Dear ken that is typing mistakes!!!

Input:
<p>a, b, <i>c</i>, <b>d</b></p>
 
Xsl:
<xsl:template match="p">
  <xsl:variable name="txt-with-node" select="."/>
  <a-g>
    <xsl:for-each select="tokenize($txt-with-node,', ')">
     <a><xsl:value-of select="."/></a>
   </a-g>
  </xsl:if>
</xsl:template>

Required output
<a-g>
     <a>a</a>
     <a>b</a>
     <a><i>c</i></a>
     <a><b>d</b></a>
   </a-g>