Re: Weak keyed tables with primitive keys

["Cheng, Long" <long.x.cheng@...>]

From my opinion, implement a data cache using weak table is not a good 
idea. If you do so, your application will have no control over when the 
data in cache will be garbage collected. Even if the data is access very 
frequently by clients, it may still be collected immediately after all 
references are released. You should implement the cache in a regular 
table and implement a replacement algorithm to manage the data in cache.

Regards
Long

Mark Hamburg 写道:
> I understand the theoretical arguments for treating strings as values 
> with respect to weak tables, but are there any practical benefits? It 
> would seem, for example, to get in the way of caching the results of 
> file reads a la:
>
> fileCache = setmetatable( { }, {
> __mode = 'kv',
> __index = function( t, k )
> local v
> local f = io.open( k )
> if f then
> v = f:read( "*a" )
> t[ k ] = v
> f:close()
> end
> return v
> end } )
>
> Mark