Check if parameter of function is a function

I have a function

function f(a)
   do something that depends on a
end

which behaviour depends on the parameter a. This can be a string, an int or a function it self. For this, I want to check if the parameter is a function itself.

function f(a)
   if typeof(a) == int
      ...
   end
   ...
end

I tried to use typeof(a). If a is a function, I get

typeof(a) (singleton type of function a, subtype of Function)

but if I then use

typeof(a) == Function

it is false.

>Solution :

You can use isa() for this. A simple example:

julia> f(x) = x
f (generic function with 1 method)

julia> isa(f, Function)
true

isa can also be used as an infix operator:

julia> f isa Function
true