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
