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To: PHP Internals List <internals@lists.php.net>
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Date: Mon, 11 Jul 2016 22:20:39 +0100
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Subject: Re: [PHP-DEV] Proposal for php7 class method return
From: rowan.collins@gmail.com (Rowan Collins)

On 11/07/2016 21:17, Marco Pivetta wrote:
> On 11 July 2016 at 22:15, Rowan Collins <rowan.collins@gmail.com 
> <mailto:rowan.collins@gmail.com>> wrote:
>
>     Again, it's just different syntax for doing things we can already do.
>
>
> Spot on! Plus it's something arguably considered a bad idea. I don't 
> think that adding language features for this sort of thing is useful. 
> Maybe it's even just harmful.

Looking through the reasons given in your blog post, most of them don't 
really apply with a dedicated operator, because they're about the 
*contract*, and a cascade operator is only useful when the contract is 
to return something *other* than the current object.

Specifically, it relies on the assumption that the method is not 
returning a new instance. To adapt one of your examples:

$counter->count();
$counter->count();
$counter->count();
$counter->count();
echo $counter->getCount();
// This relies on count() mutating the current object, probably the 
contract is to return void

The same thing, with ->> as a cascade operator:

echo $counter
     ->>count()
     ->>count()
     ->>count()
     ->>count()
     ->getCount();

Or perhaps for clarity, pull the echo separately:

$counter
     ->>count()
     ->>count()
     ->>count()
     ->>count();
echo $counter->getCount();


The cascade operator is a tool to use *instead of* a fluent interface, 
not *with* it, and it solves a lot of the problems you outlined - 
$counter here can be mocked, wrapped, substituted for different 
implementations, etc, because the ->> operator makes no more assumptions 
than the code was already making.

Regards,

-- 
Rowan Collins
[IMSoP]