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RE: advice on node-set fallback needed

2003-08-19 01:19:59
Thanks Mike.

Are you saying MSXML4 gives you a compile-time error for a path
expression that misuses an RTF?

Yes.

The XSLT 1.0 spec is very unspecific about which errors are compile-time
errors and which are run-time. The spec merely says that this operation
"is not permitted". But you should be able to get it to compile by using
forwards-compatible mode, which you can invoke by setting version="2.0"
(or any value other than 1.0).

So I'm now trying:

  <xsl:choose>
    <xsl:when test="function-available('exsl:node-set')">
            <xsl:text>exsl: </xsl:text><xsl:value-of
select="name(exsl:node-set($test)/node())" />
    </xsl:when>
    <xsl:when test="function-available('msxsl:node-set')">
            <xsl:text>msxsl: </xsl:text><xsl:value-of
select="name(msxsl:node-set($test)/node())" />
    </xsl:when>
    <xsl:otherwise>
            <xsl:text>(none): </xsl:text><xsl:value-of version="2.0"
select="name($test/node())" />
   </xsl:otherwise>
  </xsl:choose>

However this breaks execution in Saxon 6.5.3 and MSXML completely:

(MSXML3 and MSXML4)

Error occurred while compiling stylesheet 'test.xslt'.

Code:   0x80004005
Attribute 'version' is invalid on 'xsl:value-of'.

(Saxon)

  Attribute version is not allowed on this element
Transformation failed: Failed to compile stylesheet. 1 error detected.


Using xsl:version instead of version yields:

(MSXML3)

Works.

(MSXML4)

Error occurred while compiling stylesheet 'test.xslt'.

Code:   0x80004005
Expression must evaluate to a node-set.

name(-->$test<--/node())

(Saxon)

  Attribute xsl:version is not allowed on this element
Transformation failed: Failed to compile stylesheet. 1 error detected.


What *does* seem to work is setting version="2.0" on the stylesheet element
itself. However I'm a bit concerned that this will instruct an XSLT 2.0 in a
non-XSLT-1.0 compatible manner.

However, this:

  <xsl:choose>
    <xsl:when test="function-available('exsl:node-set')">
            <xsl:text>exsl: </xsl:text><xsl:value-of
select="name(exsl:node-set($test)/node())" />
    </xsl:when>
    <xsl:when test="function-available('msxsl:node-set')">
            <xsl:text>msxsl: </xsl:text><xsl:value-of
select="name(msxsl:node-set($test)/node())" />
    </xsl:when>
    <xsl:when test="system-property('xsl:version') &gt;= 2.0">
            <xsl:text>(XSLT2.0): </xsl:text><xsl:value-of version="2.0"
select="name($test/node())" />
    </xsl:when>
    <xsl:otherwise>
            <xsl:text>no way</xsl:text>
   </xsl:otherwise>
  </xsl:choose>

seems to work with all 1.0 processors I tried, and should also work on an
XSLT-2.0 processor without exslt:node-set(), right?

The rules for what a 2.0 processor should do when given a stylesheet
that says version="1.0" have not fully stabilised, but the next version
of the spec is likely to say that the processor should give a warning
about possible incompatibilities, and then execute the stylesheet in
backwards-compatible mode. It should not disallow use of 2.0 features
just because the stylesheet says version="1.0". In this case, however,
your stylesheet is using a 2.0 feature so it should say version="2.0".

Michael Kay

Thank for the help,

Julian

--
<green/>bytes GmbH -- http://www.greenbytes.de -- tel:+492512807760


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