Looks great - unlike java which is somehow recommending the format:

STR."Hello \{this.user.firstname()}, how are you?\nIt's \{tempC}°C today!"

compared to scala

s"Hello ${this.user.firstname()}, how are you?\nIt's ${tempC}°C today!"

STR."" ? really?

Yeah, I hate to bikeshed, but this is the worst syntax possible without being a full-out prank.

also a syntax for braces that looks like escaping