Sounds similar to how Haskell does all number computations by default. When you do 1/3 for example it leaves the types generic/ambiguous using typeclasses until it finds something to refine them. 1/3 could be a floating-point number, or a fixed-point number, or a rational (datatype holding the numerator and denominator), or any other user-defined datatype. You could put these computations in a library, keeping their types generic with typeclasses, and a user of your library can use their own number datatypes. Your library would automatically support that datatype in your number computations.