A method for extending functionality of a compiler includes: receiving a first source file written in a language that supports multiple system types, wherein the first source file includes a plurality of source constructs associated with parameter types of the multiple type systems; annotating each of the plurality of source constructs with the type system from one of the multiple type systems and precise parameter type to which its associated type system belongs; retrieving type system rules corresponding to each type system referred to in the first source file from a type system loader; verifying, using the type system rules, that instances of use of variables, expressions, and methods in the first source file are appropriate with respect to the type system of annotated types associated with the source constructs; and compiling the first source file to produce a second source file including type information retained from the first source file.