Re: Strange meta __newindex behavior

[David Haley <dchaley@...>]

On this day of 03/24/07 23:28, Alan Hightower saw fit to scribe:
> 
> No, the second case is independent of the first.  When I perform
> root.sub1.foo = bar, sub1 doesn't exist in the root yet.  After the line
> executes, it does, yet I never get called for the new index add.  This
> seems broken to me.

Then something is missing from the story:

---------8<------------8<------------8<-------------------------
$ cat test.lua


root = {}
root._hidden_vals = {}
root._my_meta = {}
root._my_meta.__index = root._hidden_vals
root._my_meta.__newindex = _proc_lua_assignment

root._hidden_vals = function () print "index" end
root._proc_lua_assignment = function () print "newindex" end

setmetatable (root, root._my_meta)

root.sub1.foo = "bar"
---------8<------------8<------------8<-------------------------
$ lua test.lua
lua: test.lua:16: attempt to index field 'sub1' (a nil value)
stack traceback:
        test.lua:16: in main chunk
        [C]: ?
---------8<------------8<------------8<-------------------------

You have to have created the sub1 table first, before being able to
index sub1.foo. Otherwise, as we see here, sub1 is nil.

Cheers,
- David


-- 
~David-Haley
http://david.the-haleys.org