how to make then __index and __newindex detect table.index

Question

I'm still a little newbie with metatables, and there is something that makes me confused

when I use metamethods like __index and __newindex in my metatable, they are only called when I invoke an element of the table as follows:

print(table[index]) -- this call the __index

table[index] = value -- this call the __newindex

but these two metamethods are not called when I invoke an element of the table as follows:

print(table.index) -- this does NOT call __index

table.index = value -- this does NOT call __newindex

my question is, is there any way to make table.index also call these two metamethods? or does only table[index] work?

Answer 1

Yes, __index will work with both brackets: mytable["index"] as well as the dot operator: mytable.index

mytable = setmetatable({}, { __index = function(t, k)
  if k == "index" then
    return "works fine"
  end
  return rawget(t, k)
end })

print(mytable["index"])
print(mytable.index)

You can circumvent the preset metatable methods using rawget and rawset

Having said that, if you are new to Lua I recommend looking for simple solutions that work WITHOUT metatables.