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/*
** $Id: ltm.c,v 1.2 2004/03/23 05:09:14 jbj Exp $
** Tag methods
** See Copyright Notice in lua.h
*/
#include <string.h>
#define ltm_c
#include "lua.h"
#include "lobject.h"
#include "lstate.h"
#include "lstring.h"
#include "ltable.h"
#include "ltm.h"
/*@observer@*/
const char *const luaT_typenames[] = {
"nil", "boolean", "userdata", "number",
"string", "table", "function", "userdata", "thread"
};
void luaT_init (lua_State *L) {
/*@observer@*/
static const char *const luaT_eventname[] = { /* ORDER TM */
"__index", "__newindex",
"__gc", "__mode", "__eq",
"__add", "__sub", "__mul", "__div",
"__pow", "__unm", "__lt", "__le",
"__concat", "__call"
};
int i;
for (i=0; i<TM_N; i++) {
G(L)->tmname[i] = luaS_new(L, luaT_eventname[i]);
luaS_fix(G(L)->tmname[i]); /* never collect these names */
}
}
/*
** function to be used with macro "fasttm": optimized for absence of
** tag methods
*/
const TObject *luaT_gettm (Table *events, TMS event, TString *ename) {
const TObject *tm = luaH_getstr(events, ename);
lua_assert(event <= TM_EQ);
if (ttisnil(tm)) { /* no tag method? */
events->flags |= cast(lu_byte, 1u<<event); /* cache this fact */
return NULL;
}
else return tm;
}
const TObject *luaT_gettmbyobj (lua_State *L, const TObject *o, TMS event)
{
TString *ename = G(L)->tmname[event];
switch (ttype(o)) {
case LUA_TTABLE:
return luaH_getstr(hvalue(o)->metatable, ename);
case LUA_TUSERDATA:
return luaH_getstr(uvalue(o)->uv.metatable, ename);
default:
return &luaO_nilobject;
}
}
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