need help writing xsl for following problem:

the following will be input

<main>
<item>books</item>
<source>A</source>
<destination>B</destination>
<status>yes</status>
</main>

based on the values for source, destination and the text of shipQuery, present in the following xml (stored in c:\)... the tag status should be copied in output.

<shipQuery>
<item source='A' destination='B'>books</item>
<item source='Z' destination='default'>pen</item>
<item source='B' destination='A'>default</item>
</shipQuery>

here a default means dont care. (source/destination/item can be anything)

as we can see my output will be

<main>
<item>pen</item>
<source>A</source>
<destination>B</destination>
<status>yes</status>
</main>

if there is no match in the shipQuery xml,

<main>
<item>pen</item>
<source>A</source>
<destination>B</destination>
</main>

will be my output

how can this be achieved?

i am able to do this using the following template. but gives rise to another doubt... the status is supposed to return a node set.. but it returns either true or false. why is it so... ?

    <xsl:template name="getShipStatus">
        <xsl:param name="input"/>
        <xsl:variable name="config" select="document('c:\shipQuery.xml')"/>

            <xsl:variable name="list">
                <xsl:copy-of select="$config/item[normalize-space(.) = $input/main/item/text() or normalize-space(.) = 'default'] "/>
            </xsl:variable>
            <xsl:variable name="status">
                <xsl:copy-of select="$list//item[@source= $input/main/source/text() or @source = 'default'] and $list//item[@destination=$input/main/destination/text() or @destination = 'default']"/>
            </xsl:variable>
<xsl:value-of select="$status"/>
    </xsl:template>

Look at this expression:

select="$list//item[@source= $input/main/source/text() or @source = 'default'] and $list//item[@destination=$input/main/destination/text() or @destination = 'default']"/>


it can be reduced to

select="E[predicate1] and E[predicate2]"

The result of the "and" operator is always a boolean.

Perhaps you meant "select everything in E[predicate1] and also select everything in E[predicate2]". If so you want the union operator, written "|" , rather than the "and" operator.

Or perhaps you wanted all the Es that satisfy both predicates. In that case you want E[predicate1 and predicate2]".

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

Dear Kay... true but, the following is also a boolean expression.

<xsl:copy-of select="$config/item[normalize-space(.) = $input/main/item/text() or normalize-space(.) = 'default'] "/>

something similar to... E[predicate1] or E[predicate2]

but this returns a node set. why is this so.

The above isn't a boolean expression - it is equivalent to "E[p1 or p2]", i.e. selects all the E elements where p1 and p2 are true.

"E[p1] or E[p2]" means is there an element in E where p1 is true and an element in E where p2 is true.

The position of the square brackets is the important part you seem to be misunderstanding.



/- Sam Judson : Wrox Technical Editor -/

You seem to have got yourself very confused.

Assuming N is a node-set (or in 2.0 a node-sequence) and P, Q are boolean expressions, then

N[P and Q]

selects those nodes in N for which P and Q are both true, while

N[P or Q]

selects those nodes in N for which either P or Q is true.

If you use a node-set in a context where a boolean is expected, for example <xsl:if test="N[P or Q]">, then the result is true if the node-set is non-empty.

If you write

N[P] and N[Q]

then the expressions "N[P]" and "N[Q]" both select node-sets. The "and" operator converts these node-sets to booleans, so the result is true if neither N[P] nor N[Q] is empty. Similarly

N[P] or N[Q]

is true if either N[P] or N[Q] is non-empty.

I hope this clears things up for you.

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

yes i understood. Thanks.