private Expression makeSetPredicateVariablesScript(BooleanIndexDefinition options) {
        List<Expression> expressions = new ArrayList<>();
        expressions.add(new ConstantExpression(new IntegerFieldValue(options.getArity())));
        expressions.add(new SetVarExpression("arity"));
        if (options.hasLowerBound()) {
            expressions.add(new ConstantExpression(new LongFieldValue(options.getLowerBound())));
            expressions.add(new SetVarExpression("lower_bound"));
        }
        if (options.hasUpperBound()) {
            expressions.add(new ConstantExpression(new LongFieldValue(options.getUpperBound())));
            expressions.add(new SetVarExpression("upper_bound"));
        }
        return new StatementExpression(expressions);
    }
Validates the predicate fields.

@author Lester Solbakken
config-model/src/main/java/com/yahoo/schema/processing/PredicateProcessor.java