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- Subject: Re: Possible enhancements for Lua 5.2
- From: Andre Leiradella <andre@...>
- Date: Sat, 25 Jun 2011 22:46:59 -0300
On 25/06/2011 22:37, Wesley Smith wrote:
I'd generate the hashes with a command-line tool ( lua_pushstring(...);
lua_tohstring(...); ) and put them into the source code, just like I do now.
const char* lua_tohstring( lua_State *L, int index, unsigned int *hash );
When writing bindings I usually get the key string in __index/__newindex
metamethods and compute some hash with them which then I use in a switch. It
would be nice if I could save the time spent in computing this hash since
Lua already has one.
How could you use the hash in a switch statement if the hash result
isn't a compile-time calculation?
static int index( lua_State* L )
unsigned int hash;
const char* key = lua_tohstring( L, 1, &hash );
if ( key == NULL )
return luaL_error( L, "key is not a string" );
switch ( hash )
case 0x12345678: /* pre-computed hash */
case 0x87654321: /* pre-computed hash */
return luaL_error( L, "invalid key: %s", key );