Building apps has always required melding together disparate technologies, and that's especially true in the current mobile/web environment. Wyvern is a prototype programming language that aims to enable type-specific languages, so you can create user-defined types with new syntax.
Wyvern is attracting attention this week because the project is funded by the US National Security Agency (NSA). As an open source project, it's hard to see how a backdoor could be embedded in the language, but that's unlikely to stop the speculation.
Wyvern's approach should make it easier to extend language functionality without the risk of unexpected code execution, as some of its developers explain in a research paper:
Allowing library providers to modularly extend a language with new syntax could help address these issues. Unfortunately, prior mechanisms either limit expressiveness or are not safely composable: individually unambiguous extensions can still cause ambiguities when used together. We introduce type-speciﬁc languages (TSLs): logic associated with a type that determines how the bodies of generic literals, able to contain arbitrary syntax, are parsed and elaborated, hygienically. The TSL for a type is invoked only when a literal appears where a term of that type is expected, guaranteeing noninterference.
Of course, it's one thing to develop a language concept, and another to encourage widespread uptake. If history is any guide, risky pragmatism will dominate over a technically elegant solution.