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correct semantics for comparison metamethods (they are only valid

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when both operands have the same metamethod).
This commit is contained in:
Roberto Ierusalimschy 2003-01-27 13:12:52 -02:00
parent 41ed3c4771
commit e79bf02f33
1 changed files with 42 additions and 15 deletions
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57
lvm.c
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@ -1,5 +1,5 @@
/*
** $Id: lvm.c,v 1.272 2002/12/06 17:09:00 roberto Exp roberto $
** $Id: lvm.c,v 1.273 2002/12/11 12:34:22 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@ -204,6 +204,33 @@ static int call_binTM (lua_State *L, const TObject *p1, const TObject *p2,
}
static const TObject *get_compTM (lua_State *L, Table *mt1, Table *mt2,
TMS event) {
const TObject *tm1 = fasttm(L, mt1, event);
const TObject *tm2;
if (tm1 == NULL) return NULL; /* no metamethod */
if (mt1 == mt2) return tm1; /* same metatables => same metamethods */
tm2 = fasttm(L, mt2, event);
if (tm2 == NULL) return NULL; /* no metamethod */
if (luaO_rawequalObj(tm1, tm2)) /* same metamethods? */
return tm1;
return NULL;
}
static int call_orderTM (lua_State *L, const TObject *p1, const TObject *p2,
TMS event) {
const TObject *tm1 = luaT_gettmbyobj(L, p1, event);
const TObject *tm2;
if (ttisnil(tm1)) return -1; /* no metamethod? */
tm2 = luaT_gettmbyobj(L, p2, event);
if (!luaO_rawequalObj(tm1, tm2)) /* different metamethods? */
return -1;
callTMres(L, tm1, p1, p2);
return !l_isfalse(L->top);
}
static int luaV_strcmp (const TString *ls, const TString *rs) {
const char *l = getstr(ls);
size_t ll = ls->tsv.len;
@ -227,29 +254,31 @@ static int luaV_strcmp (const TString *ls, const TString *rs) {
int luaV_lessthan (lua_State *L, const TObject *l, const TObject *r) {
int res;
if (ttype(l) != ttype(r))
return luaG_ordererror(L, l, r);
else if (ttisnumber(l))
return nvalue(l) < nvalue(r);
else if (ttisstring(l))
return luaV_strcmp(tsvalue(l), tsvalue(r)) < 0;
else if (call_binTM(L, l, r, L->top, TM_LT))
return !l_isfalse(L->top);
else if ((res = call_orderTM(L, l, r, TM_LT)) != -1)
return res;
return luaG_ordererror(L, l, r);
}
static int luaV_lessequal (lua_State *L, const TObject *l, const TObject *r) {
int res;
if (ttype(l) != ttype(r))
return luaG_ordererror(L, l, r);
else if (ttisnumber(l))
return nvalue(l) <= nvalue(r);
else if (ttisstring(l))
return luaV_strcmp(tsvalue(l), tsvalue(r)) <= 0;
else if (call_binTM(L, l, r, L->top, TM_LE)) /* first try `le' */
return !l_isfalse(L->top);
else if (call_binTM(L, r, l, L->top, TM_LT)) /* else try `lt' */
return l_isfalse(L->top);
else if ((res = call_orderTM(L, l, r, TM_LE)) != -1) /* first try `le' */
return res;
else if ((res = call_orderTM(L, r, l, TM_LT)) != -1) /* else try `lt' */
return !res;
return luaG_ordererror(L, l, r);
}
@ -264,20 +293,18 @@ int luaV_equalval (lua_State *L, const TObject *t1, const TObject *t2) {
case LUA_TLIGHTUSERDATA: return pvalue(t1) == pvalue(t2);
case LUA_TUSERDATA: {
if (uvalue(t1) == uvalue(t2)) return 1;
else if ((tm = fasttm(L, uvalue(t1)->uv.metatable, TM_EQ)) == NULL &&
(tm = fasttm(L, uvalue(t2)->uv.metatable, TM_EQ)) == NULL)
return 0; /* no TM */
else break; /* will try TM */
tm = get_compTM(L, uvalue(t1)->uv.metatable, uvalue(t2)->uv.metatable,
TM_EQ);
break; /* will try TM */
}
case LUA_TTABLE: {
if (hvalue(t1) == hvalue(t2)) return 1;
else if ((tm = fasttm(L, hvalue(t1)->metatable, TM_EQ)) == NULL &&
(tm = fasttm(L, hvalue(t2)->metatable, TM_EQ)) == NULL)
return 0; /* no TM */
else break; /* will try TM */
tm = get_compTM(L, hvalue(t1)->metatable, hvalue(t2)->metatable, TM_EQ);
break; /* will try TM */
}
default: return gcvalue(t1) == gcvalue(t2);
}
if (tm == NULL) return 0; /* no TM? */
callTMres(L, tm, t1, t2); /* call TM */
return !l_isfalse(L->top);
}