Can you please tell me what's wrong with this code?

Question

Here's some Lua code I just wrote in SCIte, and I don't know what's wrong with it exactly, so could someone explain to me what I did wrong and how to fix it?

t = setmetatable({},{
__newindex = function(t, key)
if key == false then
  return( "False cannot exist in table")
  key = nil
  end
if key == __string then
  table.concat[table, key]
else
  table[key] = nil
  end
if key == nil then
  return  "Tables in this file cannot contain false values."
end
}
)

function Error()
  _,cError = pcall(__index)
end
function Call1()
  error("error in metatable function, '__index'", 1)
end
function Call2()
  Call1()
end

Error()

Call2()

Answer 1

There are many things wrong with it, so many it's almost impossible to amend. However these fixes may help you, I've tried to fix your function here based on what you had before. I suggest you learn more about the language before attempting to create classes with metatables.

t = setmetatable({},{
    __newindex = function(t, key)
        if key == false then
          return( "False cannot exist in table") -- return values in this function don't make sense
          --key = nil THIS WILL NEVER BE REACHER
        end
        if type(key) == "string" then --check key is a string
          table[key] = {}
        else
          table[key] = nil 
        end
        if key == nil then
          return  "Tables in this file cannot contain false values."
        end
    end
    }
)

Further

function Call1()
  error("error in metatable function, '__index'", 1)
end

Is nonsensical, it will always output an error, i.e:

error("No error here")

Will produce

lua: ex.lua:26: No error here