Communication by mutating shared variables is not a solution. On 21 Aug 2017 12:47 pm, "Naveen Chawla" <[email protected]> wrote:
> Currently you can set one or more variables outside the scope of the > generator function during iteration, which the generator function can read. > Is this so bad? > > On Mon, 21 Aug 2017 at 15:24 Marius Gundersen <[email protected]> wrote: > >> Generators today can both "send" a value and "receive" a value from their >> consumer, so they can act as an interactive iterable. See for example >> [fibonacci with reset](https://developer.mozilla.org/en/docs/Web/ >> JavaScript/Guide/Iterators_and_Generators#Advanced_generators) >> >> While generators are "producers" of values, the for-of statement acts as >> a "consumer" of these values. But unfortunately the for-of cannot send >> values back to the generator: >> >> ```js >> for(const value of fibonacci()){ >> console.log(value); >> //no way to reset it :( >> } >> ``` >> >> I propose a for-of-with statement, like so: >> >> ```js >> let feedback = false; >> for(const value of fibonacci() with feedback){ >> console.log(value) >> feedback = value == 8; >> } >> ``` >> >> Note that the variable has to be defined before the for-of-with >> statement, but the initial value will not be seen inside the generator >> until [function.sent](https://github.com/allenwb/ESideas/ >> blob/master/Generator%20metaproperty.md) is implemented. >> >> The babel output of the for-of-with statement would be the following: >> >> ```js >> var reset = false; >> var _iteratorNormalCompletion = true; >> var _didIteratorError = false; >> var _iteratorError = undefined; >> >> try { >> for (var _iterator = fibonacci()[Symbol.iterator](), _step; >> !(_iteratorNormalCompletion = (_step = _iterator.next(reset)).done); >> _iteratorNormalCompletion = true) { >> var value = _step.value; >> >> console.log(value); >> reset = value == 8; >> } >> } catch (err) { >> _didIteratorError = true; >> _iteratorError = err; >> } finally { >> try { >> if (!_iteratorNormalCompletion && _iterator.return) { >> _iterator.return(); >> } >> } finally { >> if (_didIteratorError) { >> throw _iteratorError; >> } >> } >> } >> ``` >> >> Marius Gundersen >> _______________________________________________ >> es-discuss mailing list >> [email protected] >> https://mail.mozilla.org/listinfo/es-discuss >> > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > >
_______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
