How to do memoization or memoisation in Julia 1.0

Question

I have been trying to do memorisation in Julia for the Fibonacci function. This is what I came up with.

The original unmodified code (for control purposes)

Answer 1

The simplest way to do it is to use get!

const fibmem = Dict{Int,Int}()
function fib(n)
    get!(fibmem, n) do
        n < 3 ? 1 : fib(n-1) + fib(n-2)
    end
end

Note the const specifier outside fibmem. This avoids the need for global, and will make the code faster as it allows the compiler to use type inference within fib.