Julia: Understanding Multiple dispatch for OOP - oop

Question

Lets say I have the following types:
type cat
cry:: String
legs:: Int
fur:: String
end
type car
noise::String
wheels::Int
speed::Int
end
Lion = cat("meow", 4, "fuzzy")
vw = car("honk", 4, 45)
And I want to add a method describe to both of them which prints the data inside them. Is it best to use methods to do it this way:
describe(a::cat) = println("Type: Cat"), println("Cry:", a.cry, " Legs:",a.legs, " fur:", a.fur);
describe(a::car) = println("Type: Car"), println("Noise:", a.noise, " Wheels:", a.wheels, " Speed:", a.speed)
describe(Lion)
describe(vw)
Output:
Type: Cat
Cry:meow Legs:4 fur:fuzzy
Type: Car
Noise:honk Wheels:4 Speed:45
Or should I use a function like in this question I posted before: Julia: What is the best way to set up a OOP model for a library
Which method is more efficient?
Most Methods examples in the documentation are simple functions, if I wanted a more complex Method with loops or if statements are they possible?

Answer 1

First of all, I recommend using a capital letter as the first letter of a type name - this is an extremely consistent thing in Julia style, so not doing it would definitely be awkward for people using your code.
As you are doing multi-statement methods, you should probably write them as full functions, e.g.
function describe(a::cat)
println("Type: Cat")
println("Cry:", a.cry, " Legs:", a.legs, " fur:", a.fur)
end
function describe(a::car)
println("Type: Car")
println("Noise:", a.noise, " Wheels:", a.wheels, " Speed:", a.speed)
end
Typically the one-liner version is used only for simple single statements.
May also be worth noting that we are making one function, with two methods, in case that wasn't clear from the manual.
Finally, you could also add a method to the base Julia print function, e.g.
function Base.print(io::IO, a::cat)
println(io, "Type: Cat")
print(io, "Cry:", a.cry, " Legs:", a.legs, " fur:", a.fur)
end
function Base.print(io::IO, a::car)
println(io, "Type: Car")
print(io, "Noise:", a.noise, " Wheels:", a.wheels, " Speed:", a.speed)
end
(if you call println, it'll call print internally and add the \n automatically)