Re: Lua design : why no lists ?

[Rici Lake <lua@...>]

On 16-Sep-04, at 11:38 AM, Mark Hamburg wrote:

> What Lua doesn't support as efficiently are sets where there are a 
> number of
> keys to hash but the values are all "true".

In many cases where there are a large number of such sets, all these 
sets share a single key domain (universe). (Option sets, for example, 
or state sets). In this case, you can create a Universe table which 
maps keys to integers and vice versa (assuming the keys cannot be 
integers, otherwise you need two tables), and implement the set itself 
as a long bit-vector; the only Lua object which needs to be referenced 
is the universe itself.