raulraja

{-# LANGUAGE DeriveFunctor #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE OverlappingInstances #-}

module Main where

import Control.Monad.Free

raulraja

package demo

import arrow.core.Either
import arrow.core.None
import arrow.core.Option
import arrow.core.Some
import arrow.core.continuations.Raise
import arrow.core.continuations.effect
import arrow.core.continuations.either
import arrow.core.continuations.toEither

raulraja

package org.coral.fp.control

import arrow.core.ValidatedNel
import arrow.core.invalidNel
import arrow.core.validNel
import arrow.core.zip
import kotlin.jvm.JvmInline

@JvmInline
public value class ProductId private constructor(public val value: Int) {

raulraja

Pre-SIP: Suspended functions and continuations in Scala 3.

This Pre-SIP post proposes continuations as a new language feature in Scala 3.

It has been prepared by Jack Viers, Raul Raja and reviewed by the Scala 3 team at 47 Degrees. This doc is intended to be used as a way to gather community feedback and foster discussion.

Motivation

Our observation in the industry and among our peers is that most programming in Scala today that involves async or I/O-based programs targets a monadic indirect boxed style.

raulraja

package examples

import arrow.core.Either
import arrow.core.continuations.EffectScope
import arrow.core.continuations.either

object Request
object Response
sealed interface Error
object InvalidRequest : Error

raulraja

package arrow.meta.continuations

import arrow.core.Either
import arrow.core.computations.either
import arrow.core.flatMap

/**
 * Models errors as values
 */
sealed interface Failure

raulraja

package arrow.core

public fun interface Partial<A, B, C, D, Z> {
  public operator fun invoke(a: A, b: B, c: C, d: D): Z

  public fun first(a: A): Partial<Unit, B, C, D, Z> =
    Partial { _, b, c, d -> invoke(a, b, c, d) }

  public fun second(b: B): Partial<A, Unit, C, D, Z> =
    Partial { a, _, c, d -> invoke(a, b, c, d) }

raulraja

package com.fortyseven.fptraining

import arrow.core.Either
import arrow.core.right
import arrow.effects.IO
import arrow.effects.extensions.io.fx.fx

data class Account(val balance: Int)
data class AccountEntity(val balance: Int)

raulraja

package arrow.derive

/**
 * An Algebraic data type [Type] can derive behaviors
 * for its members
 */
sealed class Derive<in Type> {
  /**
   * Derived instances associated to [Type]
   */

raulraja

Given validation steps

1. Only top level class, object, property or function can be @Given declarations

@Given fun <T> et(@Given eq: Eq<T>): Eq<Tree<T>> = ...

2. Declarations with Value parameters annotated as @Given for injection must