Stanislav wrote:
I think "as long as it is not overused" are the key words there. We
have a very limited number of internal classes with operator
overloading
I think the whole point of leaving it to extensions was ensuring it's
not overused. And now I see people arguing "well, if it's available to
extensions, then it also must be available to userspace" - which is
the reverse of the premise under which it was implemented in the first
place. Once we open this door, there's nothing that would prevent
overuse and abuse - in fact, as we see, even having this door closed
leads people to think since it exists, it must be used to the maximum,
addition of userspace operator overloading will surely be taken as
encouragement to be as creative as possible with overloading operators
and inventing all kinds of incomprehensible and inconsistent operator
schemes because it looked cool at the moment. So if anybody has hope
it would "not be overused" - it will be.
C++ has a philosophy: "Trust the programmer." [1] While I understand that
many are not amused by the overloading of ">>" and "<<" to mean input and
output, the larger issue is that using such stream operators and function
overloading provides an elegant and extensible way of providing reading and
writing of user-defined types, usable for any stream.
I know PHP is not C++, but other languages has been mentioned in this context,
and another core tenet of the C++ language is that it's more important to
provide useful abstractions, rather than banning anything that may be misused.
Let's face it, you could make "add()" _subtract_ the numbers, or do strange
things, just as well as you could do with a function overloading "+".
Personally, I find it a greater gain in terms of code clarity to be able
to write e.g.:
$result = $a + $b * $c + $d;
rather than:
$result = $a->add($b->multiply($c))->add($d);
Quick: Is the second one exactly identical to the first one?
Yes, it is, but this one's got the associativity wrong:
$result = $a->add($b)->multiply($c)->add($d);
Would you catch that in code?
There's a reason mathematicians have invented a set of symbols: It makes
it easier to comprehend code using it, than if you only use function notation.
We already know how to mentally parse expressions in terms of operator precedence,
and having operator overloading follow the same rules means we can use that
skill also for user-defined types.
Regards,
Terje
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