spliting a string

hi

i have the following template which splits a string to tokens elements
when ever a delimiter occurs  :

<xsl:template name="tokenizer">
  <xsl:param name="string" />
  <xsl:param name="delimiter" select="' '" />
  <xsl:choose>
   <xsl:when test="$delimiter and contains($string, $delimiter)">
           <token>  <xsl:value-of
select="substring-before($string,$delimiter)" /> </token>
           <xsl:call-template name="tokenizer">
           <xsl:with-param name="string"
select="substring-after($string,$delimiter)" />
           <xsl:with-param name="delimiter"     select="$delimiter" />
           </xsl:call-template>
    </xsl:when>
    <xsl:otherwise>
    <token>  <xsl:value-of select="$string" /></token>
    </xsl:otherwise>
 </xsl:choose>
 </xsl:template>



if we run the above template over the following string :

i have 22xxxxx+10  elements in my database+10yyyyyy  attribute for each

 we get the following result:

<token>i</token>
<token>have</token>
<token>22xxxxx+10</token>
<token>elements</token>
<token>in</token>
<token>my</token>
<token>database+10yyyyyy</token>
<token>attribute</token>
<token>for</token>
<token>each</token>

i am trying to  split the string further   where it finds the ( +) and
where it finds (xxxxx) and where it finds (yyyyy)

so a substring which has a (+)  has to return with the substring just
after it as one token element
so the result that i am struggling to achieve is the following  :

<token>i</token>
<token>have</token>
<token>22</token>

<token>xxxxx</token>
<token>+10</token>

<token>elements</token>
<token>in</token>
<token>my</token>
<token>database+10</token>

<token>+10</token>
<token>yyyyyy</token>

<token>attribute</token>
<token>for</token>
<token>each</token>