I came across this thread, and although it is answered would just like to comment that I've experienced the exact opposite requirement when working with the browser-based calculation view tool on HANA Cloud Platform. Here, when working with input parameters, the expression builder does NOT insert any single quotes (example: $$IP_DATE$$), however the view will fail to activate without adding them.
So, to recap, some inconsistent behaviour on the HANA side - at least depending on tool/scenario.
Regards,
Trond