have there ever been any successful "skinnable" languages (or any successful language skins)? i'm thinking of things like SPECS for C++, or the way research fun

have there ever been any successful "skinnable" languages (or any successful language skins)? i'm thinking of things like SPECS for C++, or the way research functional languages sometimes provide both, e.g., a C-ish and a lisp-ish syntax that compile to the same thing.