Re: Questions regarding DateTimeImmutable

Hey, would it be possible for DateTime and DateTimeImmutable to not extend each other at all and be two seperate classes? greetings, Benjamin On Sun, Feb 17, 2013 at 12:30 AM, Stas Malyshev <smalyshev@sugarcrm.com>wrote: > Hi! > > > a) The DateTimeImmutable class extends the DateTime class. Why was this > > done this way? Both classes are incompatible (as in the inheritance > > They're not really "incompatible". Functions that do not modify dates > would work just fine. So it's "not 100% compatible", which is not the > same as incompatible. Of course, we could instead create > DateTimeBaseAbstractClass, but IMHO rewriting all your code to support > it wouldn't be worth the trouble for 99.9% of the code, so what would > end up happening that nobody could use DateTimeImmutable with any > existing code that expects DateTime. I personally don't see much point > in DateTimeImmutable anyway (immutable data structures are very > important for concurrent programs but for PHP I don't see much benefit) > but if people need it, fine. But ask yourself a question - do you really > want to rewrite every library that accepts DateTime as an argument in > order to use DateTimeImmutable? > > > b) The DateTimeImmutable class is (method-wise) an exact copy of > DateTime. > > This makes for some rather weird method names for an immutable object. > E.g. > > there is DateTimeImmutable::modify, which to me seems quite > contradictory. > > There are also a lot of methods of the DateTimeImmutable::setTime form, > > which also seems rather odd and confusing (how can I set something on an > > immutable object?) > > I don't see how it's so hard to grasp - it sets time and returns the > modified object. I can't believe you genuinely don't understand how it > works. I have a feeling this "confusing" argument in getting somewhat > stale: PHP users - especially those that want to use specially designed > classes that are useable only in context of design of non-trivial > complexity - have sufficient brain capacity to understand what setTime > could do. And if they absolutely can't, they can to the unthinkable - > read the manual. > So I can see the LSP argument - but "confusing" argument really doesn't > seem to apply here. > -- > Stanislav Malyshev, Software Architect > SugarCRM: http://www.sugarcrm.com/ > (408)454-6900 ext. 227 > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php > >