domenic at domenicdenicola.com (2013-11-02T19:02:40.969Z)
On Sat, Oct 26, 2013 at 1:01 PM, Lucio Tato <luciotato at gmail.com> wrote:
> It's really needed to make js syntax more complex in order to implement
> generators?
> It's function* really needed?
>
Yes, because `yield` is only reserved in strict mode code, which means this
is valid today:
```js
function g() { yield = 1; return yield; }
```
Since the starred generator function is a new syntactic form, there is no
existing code that it can possibly break by making yield a keyword.
> can you just expose "Generator" as a core function?
> can "yield" be a function-call-like-construct instead of a new language
> construction?
>
No, because there may already be code that defines a function called
`yield`, which would be broken if suddenly yield was a special
language-owned function. Consider this:
```js
// your code defines this...
function yield() { return Number.MAX_VALUE; }
// you then include my library, which exposes this fibonacci():
```
> ```js
> function fibonacci() {
> let [prev, curr] = [0, 1];
> for (;;) {
> [prev, curr] = [curr, prev + curr];
> yield(curr);
> }}
> ```
What does yield() do? It returns Number.MAX_VALUE every time.
On Sat, Oct 26, 2013 at 1:01 PM, Lucio Tato <luciotato at gmail.com> wrote: > It's really needed to make js syntax more complex in order to implement > generators? > It's function* really needed? > Yes, because `yield` is only reserved in strict mode code, which means this is valid today: function g() { yield = 1; return yield; } Since the starred generator function is a new syntactic form, there is no existing code that it can possibly break by making yield a keyword. > can you just expose "Generator" as a core function? > can "yield" be a function-call-like-construct instead of a new language > construction? > No, because there may already be code that defines a function called `yield`, which would be broken if suddenly yield was a special language-owned function. Consider this: // your code defines this... function yield() { return Number.MAX_VALUE; } // you then include my library, which exposes this fibonacci(): function fibonacci() { > let [prev, curr] = [0, 1]; > for (;;) { > [prev, curr] = [curr, prev + curr]; > yield(curr); > }} > > What does yield() do? It returns Number.MAX_VALUE every time. Rick -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.mozilla.org/pipermail/es-discuss/attachments/20131026/fbf6ec7b/attachment.html>