ServingXML

You can't read fields right to left, but you can read the entire line as a single field, and use the XSLT fn:ends-with function to test the end of the line. So, add the prefix declaration

xmlns:fn="http://www.w3.org/2005/xpath-functions"

in the sx:resources element, and use something like

  <sx:flatRecordTypeChoice>
    <sx:delimitedField name="line"/>
    <sx:when test="fn:ends-with(line,'Cap')">
      <sx:flatRecordType name='Cap'>
        <sx:fieldDelimiter value="|"/>
        <sx:delimitedField name="tradeId"/>
        <sx:delimitedField name="placeholder1"/>
        <sx:delimitedField name="currency"/>
        <sx:delimitedField name="buySell"/>
        <sx:delimitedField name="maturityDate"/>
        <sx:delimitedField name="strike"/>
        <sx:delimitedField name="recordType"/>
      </sx:flatRecordType>
    </sx:when>
    <sx:when test="fn:ends-with(line,'SWAP')">
      <sx:flatRecordType name='SwapFloatingLeg'>
        <sx:fieldDelimiter value="|"/>
        <sx:delimitedField name="tradeId"/>
        <sx:delimitedField name="style"/>
        <sx:delimitedField name="side"/>
        <sx:delimitedField name="currency"/>
        <sx:delimitedField name="index"/>
        <sx:delimitedField name="maturityDate"/>
        <sx:delimitedField name="notional"/>
        <sx:delimitedField name="recordType"/>
      </sx:flatRecordType>
    </sx:when>
  </sx:flatRecordTypeChoice>

Note that the default field delimiter is the record delimiter, so the delimiter for the field "line" is the record delimiter, as no other is specified at that level.

-- Daniel