possible to mimic while-like behavior?

I know there are only two conditionals possible in xsl stylesheets,
<xsl:if> and <xsl:choose> (inside which one has <xsl:when> ... </xsl:when>
and <xsl:otherwise>...</xsl:otherwise> with nesting allow).

However, there is no "while" or "until".

Imagine,
<xsl:for-each select="foo">
 <xsl:choose>
  <xsl:when test="bar">blah</xsl:when>
  <xsl:otherwise>blort</xsl:otherwise>
 </xsl:choose>
</xsl:for-each>

Now imagine that when the conditions are such that <xsl:otherwise> is
matched, one wants to break out of the <xsl:for-each>.

e.g., speaking in a Perl-esque way, I want
  while ($foo != "bar") {
    blah
  }

Is there any way to simulate, hack, or otherwise achieve this?

thanks again,
-carole
- - - - - - - - - - - - - - - - - - - - - - - - - 
Carole E. Mah                Carole_Mah@xxxxxxxxx
         Senior Programmer/Analyst
  Brown University Scholarly Technology Group
            phn 401-863-2669
            fax 401-863-9313
         http://www.stg.brown.edu/
 personal: http://www.stg.brown.edu/~carolem/


 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list