Add divide typeclasses #1311

1Jajen1 · 2019-02-22T11:25:09Z

Partially solves #284 (Only the divide parts)

Again like stated in #1181 there some annoying parts:

The docs are there, I don't really like them, but could not come up with better text/examples 🙈
There are no laws for decidable atm, there are some here, but I don't really understand them well enough to attempt to port them :/ Scala cats and/or scalaz don't include them either afaik.
Some monad transformer instances are missing tests because we don't have instances that fulfill the constraints for them (don't really know what to do there)

Any ideas for better examples/texts do describe them? I'll think about it some more, but don't know if I can come up with something better :/

1Jajen1 · 2019-02-22T12:47:57Z

Hmm I don't think I understand the error ank throws here. It happens locally as well, but not when the code is just run in a standalone file (copy pasted over basically). I am confused :/

pakoito · 2019-02-22T17:43:50Z

I'll review this tonight or tomorrow!

pakoito · 2019-02-23T22:25:42Z

modules/core/arrow-test/src/main/kotlin/arrow/test/laws/DivideLaws.kt

+    cf: (Int) -> Kind<F, Int>,
+    EQ: Eq<Kind<F, Int>>
+  ): Unit =
+    forAll(Gen.int().map(cf)) { fa ->


Cute. I like it :)

pakoito · 2019-02-23T22:26:55Z

modules/core/arrow-test/src/main/kotlin/arrow/test/laws/DivideLaws.kt

+    EQ: Eq<Kind<F, Int>>
+  ): Unit =
+    forAll(Gen.int().map(cf)) { fa ->
+      EQ.run {


I believe this should use equalsUnderTheLaw instead of EQ directly.

pakoito · 2019-02-23T22:27:26Z

modules/core/arrow-test/src/main/kotlin/arrow/test/laws/DivisibleLaws.kt

+    EQ: Eq<Kind<F, Int>>
+  ): Unit =
+    forAll(Gen.int().map(cf)) { fa ->
+      EQ.run {


Same as above, equalsUnderTheLaw

pakoito · 2019-02-23T22:30:22Z

modules/core/arrow-typeclasses/src/main/kotlin/arrow/typeclasses/Decidable.kt

+ *
+ * fun main(args: Array<String>) {
+ *   //sampleStart
+ *   val stringOrInt: Serializer<Either<String, Int>> = Serializer.decidable()


Powerful shit.

pakoito · 2019-02-23T22:32:58Z

modules/core/arrow-typeclasses/src/main/kotlin/arrow/typeclasses/Decidable.kt

+    fh: Kind<F, H>,
+    fi: Kind<F, I>,
+    fj: Kind<F, J>,
+    f: (Z) -> Either<A, Either<B, Either<C, Either<D, Either<E, Either<FF, Either<G, Either<H, Either<I, J>>>>>>>>>


@raulraja is there any way of generalizing this for Product? Or convert between them?

pakoito · 2019-02-23T22:35:52Z

modules/core/arrow-typeclasses/src/main/kotlin/arrow/typeclasses/Divide.kt

+/**
+ * [Divide] is a typeclass that models the divide part of divide and conquer.
+ *
+ * [Divide] basically states: Given a Kind<F, A> and a Kind<F, B> and a way to turn C into an A and B it gives you a Kind<F, C>


into an A and B may be better phrased as a tuple of A and B, even if it's an implementation detail it's easy to miss.

pakoito · 2019-02-23T22:36:13Z

modules/core/arrow-typeclasses/src/main/kotlin/arrow/typeclasses/Divide.kt

+    val (a, b, c, d, e, fff, g, h, i, j) = f(it)
+    a toT Tuple9(b, c, d, e, fff, g, h, i, j)
+  }
+}


NIT: additional empty line

pakoito · 2019-02-23T22:37:10Z

modules/core/arrow-typeclasses/src/main/kotlin/arrow/typeclasses/Divide.kt

+    dummy6: Unit = Unit,
+    dummy7: Unit = Unit,
+    dummy8: Unit = Unit
+  ): Kind<F, Tuple10<A, B, C, D, E, FF, G, H, I, J>> =


RIP IntelliJ

I've done worse with a small project regarding generators for prop testing (generated ~1k lines of Tuple code for generating tuples and shrinkers for them) :) IntelliJ takes a while to load that file :D

pakoito · 2019-02-23T22:38:12Z

modules/docs/arrow-docs/docs/docs/arrow/typeclasses/divide/README.md

+beginner
+
+`Divide` is a typeclass that models the divide part of divide and conquer.
+`Divide` basically states: Given a `Kind<F, A>` and a `Kind<F, B>` and a way to turn `C` into an `A` and `B` it provides you a `Kind<F, C>`


Same as above, mention a coproduct or a tuple or something that helps with the association, else it's easy to miss.

pakoito

Really good job getting both parts of the hierarchy! 👏

Approving to unblock, but I'd like to see the fixes in the laws if possible.

1Jajen1 · 2019-02-23T23:04:07Z

WTF github I never clicked that

1Jajen1 · 2019-02-23T23:07:30Z

Done the small stuff.
Tests are missing for StateT (we have no monad that implements Divide etc) (although this may be possible with using like OptionT and Const like in their tests, which is already weird but might work) and Sum (again no comonads that implement divide etc)

1Jajen1 · 2019-02-23T23:40:25Z

Added a test for Sum. Now only StateT is missing, but since we have no instance that is Monad and Divisible that is kinda hard to do. (Function1 is almost it with Monad<Function1PartialOf<A>> but Divisible is defined as Divisible<Conested<ForFunction1, A>>)

1Jajen1 · 2019-02-24T00:01:29Z

So ank is being funny (or rather what executes the script). The code 100% compiles and runs fine but running in ank crashes with:
Backend Internal error: Exception during code generation Cause: Back-end (JVM) Internal error: Don't know how to generate outer expression: Class: class Companion Cause: Don't know how to generate outer expression: Class: class Companion File being compiled at position: (17,19) in /Line_1.kts The root cause was thrown at: CodegenContext.java:219 File being compiled at position: mock:///Line_1.kts The root cause was thrown at: ExpressionCodegen.java:319
Or another error related to type inference (which has no problems outside the script)
I don't really understand whats going on atm

pakoito · 2019-02-24T00:44:36Z

Do you know what file is that for?

1Jajen1 · 2019-02-24T01:05:35Z

Do you know what file is that for?

The scary internal error is for Decidable's README and the other type inference error happens for all snippets where Serializer's contramap is defined without this@contramap (every snippet in kdoc for divide etc)

pakoito · 2019-02-24T04:53:35Z

I'd move the setup code to the arrow-docs project instead. You'll probably get codegen right with it too.

pakoito · 2019-02-24T04:54:04Z

Here: https://github.com/arrow-kt/arrow/tree/master/modules/docs/arrow-docs/src/main/kotlin

1Jajen1 · 2019-02-24T14:02:26Z

Yeah this fixed it. Too bad the examples now cannot be viewed in full, but better than no examples at all

pakoito · 2019-02-24T15:02:02Z

modules/docs/arrow-docs/src/main/kotlin/DivideHelper.kt

@@ -0,0 +1,44 @@
+package com.example.domain


@1Jajen1 I didn't see this before merging. Could you please make it a nicer package?

1Jajen1 added 4 commits February 22, 2019 11:52

Add divide typeclasses and docs

eb3bb16

Fix detekt

795b13a

Fix broken test

e6b18a3

Fix snippet imports

b15cc6d

pakoito reviewed Feb 23, 2019

View reviewed changes

pakoito approved these changes Feb 23, 2019

View reviewed changes

Some pr fixes

5a1cff5

1Jajen1 closed this Feb 23, 2019

1Jajen1 reopened this Feb 23, 2019

Add Sum test

7af8284

Add typeclasses to intro page

30a162d

Fix snippets by moving serializer code away

2616abb

pakoito merged commit 456623b into arrow-kt:master Feb 24, 2019

pakoito reviewed Feb 24, 2019

View reviewed changes

This was referenced Feb 24, 2019

Add new typeclasses to sidebar #1314

Merged

Apply and Divide typeclasses #284

Closed

Add divide typeclasses #1311

Add divide typeclasses #1311

Uh oh!

Conversation

1Jajen1 commented Feb 22, 2019

Uh oh!

1Jajen1 commented Feb 22, 2019

Uh oh!

pakoito commented Feb 22, 2019

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

pakoito left a comment

Choose a reason for hiding this comment

Uh oh!

1Jajen1 commented Feb 23, 2019 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

1Jajen1 commented Feb 23, 2019

Uh oh!

1Jajen1 commented Feb 23, 2019

Uh oh!

1Jajen1 commented Feb 24, 2019 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

pakoito commented Feb 24, 2019

Uh oh!

1Jajen1 commented Feb 24, 2019

Uh oh!

pakoito commented Feb 24, 2019

Uh oh!

pakoito commented Feb 24, 2019

Uh oh!

1Jajen1 commented Feb 24, 2019

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Uh oh!

1Jajen1 commented Feb 23, 2019 •

edited

Loading

1Jajen1 commented Feb 24, 2019 •

edited

Loading