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Date: Thu, 27 Nov 2025 10:08:14 +0100
To: "Rowan Tommins [IMSoP]" <imsop.php@rwec.co.uk>
Cc: internals@lists.php.net
Subject: Re: [PHP-DEV] Examples comparing Block Scoped RAII and Context
 Managers
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From: tim@bastelstu.be (=?UTF-8?Q?Tim_D=C3=BCsterhus?=)

Hi

Am 2025-11-19 23:19, schrieb Rowan Tommins [IMSoP]:
> On 18/11/2025 17:23, Larry Garfield wrote:
>> One thing I definitely do not like is the need for a `FileWrapper` 
>> class in the RAII file-handle example.  That seems like an unnecessary 
>> level of abstraction just to squeeze the `fclose()` value onto the 
>> file handle.  The fully-separated Context Manager seems a more 
>> flexible approach.
> 
> 
> Yes, exploring how exactly that flexibility could be used was part of 
> my motivation for the examples I picked.
> 
> The downside is that it is slightly harder to understand at first 
> glance: someone reading "using (file_for_write('file.txt') as $fh)" 
> might well assume that $fh is the value returned from 
> "file_for_write('file.txt')", rather than the value returned from 
> "file_for_write('file.txt')->enterContext()".
> 
> What made sense to me was comparing to an Iterator that only goes 
> around once - in "foreach (files_to_write_to() as $fh)", the 
> "files_to_write_to()" call doesn't return $fh either, 
> "files_to_write_to()->current()" does.

For me the relevant keyword that indicates that the value is not used 
directly is not the 'as', but the 'each' part of the 'foreach'. Just by 
reading it as a English sentence, it becomes clear to me what is 
happening.

The same is not true for me for `using (file_for_write('file.txt') as 
$fh)` or even worse `using (new Manager() as $notActuallyTheManager)` 
(which is part of the RFC). AFAICT the latter is not so much a problem 
in Python, because there is no difference between constructors and 
factory functions and also because there is no actual type declaration. 
This means `open()` could be a function returning a file handle or it 
could be the “constructor“ for a context manager (that then returns the 
file handle as part of entering the context) and the difference is 
effectively indistinguishable from the outside, which is not the case in 
PHP.

Best regards
Tim Düsterhus