Metatables in Lua

 Metatables in Lua

Metatables in Lua allow you to define custom behavior for tables, such as how they are indexed or how they behave in mathematical operations. Here's an example:

local t = {}

local mt = {

  __index = function(t, k)

if k == "hello" then

return "world"

else

return nil

end

end,

__add = function(t1, t2)

local result = {}

for i = 1, #t1 do

result[i] = t1[i] + t2[i]

end

return result

end

}

setmetatable(t, mt)

print(t.hello)

print(t.foo)

local t1 = {1, 2, 3}

local t2 = {4, 5, 6}

local t3 = t1 + t2

for i = 1, #t3 do

print(t3[i])

end