/**
* Checks if the path can be rewritten for iterative evaluation.
*
* @param root root expression; can be a {@code null} reference
* @param steps path steps
* @return result of check
*/
private static boolean iterative(final Expr root, final Expr... steps) {
if (root == null || !root.iterable()) return false;
final int sl = steps.length;
for (int s = 0; s < sl; ++s) {
switch (((Step) steps[s]).axis) {
// reverse axes - don't iterate
case ANC:
case ANCORSELF:
case PREC:
case PRECSIBL:
return false;
// multiple, unsorted results - only iterate at last step,
// or if last step uses attribute axis
case DESC:
case DESCORSELF:
case FOLL:
case FOLLSIBL:
return s + 1 == sl || s + 2 == sl && ((Step) steps[s + 1]).axis == Axis.ATTR;
// allow iteration for CHILD, ATTR, PARENT and SELF axes
default:
}
}
return true;
}
