Revert prior attempted optimisation. Gridding the land pays in some situations, but not all. Restricting to an upper bound might help, but overall, seems too fuzzy to be worth it. On one side is increased cost of Add/Delete + extra test on collision check, on the other is skipping the list iteration. Perhaps for large lists.
/*
** $Id: lfunc.h,v 2.4.1.1 2007/12/27 13:02:25 roberto Exp $
** Auxiliary functions to manipulate prototypes and closures
** See Copyright Notice in lua.h
*/
#ifndef lfunc_h
#define lfunc_h
#include "lobject.h"
#define sizeCclosure(n) (cast(int, sizeof(CClosure)) + \
cast(int, sizeof(TValue)*((n)-1)))
#define sizeLclosure(n) (cast(int, sizeof(LClosure)) + \
cast(int, sizeof(TValue *)*((n)-1)))
LUAI_FUNC Proto *luaF_newproto (lua_State *L);
LUAI_FUNC Closure *luaF_newCclosure (lua_State *L, int nelems, Table *e);
LUAI_FUNC Closure *luaF_newLclosure (lua_State *L, int nelems, Table *e);
LUAI_FUNC UpVal *luaF_newupval (lua_State *L);
LUAI_FUNC UpVal *luaF_findupval (lua_State *L, StkId level);
LUAI_FUNC void luaF_close (lua_State *L, StkId level);
LUAI_FUNC void luaF_freeproto (lua_State *L, Proto *f);
LUAI_FUNC void luaF_freeclosure (lua_State *L, Closure *c);
LUAI_FUNC void luaF_freeupval (lua_State *L, UpVal *uv);
LUAI_FUNC const char *luaF_getlocalname (const Proto *func, int local_number,
int pc);
#endif