/**
* Evaluate exists and forAll expressions. The array <code>moreElemVars</code> may be null if
* there is at most one element variable declared.
*/
protected final Value evalExistsOrForAll(EvalContext ctx, boolean doExists) {
// evaluate range
Value v = fRangeExp.eval(ctx);
if (v.isUndefined()) return UndefinedValue.instance;
CollectionValue rangeVal = (CollectionValue) v;
// we need recursion for the permutation of assignments of
// range values to all element variables.
boolean res = evalExistsOrForAll0(0, rangeVal, ctx, doExists);
return BooleanValue.get(res);
}
