> It can also simply return control, without returning anything. It's equivalent to invoking a continuation with zero arguments. Do you allow for zero-argument

> It can also simply return control, without returning anything. It's equivalent to invoking a continuation with zero arguments. Do you allow for zero-argument functions, at least? There's nothing weird about a function taking 0 arguments, any more than there's anything weird about a function taking 3 or 5 arguments. A function can't take an argument of type void, so functions shouldn't be allowed to return void either. > Of course, if a function can't return no value whatsoever, you suddenly need new syntactical categories to support it: you need to prohibit using such functions in an expressions (only call statements are allowed), you need a way to return from such a function (naked "return", which is prohibited from taking any expressions), and it's also severely strains your generics/templates because you can't treat such functions uniformly etc. Or you do what sensible languages do: all functions return a value (if they return at all), functions that don't want to return anything in particular can return a unit value but that value is just a normal value that behaves normally in expressions etc., you don't make naked return a special case (you can make it syntax sugar for "return unit" if you really want), and you can treat those functions uniformly in generics, much more easily than with C++ templates where you have to make special cases for void functions.