static int call_binTM (lua_State *L, StkId top, TMS event) {
/* try first operand */
Closure *tm = luaT_gettmbyObj(L, top-2, event);
L->top = top;
if (tm == NULL) {
tm = luaT_gettmbyObj(L, top-1, event); /* try second operand */
if (tm == NULL) {
tm = luaT_gettm(L, 0, event); /* try a `global' method */
if (tm == NULL)
return 0; /* error */
}
}
lua_pushstring(L, luaT_eventname[event]);
luaD_callTM(L, tm, 3, 1);
return 1;
}
void luaV_setglobal (lua_State *L, TString *s) {
const TObject *oldvalue = luaH_getstr(L->gt, s);
Closure *tm = luaT_gettmbyObj(L, oldvalue, TM_SETGLOBAL);
if (tm == NULL) { /* is there a tag method? */
if (oldvalue != &luaO_nilobject) {
/* cast to remove `const' is OK, because `oldvalue' != luaO_nilobject */
*(TObject *)oldvalue = *(L->top - 1);
}
else {
TObject key;
ttype(&key) = LUA_TSTRING;
tsvalue(&key) = s;
*luaH_set(L, L->gt, &key) = *(L->top - 1);
}
}
else {
luaD_checkstack(L, 3);
*(L->top+2) = *(L->top-1); /* new value */
*(L->top+1) = *oldvalue;
ttype(L->top) = LUA_TSTRING;
tsvalue(L->top) = s;
clvalue(L->top-1) = tm;
ttype(L->top-1) = LUA_TFUNCTION;
L->top += 3;
luaD_call(L, L->top - 4, 0);
}
}
/*
** Function to index a table.
** Receives the table at `t' and the key at top.
*/
const TObject *luaV_gettable (lua_State *L, StkId t) {
Closure *tm;
int tg;
if (ttype(t) == LUA_TTABLE && /* `t' is a table? */
((tg = hvalue(t)->htag) == LUA_TTABLE || /* with default tag? */
luaT_gettm(L, tg, TM_GETTABLE) == NULL)) { /* or no TM? */
/* do a primitive get */
const TObject *h = luaH_get(L, hvalue(t), L->top-1);
/* result is no nil or there is no `index' tag method? */
if (ttype(h) != LUA_TNIL || ((tm=luaT_gettm(L, tg, TM_INDEX)) == NULL))
return h; /* return result */
/* else call `index' tag method */
}
else { /* try a `gettable' tag method */
tm = luaT_gettmbyObj(L, t, TM_GETTABLE);
}
if (tm != NULL) { /* is there a tag method? */
luaD_checkstack(L, 2);
*(L->top+1) = *(L->top-1); /* key */
*L->top = *t; /* table */
clvalue(L->top-1) = tm; /* tag method */
ttype(L->top-1) = LUA_TFUNCTION;
L->top += 2;
luaD_call(L, L->top - 3, 1);
return L->top - 1; /* call result */
}
else { /* no tag method */
luaG_typeerror(L, t, "index");
return NULL; /* to avoid warnings */
}
}
const TObject *luaV_getglobal (lua_State *L, TString *s) {
const TObject *value = luaH_getstr(L->gt, s);
Closure *tm = luaT_gettmbyObj(L, value, TM_GETGLOBAL);
if (tm == NULL) /* is there a tag method? */
return value; /* default behavior */
else { /* tag method */
luaD_checkstack(L, 3);
clvalue(L->top) = tm;
ttype(L->top) = LUA_TFUNCTION;
tsvalue(L->top+1) = s; /* global name */
ttype(L->top+1) = LUA_TSTRING;
*(L->top+2) = *value;
L->top += 3;
luaD_call(L, L->top - 3, 1);
return L->top - 1;
}
}
/*
** Call a function (C or Lua). The function to be called is at *func.
** The arguments are on the stack, right after the function.
** When returns, the results are on the stack, starting at the original
** function position.
** The number of results is nResults, unless nResults=LUA_MULTRET.
*/
void luaD_call (lua_State *L, StkId func, int nResults) {
lua_Hook callhook;
StkId firstResult;
CallInfo ci;
Closure *cl;
if (ttype(func) != LUA_TFUNCTION) {
/* `func' is not a function; check the `function' tag method */
Closure *tm = luaT_gettmbyObj(L, func, TM_FUNCTION);
if (tm == NULL)
luaG_typeerror(L, func, "call");
luaD_openstack(L, func);
clvalue(func) = tm; /* tag method is the new function to be called */
ttype(func) = LUA_TFUNCTION;
}
cl = clvalue(func);
ci.func = cl;
infovalue(func) = &ci;
ttype(func) = LUA_TMARK;
callhook = L->callhook;
if (callhook)
luaD_callHook(L, func, callhook, "call");
firstResult = (cl->isC ? callCclosure(L, cl, func+1) :
luaV_execute(L, cl, func+1));
if (callhook) /* same hook that was active at entry */
luaD_callHook(L, func, callhook, "return");
LUA_ASSERT(ttype(func) == LUA_TMARK, "invalid tag");
/* move results to `func' (to erase parameters and function) */
if (nResults == LUA_MULTRET) {
while (firstResult < L->top) /* copy all results */
*func++ = *firstResult++;
L->top = func;
}
else { /* copy at most `nResults' */
for (; nResults > 0 && firstResult < L->top; nResults--)
*func++ = *firstResult++;
L->top = func;
for (; nResults > 0; nResults--) { /* if there are not enough results */
ttype(L->top) = LUA_TNIL; /* adjust the stack */
incr_top; /* must check stack space */
}
}
luaC_checkGC(L);
}
/*
** Receives table at `t', key at `key' and value at top.
*/
void luaV_settable (lua_State *L, StkId t, StkId key) {
int tg;
if (ttype(t) == LUA_TTABLE && /* `t' is a table? */
((tg = hvalue(t)->htag) == LUA_TTABLE || /* with default tag? */
luaT_gettm(L, tg, TM_SETTABLE) == NULL)) /* or no TM? */
*luaH_set(L, hvalue(t), key) = *(L->top-1); /* do a primitive set */
else { /* try a `settable' tag method */
Closure *tm = luaT_gettmbyObj(L, t, TM_SETTABLE);
if (tm != NULL) {
luaD_checkstack(L, 3);
*(L->top+2) = *(L->top-1);
*(L->top+1) = *key;
*(L->top) = *t;
clvalue(L->top-1) = tm;
ttype(L->top-1) = LUA_TFUNCTION;
L->top += 3;
luaD_call(L, L->top - 4, 0); /* call `settable' tag method */
}
else /* no tag method... */
luaG_typeerror(L, t, "index");
}
}
