final RippleList rest = stack.getRest();
Sink<RippleList> listSink = new Sink<RippleList>() {
public void put(RippleList list) throws RippleException {
if (i < 1) {
throw new RippleException("list index out of bounds" +
" (keep in mind that 'at' begins counting at 1): " + i);
}
for (int j = 1; j < i; j++) {
list = list.getRest();
if (list.isNil()) {
throw new RippleException("list index out of bounds: " + i);
}
}
solutions.put(
rest.push(list.getFirst()));