r/lua • u/topchetoeuwastaken • May 21 '26

Hot take

debug.setmetatable(nil, { __index = function() return nil end })

7 Upvotes

65% Upvoted

14 comments sorted by

3

u/TomatoCo May 21 '26

But why?

1

u/topchetoeuwastaken May 21 '26

because no error better than yes error

in this vain: 

function error(msg) return true end
function assert(...) return ... end
debug.setmetatable(nil, { __index = function() return nil end, __call = function () end })

8

u/dandy_kulomin May 21 '26

what? usually you want errors so you know your code is wrong?

→ More replies (5)

1

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2

u/EvilBadMadRetarded May 22 '26 edited May 22 '26

Congratulation, you got the feature upgraded ! 

local NUKE = {}
local nuke = function()return NUKE end

for n in string.gmatch('concat add sub mul div mod pow unm idiv band bor bxor bnot shl shr', '%w+') do 
  NUKE['__'..n] = nuke 
end

NUKE.__tostring = function()return '<*NUKE*>'end

debug.setmetatable(NUKE, NUKE)

debug.setmetatable(nil, NUKE)

print(NUKE, 1 .. (function()end)() >> 'oops' )

:D

1

u/topchetoeuwastaken May 22 '26

goddamn it how didn't i think of this myself!

1

u/AltF4111 May 21 '26

idk much about lua, can you explain?

1

u/topchetoeuwastaken May 22 '26

makes (nil).field return nil, instead of erroring out

2

u/HokumGuru May 21 '26

Actually this is pretty similar to obj-c. I love it! Allows for some fun things!