Naturally by "sum types" I mean "sum types plus the associated language-level conveniences that make them reasonable to work with". Perhaps case statements may

Naturally by "sum types" I mean "sum types plus the associated language-level conveniences that make them reasonable to work with". Perhaps case statements may be enough. Perhaps arbitrary lambdas are needed. Anyway, they're not reasonable to work with in Python. I'm not particularly familiar with C++ but I doubt they're reasonable to work with in that language either.