I Have been browsed on the internet to find an explanation for this problem for 3 days, But I didn't get an explanation to solve this problem. Anyways, I can't solve why "gaming.child.p" return 0 instead of 11. I will be very grateful for your explanation.

Here's the code :

local X = {
    
    p = 1,
    diffElementPls = "man"

}; 

local Y = {__index = X}; 

function interface() 
    
    local o = {}; 
    return setmetatable(o, Y); 
    
end 


local w = {
    
    something = "u found me",
    child = interface()
    
}; 

local noob = {__index = w}; 

function new() 
    
    local o = {}; 
    return setmetatable(o, noob); 
    
end

local gaming = new();
local wd = new()

gaming.something = "noob"
gaming.child.p  = 10

wd.child.p = 0


print(gaming.something, wd.something, gaming.child.p, wd.child.p) -- print noob u found me 0 0 instead of noob u found me 11 0

CodePudding user response：

gaming.child and wd.child refer to the same table.

hence modifying wd.child.p also changes the value of gaming.child.p as it is the same variable.

Both wd and gaming don't have a field child. Hence when you index it Lua will refer to their metatable w. So in both cases you're actually modifing w.child.p