I have the following problem:

I have to visit the childs of a particular parent node and when I find some particular information in one of that childs I have to produce something in the output.At this moment I dont need visting more childs because I dont have to produce this outuput again.

Ive done this with a xsl:for-each loop and I know I cant break out the loop like in other prgramming languages(all nodes are visited in parallel).

I would like to know if there is any pattern I can use to find if there is a child node containig the specific information I'm looking for.

XML INPUT
---------

<a>
    <b>
        <c>FOO </c>
    </b>
    <b>
        <c>BANANA </c>
    </b>

    <b>
        <c>FOO </c>
    </b>
</a>

You need to write a predicate that describes which nodes are to be processed. For example, to process the first three children:

<xsl:for-each select="*[position() &lt; 4]">

to process all nodes provided they are followed by a BANANA node:

<xsl:for-each select="*[following-sibling::b[c='BANANA']]">

Sometimes it's not possible to do in that way, in which case you have to traverse the children using sibling recursion. (apply-templates to the first child, which it turn does apply-templates to the next child, and so, on passing any accumulated information in parameters).

Or in XSLT 2.0 you can use xsl:for-each-group.

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

Which will be the pattern to select all the nodes 'b' that have a node 'c' with text different to 'FOO'.

XML INPUT
---------

<a>
    <b>
        <c>FOO </c>
    </b>
    <b>
        <c>BANANA </c>
    </b>

    <b>
        <c>FOO </c>
    </b>

    <b>
        <c>JOE </c>
    </b>
</a>

Group to select {BANANA,JOE}

Maybe something like:

 <xsl:for-each-group select="b[c/text() != 'LOS']">

Thanks for the help.

Maybe using group-by?