ooc-dev team mailing list archive

[Amos Wenger <amoswenger@xxxxxxxxx>]

(damn Enter key that sends in GMail..)

The 'iterators are iterable' idiom is particularly useful in cases like
that:

selectWinners: func (clients: List<Client>) {
  iter := clients forward()
  deluxeLimit := 10
  winners := ArrayList<Client> new()
  losers := ArrayList<Client> new()

  for(c in iter) {
    winners add(c)
    if(winners size() >= deluxeLimit) break
  }

  // continue attributing people.
  for(c in iter) {
    losers add(c)
  }
}

Amos

On Fri, May 28, 2010 at 11:29 PM, Amos Wenger <amoswenger@xxxxxxxxx> wrote:

> Maybe we should have
>
>    - iterator()
>    - backIterator() (can throw exception if unsupported)
>    - forward() == iterator()
>    - backward() == backIterator() reverse()
>
> The 'iterators are iterable' idiom is particularly useful in cases like
> that:
>
> selectWinners: func (c: List<Clients>) {
> deluxeLimit := 10
>
>
> On Fri, May 28, 2010 at 10:20 PM, Noel Cower <ncower@xxxxxxxxx> wrote:
>
>> I like Josh and Rubin's ideas, although I think forward and backward don't
>> really communicate that the iterator is going to be at one end or the other
>> of the list.  Not all iterables are going to have the ability to go
>> forward/backward, so it would make sense, to me at least, to put those in
>> List, but then things like HashMap, which are iterable and can have reverse
>> iteration, won't have those methods.
>>
>> Maybe another subclass of Iterable is necessary to give List and HashMap
>> the same backing without having them be treated as different in terms of
>> their ability to iterate forwards/backwards?  Like BidirectionalIterable or
>> EndedIterable (the former being too long and the latter seems a little odd
>> to me).
>>
>> If we do use forward/backward, should backward always be a reverse
>> iterator?
>>
>> Also, iterable iterators sound nice, and I don't really see why we ought
>> to not do that - wouldn't cost anything, just have the iterator return
>> itself when iterator() is called.
>>
>>  -noel
>>
>> On May 28, 2010, at 9:48 AM, Amos Wenger wrote:
>>
>> I like the proposal of Rubin.
>>
>> Maybe iterator should be iterable? (they would just return themselves)
>>
>> In that case we could write:
>>
>> for(element in list backward())
>>>
>>
>> And ex-Java programmers could even write
>>
>> for(element in list forward())
>>>
>>
>> If they wanted.
>>
>> Amos
>>
>> On Fri, May 28, 2010 at 5:59 PM, cd rubin <launchpad@xxxxxxxxxxxxxxxx>wrote:
>>
>>>
>>> Hey all
>>>
>>> In which case shouldn't the methods be called 'forwards' and 'backwards'?
>>> I think that fits better with the language :
>>>
>>> "iterate over a list backwards"
>>>
>>> iter := list backwards()
>>>
>>> and it removes possible confusion stemming from calling the method
>>> 'front' and getting an iterator instead of the first item of the list!
>>>
>>>  - Daniel (cdrubin)
>>>
>>> On Fri, May 28, 2010 at 11:21 AM, Josh Roesslein <jroesslein@xxxxxxxxx>wrote:
>>>
>>>> Bart makes a good point that not all Iterables will have an ordered
>>>> structure (ex: socket input/output streams).
>>>> I think it would make more sense having front() and back() methods in
>>>> List that returns Iterators that either traverse
>>>> the list head to tail or vice versa.
>>>>
>>>> Josh
>>>>
>>>> On Fri, May 28, 2010 at 9:33 AM, Amos Wenger <amoswenger@xxxxxxxxx>wrote:
>>>>
>>>>> So what then? iterator~back() ?
>>>>>
>>>>>
>>>>> On Fri, May 28, 2010 at 2:53 PM, Bart van der Werf <bluelive@xxxxxxxxx
>>>>> > wrote:
>>>>>
>>>>>> I'm not sure.
>>>>>>
>>>>>> Alot of iterables have no order, so if front/back is the default way
>>>>>> to get an iterator it would make little sense.
>>>>>>
>>>>>
>>>>>
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>>
>