RE: [PHP-DEV] Re: [VOTE] Userspace operator overloading

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  109340
March 26, 2020 16:37 jan.h.boehmer@gmx.de
On Thursday, March 26, 2020 3:50 AM Jakob Givoni <jakob@givoni.dk> wrote:

> On Wed, Mar 25, 2020 at 6:28 AM Christoph M. Becker <cmbecker69@gmx.de> wrote: > >> It seems to me that the RFC is not sufficiently specific enough >> regarding the concatenation of instances of classes which implement >> __toString(). > > Exactly what I was thinking too. Would be nice with some examples on this.
I am not sure if I can (or should) still add this to the RFC, here some clarification on this: The overloaded concat operator has higher priority than the __toString() method. So if Class A overloades the concat operator, then calling $a . $b means ClassA::__concat($a, $b); (Note that both operands are passed in their original form) If you want to concat the string representations, you will have to explicitly convert the objects to strings: $ret = (string) $a . (string) $b; If the concat operator is not overloaded, the behavior is like now, and the objects are converted implicitly to strings (so $a . $b actually means (string) $a . (string) $b). Furthermore an notice is triggered, hinting the user that he could overload the concat operator. (Maybe here a different message than for the other operators would be useful).
  109345
March 26, 2020 17:18 guilliam.xavier@gmail.com (Guilliam Xavier)
On Thu, Mar 26, 2020 at 5:37 PM boehmer@gmx.de> wrote:
> > The overloaded concat operator has higher priority than the __toString() method. > So if Class A overloades the concat operator, then calling $a . $b means ClassA::__concat($a, $b); (Note that both operands are passed in their original form) > If you want to concat the string representations, you will have to explicitly convert the objects to strings: > $ret = (string) $a . (string) $b;
This first part seems legit to me.
> If the concat operator is not overloaded, the behavior is like now, and the objects are converted implicitly to strings (so $a . $b actually means (string) $a . (string) $b). > Furthermore an notice is triggered, hinting the user that he could overload the concat operator. (Maybe here a different message than for the other operators would be useful).
I fear that "hint" notice could break Symfony apps... Couldn't you just not trigger it in this case? -- Guilliam Xavier
  109346
March 26, 2020 17:25 cmbecker69@gmx.de ("Christoph M. Becker")
On 26.03.2020 at 18:18, Guilliam Xavier wrote:

> On Thu, Mar 26, 2020 at 5:37 PM boehmer@gmx.de> wrote: >> >> The overloaded concat operator has higher priority than the __toString() method. >> So if Class A overloades the concat operator, then calling $a . $b means ClassA::__concat($a, $b); (Note that both operands are passed in their original form) >> If you want to concat the string representations, you will have to explicitly convert the objects to strings: >> $ret = (string) $a . (string) $b; > > This first part seems legit to me. > >> If the concat operator is not overloaded, the behavior is like now, and the objects are converted implicitly to strings (so $a . $b actually means (string) $a . (string) $b). >> Furthermore an notice is triggered, hinting the user that he could overload the concat operator. (Maybe here a different message than for the other operators would be useful). > > I fear that "hint" notice could break Symfony apps... Couldn't you > just not trigger it in this case?
Either that (it's what I would prefer), or clearly document that BC break (even if it's just about a notice). Thanks, Christoph
  109347
March 26, 2020 17:36 jan.h.boehmer@gmx.de
On Thursday, March 26, 2020 6:19 PM Guilliam Xavier xavier@gmail.com> wrote:

>> If the concat operator is not overloaded, the behavior is like now, and the objects are converted implicitly to strings (so $a . $b actually means (string) $a . (string) $b). >> Furthermore an notice is triggered, hinting the user that he could overload the concat operator. (Maybe here a different message than for the other operators would be useful). > > I fear that "hint" notice could break Symfony apps... Couldn't you just not trigger it in this case?
Yes this would be possible and I think that it might be reasonable to omit the notice in this case (maybe only if the objects really implement a __toString). What do others think about this? Regards, Jan