How do I use getmetatable()?

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#1

How do I use getmetatable() ?
Been stuck on this since docs well are weird

#2

There’s a really nice meta tables and meta methods resource floating around on here. It explained a lot of it very clearly. What are metatables for and how to understand them? - #2 by BenSBk

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#3

I already know how metatables work.
Just don’t know what getmetatable() could be used for…
I mean, never saw someone using it.

#4 
local MetaTable = setmetatable({},{
     __index = function(Self, Index)
         print("Hi ".. Index) 
     end;
})

print(MetaTable.A)

Output

Hi A

getmetatable(MetaTable).__index = function(Self, Index)
     print("Now "..Index)
end;

Output

Now A

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#5

Deleted again WOOPS;

Set up metatable

local MetaTable = setmetatable({},{
     __index = function(Self, Index)
           print("Hi ".. Index)
     end;
})

print(MetaTable.A)

Output

Hi A

getmetatable( Metatable)

getmetatable(MetaTable).__index = function(Self, Index)
     print("Now ".. Index)
end;

print(MetaTable.A)

Output

Now A

#6

Useful if you do not have a reference to a table’s metatable.

Here, we do not have a direct reference to the metatable to which we must use getmetatable if we need it:

local tableWithMetatable = setmetatable({}, {__index = function() end})

Otherwise, you might not need it if you have a variable defined as it’s metatable.

#7

So basically getmetatable is dumb?

#8

It gets the table’s metatable. In practice it’s not very useful, since you probably defined the metatable yourself in the first place, and probably already have a reference to it.

#9

Essentially yes, the only case I could see is getting a script env? Or just perhaps when you lose a reference as stated by @fixmycode

local OldEnv = getfenv()
local Env = setfenv({},{
     __index = function(Self, Index)
          if OldEnv[Index] == nil then
               error("Attempted to Index nil value ".. Index)
          else
                return OldEnv[Index]
          end
})
     end;
})

getmetatable(getfenv())

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#10

Sorry. I misunderstood what you meant by “How do I use getmetatable()?” I thought you wanted a tutorial on how to use getmetable(). Didn’t realize you were asking for a use case for it. My bad.

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