Another symmetry I was aiming for:
...select(tail, 'a')
...select('a').by(unfold.tail(1))
On Thu, Jun 11, 2015 at 2:16 PM, Matt Frantz <[email protected]>
wrote:
> I was trying to reconcile the way that the range/limit/tail steps operate
> with how Pop is interpreted. For local scope, the range ordinals are
> congruent with the list index ordinals. Thus, "limit(1)" means
> "range(0,1)" which means List.get(0). Since "tail(1)" is the complement of
> "limit(1)", it means "the highest numbered element" or
> List.get(List.size()-1).
>
> I understand your description of a stream, but I was trying to reconcile
> the terms with Gremlin and not with streams.
>
> If you compare a stream with a Unix command line, and how the "head" and
> "tail" utilities act, then "head" means "the first lines you see" and
> "tail" means "the last lines you see".
>
> For global scope, it seems that "limit(1)" means "the first traverser" and
> "tail(1)" means "the last traverser". For any Traversal, t, t.limit(1)
> produces the same thing as t.toList().get(0).
>
> Good news on select(pop)!
>
> On Thu, Jun 11, 2015 at 11:43 AM, Marko Rodriguez <[email protected]>
> wrote:
>
>> Hey,
>>
>> Yes -- "first = tail" and "last = head".
>>
>> A path grows with its "head growing" .. its tail is static.
>>
>> a-->b-->c-->d-->e
>>
>> the tail is always "a"…the head is "a", then "b", then "c", then "d"….
>>
>> In a list or stream, the tail is the first element.
>> - get(0) for list
>> - stream().toList().get(0)
>> In a list or stream, the head is always the most current element.
>> - get(list.size() - 1) for list
>> - stream().next()
>>
>> …..?
>>
>> I will hide your interface inside ImmutablePath just for my sanity :).
>>
>> BTW: select(pop) is on its way.
>>
>> Marko.
>>
>> http://markorodriguez.com
>>
>> On Jun 11, 2015, at 12:30 PM, Matt Frantz <[email protected]>
>> wrote:
>>
>> > limit(1) means "first" and tail(1) means "last" (in both global and
>> local
>> > manifestations).
>> >
>> > In the Path.get results, you get a list whose first element is the
>> > first/oldest object matching the step label, so that felt like "head" to
>> > me, while the last element is the most recent and thus "tail".
>> >
>> > get => [a,b,c,d]
>> > getSingle(head) => a
>> > getSingle(tail) => d
>> >
>> > In other words the following should be equal:
>> >
>> > ...map{it->it.path().get('foo')}.tail(local, 1)
>> > ...map{it->it.path().getSingle(tail, 'foo')}
>> >
>> > I used ImmutablePathImpl because I needed HeadPath to have the
>> > getSingleTail/getSingleHead methods, too. Thus, a common interface
>> between
>> > ImmutablePath and HeadPath was required. The interface has package
>> scope,
>> > so it is not part of the public API.
>> >
>> > On Thu, Jun 11, 2015 at 11:12 AM, Marko Rodriguez <[email protected]
>> >
>> > wrote:
>> >
>> >> Hi Matt,
>> >>
>> >> limit(1) means the most recent value.
>> >> tail(1) means the oldest value. ?
>> >>
>> >> path: [a,b,c,d]
>> >> a = tail
>> >> d = head
>> >>
>> >> No?
>> >>
>> >> Also, why did you do ImmutablePathImpl? Seems that can just be private
>> >> methods inside of ImmutablePath?
>> >>
>> >> Thanks,
>> >> Marko.
>> >>
>> >> http://markorodriguez.com
>> >>
>> >> On Jun 11, 2015, at 11:56 AM, mhfrantz <[email protected]> wrote:
>> >>
>> >>> GitHub user mhfrantz opened a pull request:
>> >>>
>> >>> https://github.com/apache/incubator-tinkerpop/pull/76
>> >>>
>> >>> TINKERPOP3-700 Path getSingle/getList improvements
>> >>>
>> >>> As requested in the comments of TINKERPOP3-700. I also reversed the
>> >> sense of `Pop` to align with `tail(local)`. Thus `Pop.tail` now means
>> the
>> >> most recent value.
>> >>>
>> >>> You can merge this pull request into a Git repository by running:
>> >>>
>> >>> $ git pull https://github.com/RedSeal-co/incubator-tinkerpop
>> >> TINKERPOP3-700-Path-getSingle
>> >>>
>> >>> Alternatively you can review and apply these changes as the patch at:
>> >>>
>> >>> https://github.com/apache/incubator-tinkerpop/pull/76.patch
>> >>>
>> >>> To close this pull request, make a commit to your master/trunk branch
>> >>> with (at least) the following in the commit message:
>> >>>
>> >>> This closes #76
>> >>>
>> >>> ----
>> >>> commit e1e1a40b068ffe6da3d321256d6200dee0504074
>> >>> Author: mhfrantz <[email protected]>
>> >>> Date: 2015-06-11T16:47:41Z
>> >>>
>> >>> Add javadoc for Path getList/getSingle
>> >>>
>> >>> commit 4939cf0a22c4fc44a4f86ed3e023fa30e4e872cc
>> >>> Author: mhfrantz <[email protected]>
>> >>> Date: 2015-06-11T17:10:27Z
>> >>>
>> >>> Reverse sense of Path.getSingle Pop to align with tail(local) step
>> >>>
>> >>> commit 027d6319f9ff06ca26d785e83bf17b21364c3dca
>> >>> Author: mhfrantz <[email protected]>
>> >>> Date: 2015-06-11T17:51:23Z
>> >>>
>> >>> Optimize MutablePath.getSingle
>> >>>
>> >>> commit 5e9ad8d7dff6c63b9746147a1d255cbf7258cea3
>> >>> Author: mhfrantz <[email protected]>
>> >>> Date: 2015-06-11T17:52:43Z
>> >>>
>> >>> Optimize ImmutablePath getSingle and getList
>> >>>
>> >>> ----
>> >>>
>> >>>
>> >>> ---
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>> >>
>> >>
>>
>>
>
