE_NAME element or if there is a MIDDLE_NAME element and it is
>empty (more strictly, if every MIDDLE_NAME child of the context node
>is empty). But I prefer to write this as test="string(MIDDLE_NAME)",
>or as test="normalize-space(MIDDLE_NAME)" if I also want to exclude
>the case where the value exists but contains whitespace.

...

>A special case is what one might call "abnormal mixed content", where
>the structure is that of mixed content but the semantics are
>unorthodox: for example
>
> <date>2008-09-30
>  <source>estimated</source>
>  <calendar>Gregorian</calendar>
> </date>
>
>(It would be more usual to use attributes here rather than child
>elements; but one also sees comments used.) In such a case you may
>need to find the text node (or all the text nodes) explicitly using
>path expressions.

I can't thank you guys enough.  I feel I have a much better
understanding now.

As I've said, the stuff here is all data-oriented, so we don't have to
worry about mixed content or anything like that.

For now, I'm doing this for the <POSTCODE> element:

<!-- NULL is valid for a postcode -->
<xsl:if
test="/s0:HesaSqlExplicit_Response/s0:Institution/s0:Student/s0:Instance
/s0:REDUCEDI = '00'">
  <xsl:if test="s0:DOMICILE='XF' or s0:DOMICILE='XG' or s0:DOMICILE='XH'
or s0:DOMICILE='XI' or s0:DOMICILE='XK' or s0:DOMICILE='XL' or
s0:DOMICILE='GG' or s0:DOMICILE='JE' or s0:DOMICILE='IM'">
    <POSTCODE>
      <xsl:if test="not(s0:POSTCODE/text())">
        <xsl:attribute name="ReasonForNull">
          <xsl:text>1</xsl:text>
        </xsl:attribute>
      </xsl:if>
      <xsl:if test="s0:POSTCODE/text()">
        <xsl:value-of select="s0:POSTCODE/text()"/>
      </xsl:if>
    </POSTCODE>
  </xsl:if>
</xsl:if>

I guess that the text() in <xsl:value-of select="s0:POSTCODE/text()"/>
is redundant, but everything appears to be working, so using the, "If it
ain't broke don't fix it" rule, I've left it in.

We'll know better next time.

My next step is to do an audit of the elements where we've used the
string-length() test, and to change them where necessary.

Cheers


Peter