I use preprocessor functions, (currently) all of which take string arguments. preprocessorV2 now requires quotes around strings, which I find too verbose for my use case. So I use !unquoted and it works as expected:
!unquoted function $CALL_METHOD($FROM_CLASS, $TO_CLASS, $FUNC_NAME, $ARG = "", $RETURN_LABEL = "")
$FROM_CLASS -> $TO_CLASS: $FUNC_NAME($ARG)
$FROM_CLASS <-- $TO_CLASS: $RETURN_LABEL
Can be used as: $CALL_METHOD(Concierge, Concierge, doThis, without //quotes//)
Even spaces in arguments are no issue. That's all great!
However, why are quotes required by default?
And what issues may arise when using !unquoted? The docs at http://wiki.plantuml.net/site/preprocessing-v2
describe but don't explain..