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first version of empty entries in tables

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(so that, in the future, tables can contain regular nil entries)
This commit is contained in:
Roberto Ierusalimschy
2018-02-23 10:16:18 -03:00
parent 477ca2fe8c
commit 9243c414d9
11 changed files with 146 additions and 99 deletions
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21
lvm.c
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@@ -1,5 +1,5 @@
/*
** $Id: lvm.c,v 2.345 2018/02/21 15:49:32 roberto Exp roberto $
** $Id: lvm.c,v 2.346 2018/02/21 19:43:44 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@@ -168,7 +168,7 @@ static int forlimit (const TValue *obj, lua_Integer *p, lua_Integer step,
/*
** Finish the table access 'val = t[key]'.
** if 'slot' is NULL, 't' is not a table; otherwise, 'slot' points to
** t[k] entry (which must be nil).
** t[k] entry (which must be empty).
*/
void luaV_finishget (lua_State *L, const TValue *t, TValue *key, StkId val,
const TValue *slot) {
@@ -178,12 +178,12 @@ void luaV_finishget (lua_State *L, const TValue *t, TValue *key, StkId val,
if (slot == NULL) { /* 't' is not a table? */
lua_assert(!ttistable(t));
tm = luaT_gettmbyobj(L, t, TM_INDEX);
if (ttisnil(tm))
if (notm(tm))
luaG_typeerror(L, t, "index"); /* no metamethod */
/* else will try the metamethod */
}
else { /* 't' is a table */
lua_assert(ttisnil(slot));
lua_assert(isempty(slot));
tm = fasttm(L, hvalue(t)->metatable, TM_INDEX); /* table's metamethod */
if (tm == NULL) { /* no metamethod? */
setnilvalue(s2v(val)); /* result is nil */
@@ -209,8 +209,8 @@ void luaV_finishget (lua_State *L, const TValue *t, TValue *key, StkId val,
/*
** Finish a table assignment 't[key] = val'.
** If 'slot' is NULL, 't' is not a table. Otherwise, 'slot' points
** to the entry 't[key]', or to 'luaO_nilobject' if there is no such
** entry. (The value at 'slot' must be nil, otherwise 'luaV_fastget'
** to the entry 't[key]', or to 'luaH_emptyobject' if there is no such
** entry. (The value at 'slot' must be empty, otherwise 'luaV_fastget'
** would have done the job.)
*/
void luaV_finishset (lua_State *L, const TValue *t, TValue *key,
@@ -220,10 +220,10 @@ void luaV_finishset (lua_State *L, const TValue *t, TValue *key,
const TValue *tm; /* '__newindex' metamethod */
if (slot != NULL) { /* is 't' a table? */
Table *h = hvalue(t); /* save 't' table */
lua_assert(ttisnil(slot)); /* old value must be nil */
lua_assert(isempty(slot)); /* slot must be empty */
tm = fasttm(L, h->metatable, TM_NEWINDEX); /* get metamethod */
if (tm == NULL) { /* no metamethod? */
if (slot == luaO_nilobject) /* no previous entry? */
if (slot == luaH_emptyobject) /* no previous entry? */
slot = luaH_newkey(L, h, key); /* create one */
/* no metamethod and (now) there is an entry with given key */
setobj2t(L, cast(TValue *, slot), val); /* set its new value */
@@ -234,7 +234,8 @@ void luaV_finishset (lua_State *L, const TValue *t, TValue *key,
/* else will try the metamethod */
}
else { /* not a table; check metamethod */
if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_NEWINDEX)))
tm = luaT_gettmbyobj(L, t, TM_NEWINDEX);
if (notm(tm))
luaG_typeerror(L, t, "index");
}
/* try the metamethod */
@@ -586,7 +587,7 @@ void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) {
}
default: { /* try metamethod */
tm = luaT_gettmbyobj(L, rb, TM_LEN);
if (ttisnil(tm)) /* no metamethod? */
if (notm(tm)) /* no metamethod? */
luaG_typeerror(L, rb, "get length of");
break;
}