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While debugging my stylesheet using XMLSpy, I got a really weird result:
<xsl:if test="$match = true()"> matches even if $match is an empty node
fragment. How can this be?

--
Victor

In article <c82liu$rqk$>,
Victor <engmark-> wrote:

>While debugging my stylesheet using XMLSpy, I got a really weird result:
><xsl:if test="$match = true()"> matches even if $match is an empty node
>fragment. How can this be?

What do you mean by "empty node fragment"? Do you mean "empty node set",
"empty result tree fragment", or what?

If the value of $match is a node set, then "$match = true()" is true
if and only if the node set is non-empty.

If the value of $match is a result tree fragment, then it is
"equivalent to a node-set containing just a single root node" (section
11.2) so it is never empty and "$match = true()" is always true.

I suspect this is different in XSLT version 2, which might explain why
different versions of Saxon and Xalan give me different results when I
test it.

-- Richard

Richard Tobin wrote:

> In article <c82liu$rqk$>,
> Victor <engmark-> wrote:
>
>
>>While debugging my stylesheet using XMLSpy, I got a really weird result:
>><xsl:if test="$match = true()"> matches even if $match is an empty node
>>fragment. How can this be?
>
>
> What do you mean by "empty node fragment"? Do you mean "empty node set",
> "empty result tree fragment", or what?
>
> If the value of $match is a node set, then "$match = true()" is true
> if and only if the node set is non-empty.
>
> If the value of $match is a result tree fragment, then it is
> "equivalent to a node-set containing just a single root node" (section
> 11.2) so it is never empty and "$match = true()" is always true.

A-hah! Thank you, this seems to solve the mystery (especially since the
XSL spec says empty node sets equal false().

--
Victor