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On 27 January 2011 21:36, Steve Litt <> wrote:
> On Thursday 27 January 2011 15:18:28 Javier Guerra Giraldez wrote:
>> On Thu, Jan 27, 2011 at 3:09 PM, Steve Litt <>
> wrote:
>> > Steve, you just lost me. I thought __index is the function that gets done
>> > when you write-access a key in the table. But A is the whole table, not a
>> > function. What am I missing?
>> __index can be a function or a table.
>> a common idiom is to use the same metatable as __index; so you put
>> there both the metamethods (__xxx) and OO-style methods
> I'll have to do more reading on metatables, and keep in mind that__index can
> be a function OR a table.

Reading Programming in Lua by Roberto Ierusalimschy
( is VERY recommended. It is very
friendly/easy reading, and explains all main ideas and idioms in Lua.
For example, the chapter 13.4.1 (The __index Metamethod, states the following:

The use of the __index metamethod for inheritance is so common that
Lua provides a shortcut. Despite the name, the __index metamethod does
not need to be a function: It can be a table, instead. When it is a
function, Lua calls it with the table and the absent key as its
arguments. When it is a table, Lua redoes the access in that table.