please merge 🙂 https://github.com/arrow-kt/Category-Theory-for-Programmers.kt/pull/37

In case anyone wants to help making ank being able to run kapt on code snippets. This would allows us to not keep separate helper files and we can use annotations in kdocs snippets too. https://kotlinlang.slack.com/archives/C0BT46EL8/p1552666063074100?thread_ts=1552133834.049300&cid=C0BT46EL8

I looked into this a year ago. I also dove into the Kotlin compiler and messed around with the mentioned classes

At one point I had a working version of it to compile snippets. Not sure where I left it with kapt but I remember I abandoned it 😄

IO can't provide an empty value and it's not ok bailing with an exception. That is why IO can't provide an instance for FunctorFilter

OptionT<ForIO, A>

can though

what we need is AQL extensions there for OptionT, EitherT and Kleisli

Alternatively for data types like IO where we want to enable

where

we could have an alternate AQL combinator

where { bool } orRaise { ex }

in a

WhereOr<E, A>

type class that types like

Either

and

IO

could implement letting the user specify

E

What is not Ok is to silently raise an arbitrary exception inside IO when a predicate is not found but if we give the user control we can be as expressive as needed and have other data types benefits from it.

We don't even have yet

chain

and other possible AQL combinators we can add for all monads but as it stands now,

IO

can't provide an extension for

Where

.

An alternative

WhereOr

type class will open AQL to even more data types like Validated etc which at the moment aren't able to.

Some hope for better effects error messages https://youtrack.jetbrains.com/issue/KT-29519

We may be able to fix the dokka issue where we are not getting proper links cross modules in the Arrow docs. In case anyone wants to help https://kotlinlang.slack.com/archives/C0F4UNJET/p1553030763027200?thread_ts=1551819905.008100&cid=C0F4UNJET

Simon is referencing there how we can link the projects

It packs DI, Custom error handling, throwable handling and IO effect suspension all in one efficient datatype defined over

suspend

functions with an underlying effect aware runtime and event loop that is going to be stacksafe and performant. Additionally allows you to describe entire architectures just as pure functions and suspended effects. Supports concurrency out of the box and implements the Effects type classes so you can run your programs thanks to Arrow's polymorphism to any framework. It complements and is comptaible with

coroutines-core

based programs and adds extra layers of safety atop the coroutines

async/await

model generalized and stack safe for all monad capable data types. https://gist.github.com/raulraja/0088c4d41c3fdcf5aa77e73316f4af22 If you've followed John De Goes latest work on Evironment + Zio. This is the Kotlin version of it which we had already supported before through the typeclassless technique pioneered by @pakoito and the Reader/Kleisli types but not over

suspend

. The future of Arrow effects is

suspend

and pure imperative syntax for effects based programs.

I got ank and kapt kinda working here: https://github.com/jereksel/ank2, but KT-25652 was major issue for me.

Need some Help: https://github.com/arrow-kt/Category-Theory-for-Programmers.kt/pull/38

@sam Thanks so much for merging https://github.com/kotlintest/kotlintest/pull/719 !

This will simplify many of the arrow tests and derived projects where we depend on KotlinTest

You're welcome. It will go into either 3.4 or 4.0 whatever we end up calling it.

I can't get it to use kapt with multi platform build at the moment hence the build is red

Does kapt not run on MPP?

if we can't figure it out we can add the boilerplate manually

It should in your Java part, no?

The classes and codegen should be cross platform compatible what I'm not sure is it kapt is JVM only for whatever limitation

kapt hooks into the java compiler for annotation processing right?

Yeah, kapt only transforms .kt to stubs nowadays, right?

yes

AFAIK that is why I think it should work unless we are using types or symbols not available

@sam do you have a link to the CI build where it is failing?