iteratee enumPair incorrectly propagating the stream

[Conrad Parker]

On 3 March 2011 17:40, John Lato <jwlato at gmail.com> wrote:
> Thanks very much for this patch.  It's definitely a better implementation
> than the old version and it's been pushed.
>
> I wonder if enum3, enum4, and enum5 would be better names than the
> spelled-out version.  It would be consistent with the "zip" functions.  And
> maybe enumPair should have its name changed also, maybe "enumZip", or just
> "eZip".  That would have to wait for a major release unfortunately, but the
> new name could be introduced now.
>
> Thoughts?  I'll put a new release on Hackage after I get some feedback about
> the names.

consistency would be good, eg.:

enum2, enum3, enum4 ...

or

enumZip, enumZip3, enumZip4 ...

also it would be worth noting in the documentation that enumSequence
is a similar operation over lists.

bikeshedding, I don't think eZip is very descriptive. OTOH if we want
short names to use qualified, perhaps just use zip, zip2, sequence
etc. (ie. I.zip, I.zip2, I.sequence ...)

Conrad.

>
> John
>
> On Thu, Mar 3, 2011 at 6:10 AM, Maciej Wos <maciej.wos at gmail.com> wrote:
>>
>> Hello,
>>
>> I've noticed that enumPair can behave a little strange. In some cases
>> it returns a part of the stream it has already consumed; this is tied
>> to the length of the chunk it is given:
>>
>> > run =<< I.enumPureNChunk [1..10 :: Int] 1 ((I.enumPair I.head (I.head >>
>> > I.head >> I.head)) >> I.stream2list)
>> [4,5,6,7,8,9,10]
>> > run =<< I.enumPureNChunk [1..10 :: Int] 2 ((I.enumPair I.head (I.head >>
>> > I.head >> I.head)) >> I.stream2list)
>> [4,5,6,7,8,9,10]
>> > run =<< I.enumPureNChunk [1..10 :: Int] 3 ((I.enumPair I.head (I.head >>
>> > I.head >> I.head)) >> I.stream2list)
>> [2,3,4,5,6,7,8,9,10]
>> > run =<< I.enumPureNChunk [1..10 :: Int] 5 ((I.enumPair I.head (I.head >>
>> > I.head >> I.head)) >> I.stream2list)
>> [2,3,4,5,6,7,8,9,10]
>>
>> I found the implementation in the library hard to follow, so I written
>> a new version from scratch. I also added enumThree, enumFour and
>> enumFive for a good measure -- I've used something like enumFive in my
>> code before and I think they would be nice to have.
>>
>> I've attached a patch with the changes.
>>
>> -- Maciej
>>
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>
>
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