Am 03.12.2018 um 02:06 schrieb Kenneth:
> That 'png' is a keyword (or sort of like one), and I could never figure out a> way to get a string construction to 'create' a POV-Ray keyword. I assume it> can't be done-- but it would be an interesting feature to add in the future (if> possible!) ;-)
See `Parse_String` macro in `strings.inc`.