Current environment

[Nodir Temirhodzhaev <tnodir@...>]

Hello!

I suggest to use by default environment of "current" thread or of function, if it specially setted by setfenv.

lua5.0: ldo.c: f_parser {
...
  cl = luaF_newLclosure(L, 0, gt(L));
  cl->l.g.tt = LUA_TNIL; //+
...
}

lua5.0: lvm.c: luaV_execute {
...
      case OP_GETGLOBAL: {
        const TObject *g = ttistable(&cl->g) ? &cl->g : gt(L); //+
        TObject *rb = KBx(i);
        const TObject *v;
        lua_assert(ttisstring(rb) && ttistable(g)); //&cl->g
        v = luaH_getstr(hvalue(g), tsvalue(rb)); //&cl->g
        if (!ttisnil(v)) { setobj2s(ra, v); }
        else
          setobj2s(XRA(i), luaV_index(L, g, rb, 0)); //&cl->g
        break;
      }
...
      case OP_SETGLOBAL: {
        const TObject *g = ttistable(&cl->g) ? &cl->g : gt(L); //+
        lua_assert(ttisstring(KBx(i)) && ttistable(g)); //&cl->g
        luaV_settable(L, g, KBx(i), ra); //&cl->g
        break;
      }
...
}


=====
local function inc() print(out) end

--setfenv(inc, setmetatable({out = "fenv"}, {__index = _G}))

local function th(arg)
	setfenv(0, setmetatable({out = arg}, {__index = _G}))
	coroutine.yield()
	inc()
end

local a = coroutine.create(th)
local b = coroutine.create(th)
coroutine.resume(a, 'a')
coroutine.resume(b, 'b')
coroutine.resume(a)
coroutine.resume(b)
=====
Prints:
a
b

If uncomment 3 line:
fenv
fenv