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  • p

    pakoito

    10/17/2018, 10:20 AM
    I’ve added some tips already
  • j

    jacob

    10/17/2018, 12:24 PM
    Perfect, thanks! I'll shout out here when I think it's ready for a review
  • t

    tomasruizlopez

    10/19/2018, 1:41 PM
    @raulraja Sometimes it happens as well in Bow, the coverage report I get is quite different from the one I can see in Xcode, and so far I haven't been able to guess why
  • r

    raulraja

    10/19/2018, 1:45 PM
    ok, I’m gonna leave codecov as is and will merge anyway. Time for tech debt, I can’t hold this PR any longer because I’m blocking a bunch of people
  • r

    raulraja

    10/19/2018, 2:42 PM
  • r

    raulraja

    10/19/2018, 2:42 PM
    This improves syntax in Arrow a lot for all data types: ^^^
  • r

    raulraja

    10/19/2018, 2:43 PM
    For most use cases you can forget wrappers and for all data types you get projection of all the type class extension functions directly over the datatype when using the instances modules
  • r

    raulraja

    10/19/2018, 2:43 PM
    Copy code
    import arrow.instances.list.traverse.*

listOf(Some(1), Some(2)).sequence(Option.applicative()) 
// Some(listOf(1, 2))
    👏 2
    😍 1
  • r

    raulraja

    10/19/2018, 2:44 PM
    It removes the need to use the extension DSL 
    extensions { ... }
    which has been deprecated and you no longer need tu use 
    .run {...}
    to activate type class syntax unless you are in a polymorphic context already.
  • r

    raulraja

    10/19/2018, 2:45 PM
    The new 
    @extension
    annotation processor exports the syntax as extension functions in the package appropriately downcasting from the kinded version to the concrete one
  • s

    simon.vergauwen

    10/19/2018, 2:47 PM
    👏 👏 👏 amazing work!
  • r

    raulraja

    10/19/2018, 2:59 PM
    @simon.vergauwen I have not tested the improvements over optics directly but theoretically you can depend on the imports for types likes 
    ListK
    which now they are exported in 
    list
    too to improve the syntax generation for 
    Index
    at
    etc.
  • r

    raulraja

    10/19/2018, 2:59 PM
    so there is no need to wrap them in the 
    ListK.index
    for example
  • s

    simon.vergauwen

    10/19/2018, 4:38 PM
    What is the reason for moving it back?
  • r

    raulraja

    10/19/2018, 4:43 PM
    Every time we make an Arrow release Ank needs to be updated so the subsequent release can use Ank and it hasn’t in the last couple of releases in a timely fashion so it has been blocking us. Additionally Ank depends on Arrow but we need to figure out how to make 
    arrow-shadow
    which produces an uber jar to work with Kotlin. Once you import one of the 
    arrow-shadow
    snapshots in ank or arrow-meta which is the same problem we have no access to extension functions or generated code. Just basic data types. Once arrow-shadow works we can provide the optics DSL for arrow-meta and have Ank depend on shadowed version so the arrow version used with the snippets it’s not the same as the one the ank runtime uses.
  • s

    simon.vergauwen

    10/19/2018, 4:46 PM
    Alright cool. Thanks!
  • r

    raulraja

    10/20/2018, 2:55 PM
  • r

    raulraja

    10/20/2018, 9:01 PM
  • r

    raulraja

    10/20/2018, 10:57 PM
    Implementing monoid comprehensions I found a way to do something wild with a DSL over all type classes This works now:
    Copy code
    select<Int, Int> { it * 40 } from 1.just() where { it > 20 }
    It works polymorphically for any 
    Kind<F, A>
    in the FunctorFilter hierarchy of MTL as you go up the hirarchy you can add capabilities most of the query combinators can be done with Functor, FunctorFilter, Applicative and MonadCombine.
  • r

    raulraja

    10/20/2018, 11:00 PM
    What this mean for Arrow is that we can extract data from any data type with the same syntax: List, Option, etc. The more powerful the datatype the more combinators from the SQL style DSL will support. This will also work for all Kotlin Collections we support in Arrow including List, Set, Map, Sequence, etc.. since they are methods exported by the type class over all the types providing instances.
  • r

    raulraja

    10/20/2018, 11:01 PM
    select
    : Functor.map 
    from
    : Applicative.just or Applicative.product for 
    join
    `where`: FunctorFilter.filter
  • r

    raulraja

    10/20/2018, 11:02 PM
    Since it works over any kinded value this means that in the Future when we have integrations like Spark Data sets etc which are also kinded and can provide instances for those type classes you will be able to use the same DSL to reduce a list locally than you use to reduce a distributed remote data set.
    arrow 1
    😍 1
  • r

    raulraja

    10/20/2018, 11:06 PM
    It’s inspired in this post where monoid comprehensions are presented and the concept of Linq style queries and what that would look like in Arrow http://www.acidalie.com/monoid-comprehension.html
  • l

    Leandro Borges Ferreira

    10/22/2018, 11:49 PM
    Arrow could use https://github.com/bors-ng/bors-ng to manage the PRs queue. It is really hard to keep merging the Master branch in the PR so many times
  • l

    Leandro Borges Ferreira

    10/22/2018, 11:56 PM
    its free open source projets
  • p

    pakoito

    10/23/2018, 10:07 PM
  • p

    pakoito

    10/23/2018, 10:07 PM
    a quick stamp for consistency, please
  • r

    raulraja

    10/24/2018, 10:48 AM
    @Leandro Borges Ferreira The recent problems were related to https://github.com/arrow-kt/arrow/pull/1040 making tons of folder changes and relocation of instances so things started pilling up. The bot looks good though. If you want to give it a shot at integrating it we can take it from there and see how it works with our current flow.
  • p

    pakoito

    10/24/2018, 10:54 PM
  • p

    pakoito

    10/24/2018, 10:54 PM
    urgent, please, to merge tomorrow’s example so I can link it in the slides 🙂
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