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Date: Sun, 10 Jul 2016 22:31:42 +1000
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To: Rasmus Schultz <rasmus@mindplay.dk>
Cc: Daniel Ciochiu <daniel@ciochiu.ro>, PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Proposal for php7 class method return
From: me@jesseschalken.com (Jesse Schalken)

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On Sun, Jul 10, 2016 at 8:34 PM, Rasmus Schultz <rasmus@mindplay.dk> wrote:

>
> What you're really trying to accomplish is something like the ".."
> operator found in some other languages - this is known as the "cascade
> operator" in Dart, for example:
>
>
> http://news.dartlang.org/2012/02/method-cascades-in-dart-posted-by-gilad.html
>
>

While I was writing about an operator to set object properties in-line
here: http://news.php.net/php.internals/93662 , I considered it would be
easy to add method calls to the same syntax:


return Blah::create(5) {
    prop1 = 'hello',
    prop2 = a_func(),
    setThing(9),
    setOtherThing(1),
};


which is in principle just an alternative syntax to as the cascade operator
in Dart.

I agree entirely that method chaining is just a verbose workaround for the
lack of such a language feature. I've found a few problems with method
chaining which this would resolve:

   1. The verbosity of adding "return $this;" to all your mutator methods
   (Daniel Ciochiu's issue).
   2. You can't return a value from a mutator method while also supporting
   method chaining. In theory mutator methods shouldn't need a return value
   (command-query separation) but in many cases they do, such as a setter
   which returns the previous value, a pop() method on a stack, or a
   delete($where) method returning the number of deleted records.
   3. It is often unclear whether a method being chained is returning the
   same object it was called on, a copy of the object, or an instance of a
   different class altogether. You can work around this with careful method
   naming and documentation ("with.." for new instance, "set.." for same
   instance etc), but language-level support eliminates this issue entirely.

You could really solve a whole range of problems with such a feature.

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