Re: "nesting" metatables

[Philipp Janda <siffiejoe@...>]

Am 31.12.2015 um 12:41 schröbte Dirk Laurie:
> 2015-12-31 10:34 GMT+02:00 Marc Balmer <marc@msys.ch>:
>
> > When a nested __index metamethod is being called, does
> > it still get the original table as the first argument, or the table
> > that caused this __index metamethod to be called (i.e. the
> > previously indexed table)?

It's a dozen lines of Lua code to figure this out, and it would have 
prevented a lot of confusion:

    local mt = {
      __index = setmetatable( {}, {
        __index = function( o, k )
          print( o, k )
        end
      } )
    }
    local t = setmetatable( {}, mt )

    print( "t", t )
    print( "mt.__index", mt.__index )
    local dummy = t.x

Typical output:

    t	table: 0x1d16060
    mt.__index	table: 0x1d16530
    table: 0x1d16530	x

> It's a tail call. I.e. all that happens is that exactly the same
> stack is presented to the new function. Since the original
> table was the first argument, it still is.

If I understand the question correctly, this is wrong. See above.

Philipp