2015-01-30 18:07 GMT+03:00 Andrea Faulds <a...@ajf.me>:
> This approach wouldn’t solve the problem you’re describing. You *still*
> need to produce a new request object, because the request object is
> immutable. The mutability of its *properties* isn’t the issue.
Thank you for this answer. However, pay an attention to the last part of my
suggestion. To create a mutable copy of immutable object it will be
possible just to make an assignment (this will create a copy/clone) to a
local mutable variable and adjust it for your needs.
example:
public function handleRequest(const Request $request) { // Mark $request as
immutable for body
// we can not change $request variable itself
// but if need, we can only initialize a copy of it
// $request->url = 'https://evil.com'; // Exception will be there
$mutableSubRequest = $request; // copy of immutable object or maybe a
direct Copy-on-Write?
$mutableSubRequest->uri = 'https://example.com'; // It's ok to modify
our local copy of an object
$this->kernel->handleRequest($mutableSubRequest);
}
2015-01-30 18:07 GMT+03:00 Andrea Faulds <a...@ajf.me>:
> Hi Alexander,
>
> > On 30 Jan 2015, at 13:07, Alexander Lisachenko <lisachenko...@gmail.com>
> wrote:
> >
> > Hello, internals!
> >
> > Today I was looking at PSR-7 and discovered this part of code:
> >
> > $body = new StringStream(json_encode(['tasks' => [
> > 'Code',
> > 'Coffee',
> > ]]));;
> > $request = $baseRequest
> > ->withUri($uri->withPath('/tasks/user/' . $userId))
> > ->withMethod('POST')
> > ->withHeader('Content-Type' => 'application/json')
> > ->withBody($body);
> > $response = $client->send($request);
> >
> > What is wrong here? Emulated immutability. All methods will create a
> > separate instance of request, so
> > $baseRequest->withUri()->withMethod()->withHeader()->withBody() will
> create
> > total 5 object instances. It's a memory overhead and time consumption for
> > each method call.
>
> Yes, I also think this is unfortunate.
>
> > What I want to discuss is true immutability flag for variables and
> > parameters. There are a lot of languages that use "final" or "const"
> > keywords to prevent modification of variables. We can use this approach
> by
> > extending language syntax as following:
>
> This approach wouldn’t solve the problem you’re describing. You *still*
> need to produce a new request object, because the request object is
> immutable. The mutability of its *properties* isn’t the issue.
>
> If you want to avoid creating five different objects, you’d need to
> implement value-type objects that are passed by value and use
> copy-on-write. Basically, you’d need to re-add PHP 4 style classes.
>
> Thanks.
> --
> Andrea Faulds
> http://ajf.me/
>
>
>
>
>
