Re: [xsl] Breaking from the loop (for-each or apply-template)

[Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>]

Hi,

The specification of xsl:message is soft, the instruction optional, and not 
all processors support it. I suppose this softness is simply out of a 
recognition that not all architectures are equally able to provide the 
functionality.

A more conventionally XSLT-ish way to approach the problem would be to 
define the error condition up front and simply design the stylesheet to 
return warnings instead of (or in addition to) the usual thing, if any 
error conditions obtain. So for example if I defined my condition as "all 
<value> elements must have content that casts to a number" (so, for 
example, "0" is okay but not just whitespace) and my input had (somewhere 
inside)

<value>5</value>
<value>9</value>
<value></value>
<value>Hooey!</value>

my XSLT could have

<xsl:variable name="errors" select="//value(not(number(.))"/>

<xsl:template match="/">
  <xsl:choose>
    <xsl:when test="$errors">
      <!-- erroneous 'value' elements are found -->
      <xsl:apply-templates select="$errors" mode="report-errors"/>
    </xsl:when>
    <xsl:otherwise>
      <!-- no errors: process normally -->
      <xsl:apply-templates/>
    </xsl:otherwise>
  </xsl:choose>
</xsl:template>

As noted above, you could leave out the xsl:choose and have the errors 
reported in addition to, rather than instead of, normal output.

Note that this approach only works on "errors" that can be defined ahead 
and that appear within otherwise proper well-formed XML.

Also, no "loop" is being "broken" -- no specification of flow of control is 
really needed here, just a plain old declaration that "if X is true, I want 
X', otherwise I want Y".

Cheers,
Wendell

At 03:20 PM 8/12/2005, you wrote:
> Oleg,
>
>     I've never used Cocoon, but I can tell you that Xalan 2.5.1 and
> above (2.7 was released a few days ago) do support the xsl:message
> instruction.
>
> Regards,
> Kenneth


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Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
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