Re: What is the value of an undefined param

[Wendell Piez <wapiez at mulberrytech dot com>]

To expand on David's lucid explanation of Jonathan's problem....

At 11:02 PM 3/21/00 GMT, David wrote:
><xsl:param name="x" select="'no-supplied-value'"/>
>
>then <xsl:if test="$x='no-supplied-value'"> is probably only true if a
>value wasn't supplied. (ie it would also be true if somone maliciously
>supplied the value 'no-supplied-value'

Setting the parameter default as

<xsl:param name="x" select="false()"/>

The value of $x is a Boolean false (XPath 4.3). Then the test

<xsl:if test="$x"> ... </xsl:if>

will fail unless the default is overridden by a parameter passed in.

This also makes it a bit harder for that malicious
passer-of-misleading-parameters.

Fun.
--Wendell (as usual, standing on others' shoulders)


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Wendell Piez                            mailto:wapiez@mulberrytech.com
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