From 0bda88e6cd960d3b1ad1d46826bfdef179098d2a Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Fri, 14 May 2004 16:25:09 -0300
Subject: small steps towards yields in iterators and tag methods
---
ldo.c | 30 ++++++++++++++++++------------
1 file changed, 18 insertions(+), 12 deletions(-)
(limited to 'ldo.c')
diff --git a/ldo.c b/ldo.c
index f2682670..fc1caa7f 100644
--- a/ldo.c
+++ b/ldo.c
@@ -1,5 +1,5 @@
/*
-** $Id: ldo.c,v 2.3 2004/04/30 20:13:38 roberto Exp roberto $
+** $Id: ldo.c,v 2.4 2004/05/10 17:50:51 roberto Exp roberto $
** Stack and Call structure of Lua
** See Copyright Notice in lua.h
*/
@@ -219,7 +219,7 @@ static StkId tryfuncTM (lua_State *L, StkId func) {
}
-StkId luaD_precall (lua_State *L, StkId func) {
+int luaD_precall (lua_State *L, StkId func, int nresults) {
LClosure *cl;
ptrdiff_t funcr = savestack(L, func);
if (!ttisfunction(func)) /* `func' is not a function? */
@@ -239,10 +239,11 @@ StkId luaD_precall (lua_State *L, StkId func) {
ci->top = L->base + p->maxstacksize;
ci->u.l.savedpc = p->code; /* starting point */
ci->u.l.tailcalls = 0;
+ ci->nresults = nresults;
for (st = L->top; st < ci->top; st++)
setnilvalue(st);
L->top = ci->top;
- return NULL;
+ return PCRLUA;
}
else { /* if is a C function, call it */
CallInfo *ci;
@@ -256,7 +257,14 @@ StkId luaD_precall (lua_State *L, StkId func) {
lua_unlock(L);
n = (*curr_func(L)->c.f)(L); /* do the actual call */
lua_lock(L);
- return L->top - n;
+ if (n >= 0) { /* no yielding? */
+ luaD_poscall(L, nresults, L->top - n);
+ return PCRC;
+ }
+ else {
+ ci->nresults = nresults;
+ return PCRYIELD;
+ }
}
}
@@ -297,17 +305,16 @@ void luaD_poscall (lua_State *L, int wanted, StkId firstResult) {
** function position.
*/
void luaD_call (lua_State *L, StkId func, int nResults) {
- StkId firstResult;
if (++L->nCcalls >= LUA_MAXCCALLS) {
if (L->nCcalls == LUA_MAXCCALLS)
luaG_runerror(L, "C stack overflow");
else if (L->nCcalls >= (LUA_MAXCCALLS + (LUA_MAXCCALLS>>3)))
luaD_throw(L, LUA_ERRERR); /* error while handing stack error */
}
- firstResult = luaD_precall(L, func);
- if (firstResult == NULL) /* is a Lua function? */
- firstResult = luaV_execute(L, 1); /* call it */
- luaD_poscall(L, nResults, firstResult);
+ if (luaD_precall(L, func, nResults) == PCRLUA) { /* is a Lua function? */
+ StkId firstResult = luaV_execute(L, 1); /* call it */
+ luaD_poscall(L, nResults, firstResult);
+ }
L->nCcalls--;
luaC_checkGC(L);
}
@@ -319,15 +326,14 @@ static void resume (lua_State *L, void *ud) {
CallInfo *ci = L->ci;
if (!L->isSuspended) {
lua_assert(ci == L->base_ci && nargs < L->top - L->base);
- luaD_precall(L, L->top - (nargs + 1)); /* start coroutine */
+ luaD_precall(L, L->top - (nargs + 1), LUA_MULTRET); /* start coroutine */
}
else { /* resuming from previous yield */
if (!f_isLua(ci)) { /* `common' yield? */
/* finish interrupted execution of `OP_CALL' */
- int nresults;
+ int nresults = ci->nresults;
lua_assert(GET_OPCODE(*((ci-1)->u.l.savedpc - 1)) == OP_CALL ||
GET_OPCODE(*((ci-1)->u.l.savedpc - 1)) == OP_TAILCALL);
- nresults = GETARG_C(*((ci-1)->u.l.savedpc - 1)) - 1;
luaD_poscall(L, nresults, L->top - nargs); /* complete it */
if (nresults >= 0) L->top = L->ci->top;
} /* else yielded inside a hook: just continue its execution */
--
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