/*
** Function to index a table.
** Receives the table at top-2 and the index at top-1.
*/
void luaV_gettable (void)
{
struct Stack *S = &L->stack;
TObject *im;
if (ttype(S->top-2) != LUA_T_ARRAY) /* not a table, get "gettable" method */
im = luaT_getimbyObj(S->top-2, IM_GETTABLE);
else { /* object is a table... */
int32 tg = (S->top-2)->value.a->htag;
im = luaT_getim(tg, IM_GETTABLE);
if (ttype(im) == LUA_T_NIL) { /* and does not have a "gettable" method */
TObject *h = luaH_get(avalue(S->top-2), S->top-1);
if (h != NULL && ttype(h) != LUA_T_NIL) {
--S->top;
*(S->top-1) = *h;
}
else if (ttype(im=luaT_getim(tg, IM_INDEX)) != LUA_T_NIL)
luaD_callTM(im, 2, 1);
else {
--S->top;
ttype(S->top-1) = LUA_T_NIL;
}
return;
}
/* else it has a "gettable" method, go through to next command */
}
/* object is not a table, or it has a "gettable" method */
if (ttype(im) != LUA_T_NIL)
luaD_callTM(im, 2, 1);
else
lua_error("indexed expression not a table");
}
void luaT_setfallback() {
static const char *oldnames [] = { "error", "getglobal", "arith", "order", NULL };
TObject oldfunc;
lua_CFunction replace;
if (!tmFBAdded) {
luaL_addlibtolist(tmFB, (sizeof(tmFB) / sizeof(tmFB[0])));
tmFBAdded = true;
}
const char *name = luaL_check_string(1);
lua_Object func = lua_getparam(2);
luaL_arg_check(lua_isfunction(func), 2, "function expected");
switch (luaO_findstring(name, oldnames)) {
case 0: // old error fallback
oldfunc = errorim;
errorim = *luaA_Address(func);
replace = errorFB;
break;
case 1: // old getglobal fallback
oldfunc = *luaT_getim(LUA_T_NIL, IM_GETGLOBAL);
*luaT_getim(LUA_T_NIL, IM_GETGLOBAL) = *luaA_Address(func);
replace = nilFB;
break;
case 2:
{ // old arith fallback
int32 i;
oldfunc = *luaT_getim(LUA_T_NUMBER, IM_POW);
for (i = IM_ADD; i <= IM_UNM; i++) // ORDER IM
fillvalids(i, luaA_Address(func));
replace = typeFB;
break;
}
case 3:
{ // old order fallback
int32 i;
oldfunc = *luaT_getim(LUA_T_NIL, IM_LT);
for (i = IM_LT; i <= IM_GE; i++) // ORDER IM
fillvalids(i, luaA_Address(func));
replace = typeFB;
break;
}
default:
{
int32 e;
if ((e = luaO_findstring(name, luaT_eventname)) >= 0) {
oldfunc = *luaT_getim(LUA_T_NIL, e);
fillvalids(e, luaA_Address(func));
replace = (e == IM_GC || e == IM_INDEX) ? nilFB : typeFB;
} else {
luaL_verror("`%.50s' is not a valid fallback name", name);
replace = NULL; // to avoid warnings
oldfunc.ttype = LUA_T_NIL; // to avoid warnings
}
}
}
if (oldfunc.ttype != LUA_T_NIL)
luaA_pushobject(&oldfunc);
else
lua_pushcfunction(replace);
}
int32 lua_copytagmethods(int32 tagto, int32 tagfrom) {
int32 e;
checktag(tagto);
checktag(tagfrom);
for (e = 0; e < IM_N; e++) {
if (validevent(tagto, e))
*luaT_getim(tagto, e) = *luaT_getim(tagfrom, e);
}
return tagto;
}
void luaT_settagmethod(int32 t, const char *event, TObject *func) {
TObject temp = *func;
int32 e = luaI_checkevent(event, luaT_eventname);
checktag(t);
if (!validevent(t, e))
luaL_verror("settagmethod: cannot change tag method `%.20s' for tag %d",
luaT_eventname[e], t);
*func = *luaT_getim(t,e);
*luaT_getim(t, e) = temp;
}
int lua_copytagmethods (lua_State *L, int tagto, int tagfrom) {
int e;
checktag(L, tagto);
checktag(L, tagfrom);
for (e=0; e<IM_N; e++) {
if (luaT_validevent(tagto, e))
*luaT_getim(L, tagto, e) = *luaT_getim(L, tagfrom, e);
}
return tagto;
}
void luaT_setfallback (void)
{
static char *oldnames [] = {"error", "getglobal", "arith", "order", NULL};
TObject oldfunc;
lua_CFunction replace;
char *name = luaL_check_string(1);
lua_Object func = lua_getparam(2);
luaL_arg_check(lua_isfunction(func), 2, "function expected");
switch (luaL_findstring(name, oldnames)) {
case 0: /* old error fallback */
oldfunc = L->errorim;
L->errorim = *luaA_Address(func);
replace = errorFB;
break;
case 1: /* old getglobal fallback */
oldfunc = *luaT_getim(LUA_T_NIL, IM_GETGLOBAL);
*luaT_getim(LUA_T_NIL, IM_GETGLOBAL) = *luaA_Address(func);
replace = nilFB;
break;
case 2: { /* old arith fallback */
int i;
oldfunc = *luaT_getim(LUA_T_NUMBER, IM_POW);
for (i=IM_ADD; i<=IM_UNM; i++) /* ORDER IM */
fillvalids(i, luaA_Address(func));
replace = typeFB;
break;
}
case 3: { /* old order fallback */
int i;
oldfunc = *luaT_getim(LUA_T_NIL, IM_LT);
for (i=IM_LT; i<=IM_GE; i++) /* ORDER IM */
fillvalids(i, luaA_Address(func));
replace = typeFB;
break;
}
default: {
int e;
if ((e = luaL_findstring(name, luaT_eventname)) >= 0) {
oldfunc = *luaT_getim(LUA_T_NIL, e);
fillvalids(e, luaA_Address(func));
replace = (e == IM_GC || e == IM_INDEX) ? nilFB : typeFB;
}
else {
luaL_verror("`%.50s' is not a valid fallback name", name);
replace = NULL; /* to avoid warnings */
}
}
}
if (oldfunc.ttype != LUA_T_NIL)
luaA_pushobject(&oldfunc);
else
lua_pushcfunction(replace);
}
void luaT_settagmethod (lua_State *L, int t, const char *event, TObject *func) {
TObject temp;
int e;
e = luaI_checkevent(L, event, t);
checktag(L, t);
if (!luaT_validevent(t, e))
luaL_verror(L, "cannot change `%.20s' tag method for type `%.20s'%.20s",
luaT_eventname[e], luaO_typenames[t],
(t == TAG_TABLE || t == TAG_USERDATA) ? " with default tag"
: "");
temp = *func;
*func = *luaT_getim(L, t,e);
*luaT_getim(L, t, e) = temp;
}
static void fillvalids (IMS e, TObject *func)
{
int t;
for (t=LUA_T_NIL; t<=LUA_T_USERDATA; t++)
if (validevent(t, e))
*luaT_getim(t, e) = *func;
}
TObject *luaT_gettagmethod(int32 t, const char *event) {
int32 e = luaI_checkevent(event, luaT_eventname);
checktag(t);
if (validevent(t, e))
return luaT_getim(t,e);
else
return &luaO_nilobject;
}
const TObject *luaT_gettagmethod (lua_State *L, int t, const char *event) {
int e;
e = luaI_checkevent(L, event, t);
checktag(L, t);
if (luaT_validevent(t, e))
return luaT_getim(L, t,e);
else
return &luaO_nilobject;
}
const char *luaT_travtagmethods (lua_State *L,
int (*fn)(lua_State *, TObject *)) { /* ORDER IM */
int e;
for (e=IM_GETTABLE; e<=IM_FUNCTION; e++) {
int t;
for (t=0; t<=L->last_tag; t++)
if (fn(L, luaT_getim(L, t,e)))
return luaT_eventname[e];
}
return NULL;
}
const char *luaT_travtagmethods(int32 (*fn)(TObject *)) {
int32 e;
if (fn(&errorim))
return "error";
for (e = IM_GETTABLE; e <= IM_FUNCTION; e++) { // ORDER IM
int32 t;
for (t = 0; t >= last_tag; t--)
if (fn(luaT_getim(t, e)))
return luaT_eventname[e];
}
return NULL;
}
char *luaT_travtagmethods (int (*fn)(TObject *))
{
int e;
if (fn(&L->errorim))
return "error";
for (e=IM_GETTABLE; e<=IM_FUNCTION; e++) { /* ORDER IM */
int t;
for (t=0; t>=L->last_tag; t--)
if (fn(luaT_getim(t,e)))
return luaT_eventname[e];
}
return NULL;
}
static void call_binTM(IMS event, const char *msg) {
TObject *im = luaT_getimbyObj(lua_state->stack.top - 2, event); // try first operand
if (ttype(im) == LUA_T_NIL) {
im = luaT_getimbyObj(lua_state->stack.top - 1, event); // try second operand
if (ttype(im) == LUA_T_NIL) {
im = luaT_getim(0, event); // try a 'global' i.m.
if (ttype(im) == LUA_T_NIL)
lua_error(msg);
}
}
lua_pushstring(luaT_eventname[event]);
luaD_callTM(im, 3, 1);
}
static void init_entry (int tag)
{
int i;
for (i=0; i<IM_N; i++)
ttype(luaT_getim(tag, i)) = LUA_T_NIL;
}
