nik/lush
1
1
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

simpler implementation for `for' loops

Browse Source
This commit is contained in:
Roberto Ierusalimschy
2002-02-05 20:39:12 -02:00
parent addbe8c8b0
commit 38b0e6128d
7 changed files with 57 additions and 95 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
lparser.c
View File

@@ -955,17 +955,17 @@ static void exp1 (LexState *ls) {
}
static void forbody (LexState *ls, int nvar, OpCode prepfor, OpCode loopfor) {
static void forbody (LexState *ls, int nvar, OpCode loopfor) {
/* forbody -> DO block END */
FuncState *fs = ls->fs;
int basereg = fs->freereg - nvar;
int prep = luaK_codeAsBc(fs, prepfor, basereg, NO_JUMP);
int prep = luaK_jump(fs);
int blockinit = luaK_getlabel(fs);
check(ls, TK_DO);
adjustlocalvars(ls, nvar); /* scope for control variables */
block(ls);
luaK_patchlist(fs, prep, luaK_getlabel(fs));
luaK_patchlist(fs, luaK_codeAsBc(fs, loopfor, basereg, NO_JUMP), blockinit);
luaK_fixfor(fs, prep, luaK_getlabel(fs));
removelocalvars(ls, nvar, 1);
}
@@ -986,13 +986,15 @@ static void fornum (LexState *ls, TString *varname) {
new_localvar(ls, varname, 0);
new_localvarstr(ls, "(limit)", 1);
new_localvarstr(ls, "(step)", 2);
forbody(ls, 3, OP_FORPREP, OP_FORLOOP);
luaK_codeABC(fs, OP_SUB, fs->freereg - 3, fs->freereg - 3, fs->freereg - 1);
forbody(ls, 3, OP_FORLOOP);
}
static void forlist (LexState *ls, TString *indexname) {
/* forlist -> NAME,NAME IN exp1 forbody */
TString *valname;
FuncState *fs = ls->fs;
check(ls, ',');
valname = str_checkname(ls);
next(ls); /* skip var name */
@@ -1002,8 +1004,9 @@ static void forlist (LexState *ls, TString *indexname) {
new_localvarstr(ls, "(index)", 1);
new_localvar(ls, indexname, 2);
new_localvar(ls, valname, 3);
luaK_reserveregs(ls->fs, 3); /* registers for control, index and val */
forbody(ls, 4, OP_TFORPREP, OP_TFORLOOP);
luaK_reserveregs(fs, 3); /* registers for control, index and val */
luaK_codeABc(fs, OP_LOADK, fs->freereg - 3, luaK_numberK(fs, -1));
forbody(ls, 4, OP_TFORLOOP);
}