śr., 27 cze 2018 o 16:55 Michał Brzuchalski <mic...@brzuchalski.com> napisał(a):
> > > śr., 27 cze 2018 o 03:29 Rudolf Theunissen <rudolf.theunis...@gmail.com> > napisał(a): > >> > I would like to see this in an extension first, i think it's perfectly >> doable and people can test it before merging to core >> >> > It was possible in Sara's extension[1], so maybe now also? Take a look. > > > >> Actually not sure this can be done as an extension because it changes >> zend_operators and introduces a new handler to make it all work. >> >> > Would be nice if compareTo and equals were used only if left operand and >> right operand used the same comparator function. >> In other words, $a == $b must not work if $a->__equals and $b->__equals >> are >> two different functions >> >> So effectively it means we only call __equals if both sides are instances >> of the same class? >> >> > If $left operand and $right operand both have the magic methods, it will >> call $left->__magic($right), otherwise, if only the right one has the >> handler? What if the right one has compareTo and the left has only equal? >> you probably should add a table that explains which method is called >> depending in the availability of the two magic methods in the operands. >> >> Good idea. :) In brief, as it's implemented right now, the LHS takes >> precedence and the RHS will be called if it's the only one that implements >> the operation. I'll write some more tests for these cases and build that >> table for the RFC. >> >> > I'd introduce a debug mode that forces php to call both >> $left->__equals($right) and $right->__equals($left) so that symmetry is >> guaranteed by design. >> >> If we want to guarantee symmetry by design, we have to either compare both >> sides or only compare if instances of the same class, or document that >> comparison should be implemented such that a > b == b < a, etc. I'm not >> convinced that a double comparison outweighs the responsibility on the >> user >> to be sensible. >> >> On Tue, 26 Jun 2018 at 21:04, Wes <netmo....@gmail.com> wrote: >> >> > some ideas and concerns: >> > >> > - I would like to see this in an extension first, i think it's perfectly >> > doable and people can test it before merging to core >> > >> > - would be nice if compareTo and equals were used only if left operand >> and >> > right operand used the same comparator function. >> > In other words, $a == $b must not work if $a->__equals and $b->__equals >> > are two different functions >> > >> > - otherwise RFC should specify the precedence. if $left operand and >> $right >> > operand both have the magic methods, it will call >> $left->__magic($right), >> > otherwise, if only the right one has the handler? >> > what if the right one has compareTo and the left has only equal? you >> > probably should add a table that explains which method is called >> depending >> > in the availability of the two magic methods in the operands. >> > >> > - I'd introduce a debug mode that forces php to call both >> > $left->__equals($right) and $right->__equals($left) so that symmetry is >> > guaranteed by design. You could do that when "assertions" are active. >> > >> > gl >> > >> > > [1] https://github.com/php/pecl-php-operator/blob/master/operator.c > -- > regards / pozdrawiam, > -- > Michał Brzuchalski > about.me/brzuchal > brzuchalski.com > There is also one more thing I can think of. If __equals and __compareTo methods don't have any restrictions for $other parameter typehint then I'll be able to declare Foo { public function __compareTo(int $other): int {} } and will get some error on new Foo() == new DateTime('now'); Right? -- regards / pozdrawiam, -- Michał Brzuchalski about.me/brzuchal brzuchalski.com
