// ES5 8.10.5 ToPropertyDescriptor
static bool toPropertyDescriptor(ExecState* exec, JSValue in, PropertyDescriptor& desc)
{
    if (!in.isObject()) {
        throwError(exec, createTypeError(exec, ASCIILiteral("Property description must be an object.")));
        return false;
    }
    JSObject* description = asObject(in);

    PropertySlot enumerableSlot(description);
    if (description->getPropertySlot(exec, exec->propertyNames().enumerable, enumerableSlot)) {
        desc.setEnumerable(enumerableSlot.getValue(exec, exec->propertyNames().enumerable).toBoolean(exec));
        if (exec->hadException())
            return false;
    }

    PropertySlot configurableSlot(description);
    if (description->getPropertySlot(exec, exec->propertyNames().configurable, configurableSlot)) {
        desc.setConfigurable(configurableSlot.getValue(exec, exec->propertyNames().configurable).toBoolean(exec));
        if (exec->hadException())
            return false;
    }

    JSValue value;
    PropertySlot valueSlot(description);
    if (description->getPropertySlot(exec, exec->propertyNames().value, valueSlot)) {
        desc.setValue(valueSlot.getValue(exec, exec->propertyNames().value));
        if (exec->hadException())
            return false;
    }

    PropertySlot writableSlot(description);
    if (description->getPropertySlot(exec, exec->propertyNames().writable, writableSlot)) {
        desc.setWritable(writableSlot.getValue(exec, exec->propertyNames().writable).toBoolean(exec));
        if (exec->hadException())
            return false;
    }

    PropertySlot getSlot(description);
    if (description->getPropertySlot(exec, exec->propertyNames().get, getSlot)) {
        JSValue get = getSlot.getValue(exec, exec->propertyNames().get);
        if (exec->hadException())
            return false;
        if (!get.isUndefined()) {
            CallData callData;
            if (getCallData(get, callData) == CallTypeNone) {
                throwError(exec, createTypeError(exec, ASCIILiteral("Getter must be a function.")));
                return false;
            }
        }
        desc.setGetter(get);
    }

    PropertySlot setSlot(description);
    if (description->getPropertySlot(exec, exec->propertyNames().set, setSlot)) {
        JSValue set = setSlot.getValue(exec, exec->propertyNames().set);
        if (exec->hadException())
            return false;
        if (!set.isUndefined()) {
            CallData callData;
            if (getCallData(set, callData) == CallTypeNone) {
                throwError(exec, createTypeError(exec, ASCIILiteral("Setter must be a function.")));
                return false;
            }
        }
        desc.setSetter(set);
    }

    if (!desc.isAccessorDescriptor())
        return true;

    if (desc.value()) {
        throwError(exec, createTypeError(exec, ASCIILiteral("Invalid property.  'value' present on property with getter or setter.")));
        return false;
    }

    if (desc.writablePresent()) {
        throwError(exec, createTypeError(exec, ASCIILiteral("Invalid property.  'writable' present on property with getter or setter.")));
        return false;
    }
    return true;
}