How do you implement a Stack(data structure)?

A very simple stack system can be implemented using built-in Lua functions.

local function top(stack, item)
    table.insert(stack, item)
end

local function pop(stack)
    return table.remove(stack, #stack)
end

function peek(stack)
    return stack[#stack]
end

local stack = {}

top(stack, 67)

print(peek(stack))
print(pop(stack))
print(peek(stack))