I don't think pattern matching is necessary for ADTs. It's useful, but you could have e.g. > if MyType.ConstructorA(a): > ... > elif MyType.ConstructorB(

I don't think pattern matching is necessary for ADTs. It's useful, but you could have e.g. > if MyType.ConstructorA(a): > ... > elif MyType.ConstructorB(a): > ... or even something like > with MyType.ConstructorA(a) as b, c: > ... > else with MyType.ConstructB(a) as d: > ... a "with/else with" construct would be a fairly straightforward addition to Python's "context manager" interface.