Slight suggestions about luaB_print() ?
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- Subject: Slight suggestions about luaB_print() ?
- From: Majic <majic.one@...>
- Date: 2010年1月17日 00:46:44 -0800
static int luaB_print (lua_State *L) {
int n = lua_gettop(L); /* number of arguments */
int i;
lua_getglobal(L, "tostring");
for (i=1; i<=n; i++) {
const char *s;
lua_pushvalue(L, -1); /* function to be called */
lua_pushvalue(L, i); /* value to print */
lua_call(L, 1, 1);
s = lua_tostring(L, -1); /* get result */
if (s == NULL)
return luaL_error(L, LUA_QL("tostring") " must return a string to "
LUA_QL("print"));
if (i>1) fputs("\t", stdout);
fputs(s, stdout);
lua_pop(L, 1); /* pop result */
}
fputs("\n", stdout);
return 0;
}
I was looking over Lua's print() to understand what exactly it doctors
in case of more than one argument and I noticed that instead of
lua_pop()'ing the converted string, you could reference the
lua_getglobal(L, "tostring") with just lua_pushvalue(L, nargs + 1);
I'm just not sure if this is a good idea if the stack can't grow on
forever without penalty? I just thought it might (possibly?) be more
efficient to let those converted strings be popped anyway when we
return from the function. You can also declare int n as const but I
don't know how much good it would do... I see the fputs() was replaced
with a luai_writestring() in 5.2, so that is a good thing :)
Anyway, it just struck me as a bit odd so I hope the suggestion won't
be taken poorly.
Regards