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Date: Fri, 17 Mar 2017 23:10:30 -0300
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To: Sara Golemon <pollita@php.net>
Cc: Niklas Keller <me@kelunik.com>, PHP Internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=94eb2c1920ac9b98a9054af7cd99
Subject: Re: [PHP-DEV] Let range() return a generator?
From: david.proweb@gmail.com (David Rodrigues)

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Yeah, sorry, it was a bad example -- I just noted after I submit. hehe

About "new Generator($arg)" I mean a method to flag the first argument on
function, that should identify that it should work differently or default
method (without allocate memory).
I guess that it is not implemented on PHP core, because until now have no
sense, but imagine something like that (I will write in PHP, but read it
like a C++):

PHP: new Generator(range(1, 1000))

C++ (range function):

if (getParentConstructor() === Generator::class) {
   // Yield each one.
} else {
   // Prepare on memory and return like an array.
}

In this case, when you call range() inside a Generator() constructor, then
the range() (in C++) will acts differently, like a xrange().




2017-03-17 22:57 GMT-03:00 Sara Golemon <pollita@php.net>:

> On Fri, Mar 17, 2017 at 8:40 PM, David Rodrigues <david.proweb@gmail.com>
> wrote:
> > There are some way to PHP be flagged before run some function, and
> > understand that you wants to return a Generator instead of array?
> > For instance: new Generator(range(1, 1000)) makes range() work like a
> > generator instead of return an array - it's an alternative to avoid new
> > keywords.
> > Or, maybe, some side implementation like Generator::range(1, 1000),
> > Generator::array_values($array), etc. (Currently, for instance, we can
> > simulate the range() Generator, but not array_values())
> >
> Why would array_values() as a generator be difficult?
>
> function generate_values(Traversable $in) {
>   foreach ($in as $k => $v) {
>     yield $k => $v;
>   }
> }
>
> In general, your `new Generator($arr)` concept misses most of the
> usefulness of using a generator since arrays are already traversable,
> and you've already allocated all the space of a full container.
> Where's the benefit from making it a generator?
>
> -Sara
>



-- 
David Rodrigues

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