I believe the correct solution to this is an OuterIterator — an OuterIterator contains the logic to constrain the loop, for example, we have the LimitIterator, FilterIterator, RegexIterator, etc.
See this example: http://php.net/manual/en/class.limititerator.php#example-4473 You can build your own OuterIterators, which implements whatever logic your Reader should have. OuterIterators are also compose-able, you can stack them, though of course there are performance considerations here. I would say that any alternative to OuterIterator's should have a clear and demonstrable benefit in both developer experience, and performance before it should be considered. - Davey On Wed, Jul 5, 2017 at 3:51 AM, Rowan Collins <rowan.coll...@gmail.com> wrote: > On 3 July 2017 16:58:16 BST, Andreas Hennings <andr...@dqxtech.net> wrote: > >My motivation was to be able to use iterators and readers > >interchangeably. > >Readers are easier to implement as classes. > >Iterators have the benefit of the generator syntax. > >The idea is to have a library where some stuff is implemented as > >reader classes, and some other things are implemented as iterator > >classes. > > > >Then for the actual operational code, I need to choose to use either > >iterator syntax or reader syntax. So either I need adapters for all > >iterators, or I need adapters for all readers. > > An alternative to adapters in this case might be a Trait that allows you > to write the class as a Reader, but turn it into a fully-functioning > Iterator with one line of code. If you always call your read method read() > you only need a single adapter which calls that at the appropriate times > and buffers the value to know if it's reached the end. That adapter could > be "pasted" by a Trait into each class where read() is defined, and read() > could even be private. > > Regards, > > -- > Rowan Collins > [IMSoP] > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php >
