Saxon » SaxonJS

For the match pattern:

P/C[position() != 1]

Saxon-EE allocates a GeneralPositionPattern and generates the SEF instructions:

  <p.withUpper role="match" axis="parent" upFirst="true">
     <p.genPos type="C">
      <vc op="ne" comp="CAVC">
       <fn name="position"/>
       <int val="1"/>
      </vc>
     </p.genPos>
     <p.nodeTest test="P" jsTest="..."/>
    </p.withUpper>

Unfortunately Saxon-JS currently doesn't support the p.genPos pattern instruction.

(When the pattern doesn't involve an upper component, e.g. C[position() != 1] optimisation avoids p.genPos and uses p.genNode with either tail() or remove() calls)