Method mergedAxis

basex-core/src/main/java/org/basex/query/expr/path/Path.java:1098–1107

Returns a merged axis for a step preceded by a descendant-or-self step. @param expr step to test @return axis or null

(final Expr expr)

   * @return axis or {@code null}
   */
  private static Axis mergedAxis(final Expr expr) {
    if(expr instanceof final Step step) {
      final Axis axis = step.axis;
      if(!step.mayBePositional()) {
        if(axis == CHILD || axis == DESCENDANT) return DESCENDANT;
        if(axis == DESCENDANT_OR_SELF) return DESCENDANT_OR_SELF;
      }
    }
    return null;
  }

  /**
   * Returns the common merged axis of multiple expressions.