Re: [xsl] Comparing nodes minus one child

[Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>]

Matt:

I assume by "compare" you mean compare their string values. Comparing node 
identity is not really practical in XSLT 1.0, nor even called for here.

At 03:37 PM 9/25/01, you wrote:
>     If I have two elements that have the same structure in two
> variables(today_product and yesterday_product):
>      <Product>
>           <Child1>...</Child1>
>           <Child2>...</Child2>
>           ...
>           <ChildX>...</ChildX>
>      </Product>
>
> How can I compare the two <Product> elements by comparing everything but
> <ChildX> to see if they are equal?  If possible, I would like to do this in
> one line as opposed to comparing each part, which I can already do.

You can do it in one line, if you set up some other lines to support your 
one-line comparison.... I hope that's good enough.

Basically the trick is to use a mode to load variables with the values you 
want; then compare the variables.

For example, you could say

<xsl:variable name="prod-1-value">
  <xsl:apply-templates select="$today-product" mode="product-compare"/>
</xsl:variable>

<xsl:variable name="prod-2-value">
  <xsl:apply-templates select="$yesterday-product" mode="product-compare"/>
</xsl:variable>

(Note this will only work if $today-product and $yesterday-product are 
actually nodes, not RTFs.)

Then have a separate template to say

<xsl:template match="ChildX" mode="product-compare"/>

which will remove the ChildX node from the RTFs created for the variables. 
(The others will be included by default.)

Comparing the prod-1-value and prod-2-value RTFs will work as a string 
comparison.

If plain string comparison isn't strong enough, you could provide the 
strings with pseudo-markup by doing something like

<xsl:template match="*" mode="product-compare">
  <xsl:value-of select="concat('[', local-name(), ']')"/>
  <xsl:apply-templates mode="product-compare"/>
</xsl:template>

which will prefix each element's value with a "tag" (thus making your 
string comparison more robust).

If you're curious (and can't already see it in your head), dump the 
variables out to look at them before you compare them.

> i.e.  today_product (minus ChildX) ?= yesterday_product (minus ChildX)

I hope that helps.

Cheers,
Wendell



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Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
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