Is it possible to dispatch on the arity of a function?

[pablosanjose]

Check out this thread

Finding the number of arguments of an anonymous function

I have an API wherein a kwarg is a function. function apifunc(; f::Function = identity) ... end I would like to do something different depending on the number of arguments of f, so that apifunc(f = x -> 2) calls _apifunc1(f) but apifunc(f = (x,y) -> 2) calls _apifunc2(f). Is there a way to achieve that, preferably in a non-dynamical way? In other words, is there any way to do introspection on the allowed signatures of a function’s methods?

TL;DR: isapplicable applicable is probably your best approach for this