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new semantics for `generic for' (with state)

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Roberto Ierusalimschy
2002-04-09 16:47:44 -03:00
parent d2e05589d7
commit 7b65328c8e
5 changed files with 35 additions and 31 deletions
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24
lparser.c
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@@ -1,5 +1,5 @@
/*
** $Id: lparser.c,v 1.173 2002/03/25 17:47:14 roberto Exp roberto $
** $Id: lparser.c,v 1.174 2002/04/02 20:34:15 roberto Exp roberto $
** Lua Parser
** See Copyright Notice in lua.h
*/
@@ -331,6 +331,7 @@ static void enterblock (FuncState *fs, BlockCnt *bl, int isbreakable) {
bl->upval = 0;
bl->previous = fs->bl;
fs->bl = bl;
lua_assert(fs->freereg == fs->nactloc);
}
@@ -1028,24 +1029,25 @@ static void fornum (LexState *ls, TString *varname, int line) {
static void forlist (LexState *ls, TString *indexname) {
/* forlist -> NAME {,NAME} IN exp1 DO body */
/* forlist -> NAME {,NAME} IN explist1 DO body */
FuncState *fs = ls->fs;
expdesc e;
int nvars = 0;
int prep;
int base = fs->freereg;
new_localvarstr(ls, "(for generator)", 0);
new_localvar(ls, indexname, ++nvars);
new_localvarstr(ls, "(for generator)", nvars++);
new_localvarstr(ls, "(for state)", nvars++);
new_localvar(ls, indexname, nvars++);
while (optional(ls, ',')) {
new_localvar(ls, str_checkname(ls), ++nvars);
new_localvar(ls, str_checkname(ls), nvars++);
next(ls);
}
check(ls, TK_IN);
exp1(ls); /* table */
luaK_checkstack(fs, 2); /* at least two slots, to traverse tables */
luaK_reserveregs(fs, nvars); /* registers for vars */
luaK_codeABC(fs, OP_LOADNIL, base+1, base+nvars, 0);
adjustlocalvars(ls, nvars+1); /* scope for control variables */
luaK_codeABC(fs, OP_TFORLOOP, base, 0, nvars);
adjust_assign(ls, 3, explist1(ls, &e), &e);
luaK_reserveregs(fs, nvars - 3); /* registers for other variables */
luaK_codeABC(fs, OP_TFORPREP, base, 0, 0);
luaK_codeABC(fs, OP_TFORLOOP, base, 0, nvars - 3);
adjustlocalvars(ls, nvars); /* scope for all variables */
prep = luaK_jump(fs);
check(ls, TK_DO);
block(ls);