wichtel.jl

import Random

function generate_pairs(names)
    while true
        candidates = zip(names, Random.shuffle(names)) |> collect
        
        # Only take those permutations without fixed point, i.e.
        # noone has to buy a present for herself/himself
        if findfirst(p -> p[1] == p[2], candidates) === nothing
            return candidates
        end
    end
end

function print_present_giving(pairs)
    for p in pairs
        println("$(p[1]) beschenkt $(p[2])")
    end
end

# Place your real friends here
names = ["person1", "person2", "person3"]

# Now print who has to buy presents for whom
names |> generate_pairs |> print_present_giving