[notjack]

> Whether these restricted languages are doable as embedded DSLs in general-purpose language remains to be seen

I'd argue that the Racket language (or language platform, depending on your view of things) shows it's possible with its #lang mechanism and macro system. For example, though Racket proper is untyped, Typed Racket is implemented as a #lang with macros and includes an optimizing compiler that removes runtime checks on programs that typecheck successfully.