Depending on how much performance you need, you could do something like:
_f(a::A, b::B, c::C) = ...
function f(args...)
a,b,c = A(1),B(1),C(1)
for arg in args
T = typeof(arg)
if T <: A
a = arg
elseif T <: B
b = arg
elseif T <: C
c = arg
end
end
_f(a,b,c)
end
And if you need to do this in multiple places, I'm sure you could turn this
into a macro fairly easily.
On Thu, Jan 7, 2016 at 2:02 PM, Josh Day <[email protected]> wrote:
> Suppose I have a function that takes several arguments of different types
> and each has a default value. What is the best way to specify all possible
> methods where a user can specify an argument without entering the defaults
> that come before it? I don't want to force a user to remember the exact
> order of arguments. The example below may explain this better.
>
> type A
> a::Int
> end
> type B
> b::Int
> end
> type C
> c::Int
> end
> f(a::A = A(1), b::B = B(1), c::C = C(1)) = ...
>
> I would like the user to be able to call f(C(3), B(2))instead of f(A(1),
> B(2), C(3)). I could just implement the factorial(3)methods myself, but
> if I want to do this for 5 types, it means I'm writing 120 methods.
>
> Is this just a terrible idea and I should use keyword arguments?
>
