static void retstat (LexState *ls) {
/* stat -> RETURN explist */
FuncState *fs = ls->fs;
expdesc e;
int first, nret; /* registers with returned values */
luaX_next(ls); /* skip RETURN */
if (block_follow(ls->t.token) || ls->t.token == ';')
first = nret = 0; /* return no values */
else {
nret = explist1(ls, &e); /* optional return values */
if (hasmultret(e.k)) {
luaK_setmultret(fs, &e);
if (e.k == VCALL && nret == 1) { /* tail call? */
SET_OPCODE(getcode(fs,&e), OP_TAILCALL);
lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar);
}
first = fs->nactvar;
nret = LUA_MULTRET; /* return all values */
}
else {
if (nret == 1) /* only one single value? */
first = luaK_exp2anyreg(fs, &e);
else {
luaK_exp2nextreg(fs, &e); /* values must go to the `stack' */
first = fs->nactvar; /* return all `active' values */
lua_assert(nret == fs->freereg - first);
}
}
}
luaK_ret(fs, first, nret);
}
static void funcargs(LexState* ls, expdesc* f)
{
FuncState* fs = ls->fs;
expdesc args;
int base, nparams;
int line = ls->linenumber;
switch (ls->t.token)
{
case '(': /* funcargs -> `(' [ explist1 ] `)' */
{
if (line != ls->lastline)
luaX_syntaxerror(ls, "ambiguous syntax (function call x new statement)");
luaX_next(ls);
if (ls->t.token == ')') /* arg list is empty? */
args.k = VVOID;
else
{
explist1(ls, &args);
luaK_setmultret(fs, &args);
}
check_match(ls, ')', '(', line);
break;
}
case '{': /* funcargs -> constructor */
{
constructor(ls, &args);
break;
}
case TK_STRING: /* funcargs -> STRING */
{
codestring(ls, &args, ls->t.seminfo.ts);
luaX_next(ls); /* must use `seminfo' before `next' */
break;
}
default:
{
luaX_syntaxerror(ls, "function arguments expected");
return;
}
}
lua_assert(f->k == VNONRELOC);
base = f->u.s.info; /* base register for call */
if (hasmultret(args.k))
nparams = LUA_MULTRET; /* open call */
else
{
if (args.k != VVOID)
luaK_exp2nextreg(fs, &args); /* close last argument */
nparams = fs->freereg - (base + 1);
}
init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams + 1, 2));
luaK_fixline(fs, line);
fs->freereg = base + 1; /* call remove function and arguments and leaves
(unless changed) one result */
}
static void lastlistfield (FuncState *fs, struct ConsControl *cc) {
if (cc->tostore == 0) return;
if (hasmultret(cc->v.k)) {
luaK_setmultret(fs, &cc->v);
luaK_setlist(fs, cc->t->u.s.info, cc->na, LUA_MULTRET);
cc->na--; /* do not count last expression (unknown number of elements) */
}
else {
if (cc->v.k != VVOID)
luaK_exp2nextreg(fs, &cc->v);
luaK_setlist(fs, cc->t->u.s.info, cc->na, cc->tostore);
}
}
static void retstat (LexState *ls) {
/* stat -> RETURN explist */
FuncState *fs = ls->fs;
BlockCnt *bl = fs->bl;
expdesc e;
int first, nret; /* registers with returned values */
int ret_in_try = 0;
luaX_next(ls); /* skip RETURN */
if (block_follow(ls->t.token) || ls->t.token == ';')
first = nret = 0; /* return no values */
else {
nret = explist1(ls, &e); /* optional return values */
if (hasmultret(e.k)) {
luaK_setmultret(fs, &e);
if (e.k == VCALL && nret == 1) { /* tail call? */
SET_OPCODE(getcode(fs,&e), OP_TAILCALL);
lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar);
}
first = fs->nactvar;
nret = LUA_MULTRET; /* return all values */
}
else {
if (nret == 1) /* only one single value? */
first = luaK_exp2anyreg(fs, &e);
else {
luaK_exp2nextreg(fs, &e); /* values must go to the `stack' */
first = fs->nactvar; /* return all `active' values */
lua_assert(nret == fs->freereg - first);
}
}
}
/* before return, we should exit all try-catch blocks */
while (bl) {
if (bl->isbreakable == 2) {
if (ret_in_try)
luaK_codeABC(fs, OP_EXITTRY, 0, 0, 0);
else {
ret_in_try = 1;
luaK_codeABC(fs, OP_EXITTRY, first, nret+1, 1); /* here we will save all return values */
}
} else if (bl->isbreakable == 3)
luaX_syntaxerror(ls, "can't return in _finally_ clause");
bl = bl->previous;
}
luaK_codeABC(fs, OP_RETURN, first, nret+1, ret_in_try);
}
