1. A method implemented by one or more computing devices, the method comprising: checking compatibility of a second collection of dynamically-typed executable machine-readable code with a first collection of statically-typed executable machine-readable code, the checking comprising: parsing the first collection of statically-typed executable machine-readable code to locate descriptions of one or more application programming interfaces (APIs) included in the first collection of statically-typed executable machine-readable code; projecting the descriptions of the one or more application programming interfaces of the first collection of statically-typed executable machine-readable code into an alternate form; and employing the projected descriptions of the first collection of statically-typed executable machine-readable code to check for the compatibility of the second collection of dynamically-typed executable machine-readable code with the first collection of statically-typed executable machine-readable code.