There is one exception though, which is keyword arguments
Am Samstag, 30. Mai 2015 03:49:45 UTC+2 schrieb Steven G. Johnson:
>
> *No!* This is one of the most common misconceptions about Julia
> programming.
>
> The type declarations in function arguments have *no impact* on
> performance. Zero. Nada. Zip. You *don't have to declare a type at
> all* in the function argument, and it *still* won't matter for
> performance.
>
> The argument types are just a filter for when the function is applicable.
>
> The first time a function is called, a specialized version is compiled for
> the types of the arguments that you pass it. Subsequently, when you call
> it with arguments of the same type, the specialized version is called.
>
> Note also that a default argument foo(x, y=false) is exactly equivalent to
> defining
>
> foo(x,y) = ...
> foo(x) = foo(x, false)
>
> So, if you call foo(x, [1,2,3]), it calls a version of foo(x,y)
> specialized for an Array{Int} in the second argument. The existence of a
> version of foo specialized for a boolean y is irrelevant.
>
