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tables and strings respect __len metamethod

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This commit is contained in:
Roberto Ierusalimschy 2007-09-10 14:59:32 -03:00
parent 8acaa2ce07
commit fe0838cd1c
3 changed files with 34 additions and 23 deletions
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6
ltm.c
View File

@ -1,5 +1,5 @@
/*
** $Id: ltm.c,v 2.7 2005/12/22 16:19:56 roberto Exp roberto $
** $Id: ltm.c,v 2.8 2006/01/10 12:50:00 roberto Exp roberto $
** Tag methods
** See Copyright Notice in lua.h
*/
@ -30,9 +30,9 @@ const char *const luaT_typenames[] = {
void luaT_init (lua_State *L) {
static const char *const luaT_eventname[] = { /* ORDER TM */
"__index", "__newindex",
"__gc", "__mode", "__eq",
"__gc", "__mode", "__len", "__eq",
"__add", "__sub", "__mul", "__div", "__mod",
"__pow", "__unm", "__len", "__lt", "__le",
"__pow", "__unm", "__lt", "__le",
"__concat", "__call"
};
int i;

4
ltm.h
View File

@ -1,5 +1,5 @@
/*
** $Id: ltm.h,v 2.5 2005/05/20 15:53:42 roberto Exp roberto $
** $Id: ltm.h,v 2.6 2005/06/06 13:30:25 roberto Exp roberto $
** Tag methods
** See Copyright Notice in lua.h
*/
@ -20,6 +20,7 @@ typedef enum {
TM_NEWINDEX,
TM_GC,
TM_MODE,
TM_LEN,
TM_EQ, /* last tag method with `fast' access */
TM_ADD,
TM_SUB,
@ -28,7 +29,6 @@ typedef enum {
TM_MOD,
TM_POW,
TM_UNM,
TM_LEN,
TM_LT,
TM_LE,
TM_CONCAT,

47
lvm.c
View File

@ -1,5 +1,5 @@
/*
** $Id: lvm.c,v 2.71 2007/03/26 15:56:23 roberto Exp roberto $
** $Id: lvm.c,v 2.72 2007/06/19 19:48:15 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@ -310,6 +310,33 @@ void luaV_concat (lua_State *L, int total, int last) {
}
static void objlen (lua_State *L, StkId ra, const TValue *rb) {
const TValue *tm;
switch (ttype(rb)) {
case LUA_TTABLE: {
Table *h = hvalue(rb);
tm = fasttm(L, h->metatable, TM_LEN);
if (tm) break; /* metamethod? break switch to call it */
setnvalue(ra, cast_num(luaH_getn(h))); /* else primitive len */
return;
}
case LUA_TSTRING: {
tm = fasttm(L, G(L)->mt[LUA_TSTRING], TM_LEN);
if (tm) break; /* metamethod? break switch to call it */
setnvalue(ra, cast_num(tsvalue(rb)->len));
return;
}
default: { /* try metamethod */
tm = luaT_gettmbyobj(L, rb, TM_LEN);
if (ttisnil(tm)) /* no metamethod? */
luaG_typeerror(L, rb, "get length of");
break;
}
}
callTMres(L, ra, tm, rb, luaO_nilobject);
}
static void Arith (lua_State *L, StkId ra, const TValue *rb,
const TValue *rc, TMS op) {
TValue tempb, tempc;
@ -509,23 +536,7 @@ void luaV_execute (lua_State *L, int nexeccalls) {
continue;
}
case OP_LEN: {
const TValue *rb = RB(i);
switch (ttype(rb)) {
case LUA_TTABLE: {
setnvalue(ra, cast_num(luaH_getn(hvalue(rb))));
break;
}
case LUA_TSTRING: {
setnvalue(ra, cast_num(tsvalue(rb)->len));
break;
}
default: { /* try metamethod */
Protect(
if (!call_binTM(L, rb, rb, ra, TM_LEN))
luaG_typeerror(L, rb, "get length of");
)
}
}
Protect(objlen(L, ra, RB(i)));
continue;
}
case OP_CONCAT: {