> -----Original Message-----
> From: Anthony Ferrara [mailto:[email protected]]
> Sent: 13 August 2012 03:49
> To: Brian Moon
> Cc: Nikita Popov; PHP internals
> Subject: Re: [PHP-DEV] [RFC] Generators
>
> Brian,
>
> On Sun, Aug 12, 2012 at 4:08 PM, Brian Moon
> <[email protected]> wrote:
>
> > Hi Nikita,
> >
> > I admit, I have ignored these threads as there was no RFC.
> So, some of
> > this may have been covered.
> >
>
> There was an RFC in those posts... It was just being iterated over.
>
>
> > Do you have a good example usage other than a file? I don't find
> > fopen/fgets/fclose all that complicated. What are the other
> valid use
> > cases for such a thing?
> >
>
> Here's a quick set of examples:
>
http://blog.ircmaxell.com/2012/07/what-generators-can-do-for-you.html
>
>
> > Also, not allowing rewinding is unintuitive for something
> that is an
> > iterator in PHP. If I can foreach() it and I can call
> next() on it, I
> > expect to be able to reset() it as well. IMO, you would
> need to issue
> > a FATAL PHP error if that simply is not allowed. Or you
> have to have a
> > second syntax for what to do in that case. At that point, you are
> > implementing Iterator.
> >
>
> I partially agree. rewinding the generator might be possible,
> but it's hard to tell in those cases. It's hard to tell if
> resetting it is even possible from the code level. So I'm
> pretty much OK with living with that restriction for the time
being...
>
>
> > While I am glad that PHP has borrowed syntax from many languages,
I
> > find the yield keyword to be very WTF when I first saw it.
> It is also
> > poorly explained in your RFC. You use terms like "sending and
> > receiving". That does not say "returns from function
> execution" to me.
> > I had to basically figure it out from the code examples.
> >
>
> It's absolutely something that takes getting used to. But
> it's also quite intuitive once you think about it. You're not
> "returning" back to the parent scope (exiting your scope),
> you're "yielding" a value to the parent scope, expecting to
> continue on later (think of it as a stop light where you let
> the other code run for a while until you go to the next one).
>
>
> > Lastly, because you cite needing this for sending data to
> PHPUnit, I
> > think this is a user land problem and not a core problem.
> In about 5
> > minutes I implemented a reusable Generator object that does
> exactly what you need.
> > http://pastebin.com/V336rEpR At least, it does what your
> examples show
> > you need. Again, file IO is very easy and perhaps that example
does
> > not explain your true need very well.
> >
>
> Well, there's one thing that should be made clear. There's
> nothing (and I mean that) that generators provide that you
> can't do already. You can build iterators that do exactly the
> same thing.
Not true. Iterator::current() cannot return references, but generators
can yield them.
Eg
function &map(array &$row, array $order)
{
foreach($order as $index)
yield $row[$index];
}
foreach(map($row, [1,3,5,7,9]) as &$ref)
....
>
> Anthony
>
Jared
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