local function add(a, b)
    return a + b
end

local function greet(name)
    print("Hello, " .. name .. "!")
end

local Person = {}
Person.__index = Person

function Person:new(id, name, email)
    local obj = {
        id = id,
        name = name,
        email = email
    }
    setmetatable(obj, self)
    return obj
end

function Person:__tostring()
    return self.name .. " <" .. self.email .. ">"
end

local Repository = {}
Repository.__index = Repository

function Repository:new()
    return setmetatable({items = {}}, self)
end

function Repository:add(key, item)
    self.items[key] = item
end

function Repository:find(key)
    return self.items[key]
end

function Repository:getAll()
    local result = {}
    for _, v in pairs(self.items) do
        table.insert(result, v)
    end
    return result
end

local repo = Repository:new()
repo:add(1, Person:new(1, "Alice", "alice@example.com"))
repo:add(2, Person:new(2, "Bob", "bob@example.com"))

for _, p in ipairs(repo:getAll()) do
    print(p)
end

print("3 + 4 = " .. add(3, 4))