absence of a __hash metamethod

["James Shaw" <js102@...>]

I see this was discussed a couple of years back in the thread "equals
metamethod and hash functions"
http://lua-users.org/lists/lua-l/2005-06/msg00108.html.  Some
alternatives were suggested, mostly involving string building.

I'm using tables as keys for another table, and I'm re-generating the
tables when I need the keys (I don't think there's a simple way for me
to retain references to the original keys).

Coming from a Java background, I was surprised to find that there
isn't a metamethod for this in lua (unless there is and I haven't
found it, of course ;)  I can probably work around my particular
problem if I need to, but I'm more interested in knowing about the
missing __hash function.

James