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/
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