Ben Hutchison benhutchison
benhutchison
/ contravariant.scala
Created
October 31, 2012 01:38
— forked from eed3si9n/contravariant.scala
implementation of Equal typeclass using contravariance - difficulties resolved
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| object Test extends App { | |
| trait CanEqual[-A] { | |
| def equals(a1: A, a2: A): Boolean | |
| } | |
| object CanEqual { | |
| def apply[A](implicit ev: CanEqual[A]): CanEqual[A] = ev | |
| def equals[A](f: (A, A) => Boolean): CanEqual[A] = new CanEqual[A] { | |
| def equals(a1: A, a2: A): Boolean = f(a1, a2) | |
| } |
benhutchison
/ initScalajsCrossProject.sh
Last active
August 29, 2015 14:07
Script to init a new Scala JS/JVM cross-built project with an Intellij friendly layout. After running, just Open the directory in Intellij and Import. Uses https://github.com/lihaoyi/utest#jscrossbuild
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| #!/bin/bash | |
| [ $# -eq 0 ] && { echo "Usage: $0 <projectName>"; exit 1; } | |
| PROJECT=$1 | |
| echo "Creating project in ./$PROJECT" | |
| mkdir -p $PROJECT/{js,jvm,project} | |
| mkdir -p $PROJECT/shared/src/{main,test}/{scala,resources} | |
| cd $PROJECT |
benhutchison
/ HalResource.scala
Last active
August 29, 2015 14:15
— forked from mmollaverdi/HalResource.scala
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| // The following, models a HAL Resource based on HAL specification: | |
| // http://stateless.co/hal_specification.html | |
| // And provides Argonaut JSON encoders for that model | |
| // (Argonaut is a purely functional Scala JSON library) | |
| // http://argonaut.io/ | |
| import shapeless._ | |
| import shapeless.ops.hlist.{ToTraversable, Mapper} | |
| import argonaut._, Argonaut._ | |
| import scala.language.existentials | |
| import scala.language.higherKinds |
benhutchison
/ gist:9a1b6d891211ea18d699
Created
April 23, 2015 06:18
Property-based test of Queue.cycle(n: Int)
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| package com.github.benhutchison.richutil | |
| import org.specs2.ScalaCheck | |
| import org.specs2.mutable.Specification | |
| import org.scalacheck.Arbitrary | |
| import spire.math.Natural | |
| class QueueUtilSpec extends Specification with ScalaCheck { | |
| import collection.immutable.Queue | |
| import ScalacheckIntegration._ |
benhutchison
/ FirstNonEmpty-MonoidLawCheck-AmmoniteRepl
Created
February 11, 2016 13:04
Is the firstNonEmpty Monoid lawful? Lets get an opinion from the LawBot that Cats & friends use...
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| Welcome to the Ammonite Repl 0.5.1 | |
| (Scala 2.11.7 Java 1.8.0_66) | |
| ben_hutchison-ben_hutchison@ load.ivy("org.typelevel" %% "cats" % "0.4.1") | |
| ben_hutchison-ben_hutchison@ load.ivy("org.typelevel" %% "alleycats-core" % "0.1.3") | |
| ben_hutchison-ben_hutchison@ import cats._, cats.std.all._ | |
| import cats._, cats.std.all._ | |
| ben_hutchison-ben_hutchison@ import alleycats._ | |
| import alleycats._ |
benhutchison
/ Ammonite Repl session
Last active
August 16, 2016 12:11
Shapeless Poly woes when combining default case with case over sealed hierarchy (and a solution)
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| Welcome to the Ammonite Repl 0.5.2 | |
| (Scala 2.11.7 Java 1.8.0_51) | |
| @ load.ivy("com.chuusai" %% "shapeless" % "2.2.5") | |
| @ import shapeless._ | |
| import shapeless._ | |
| @ sealed trait Country | |
| defined trait Country | |
| @ case object Germany extends Country | |
| defined object Germany |
benhutchison
/ EffPlay.scala
Last active
April 26, 2016 08:20
Playing with Eff [https://github.com/atnos-org/eff-cats]. Discovered a cute syntax where effects can be written as context-bounds on the stack type (eg `def rollDice[E: RNG: Log]`). Also, burned some time discovering that type aliases seem essential when defining effect stacks.
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| import org.atnos.eff._ | |
| import cats.syntax.all._ | |
| import cats.data._ | |
| import Eff._ | |
| object EffPlay extends App { | |
| import Effects._ | |
| import WriterEffect._ | |
| import ReaderEffect._ |
benhutchison
/ sbtsession
Created
May 1, 2016 02:32
bench:compile problems in https://github.com/benhutchison/eff-cats/tree/topic/scalajs
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| > effJVM/bench:compile | |
| [warn] Credentials file /Users/ben/.sbt/specs2.credentials does not exist | |
| [info] Updating {file:/Users/ben/others-code/eff-cats/}effJVM... | |
| [info] Resolving jline#jline;2.12.1 ... | |
| [info] Done updating. | |
| [info] Compiling 1 Scala source to /Users/ben/others-code/eff-cats/jvm/target/scala-2.11/bench-classes... | |
| [error] /Users/ben/others-code/eff-cats/jvm/src/bench/scala/EffBenchmark.scala:21: type mismatch; | |
| [error] found : scalaz.Name[V] | |
| [error] required: org.atnos.eff.EvalEffect.Eval[?] | |
| [error] (which expands to) cats.Eval[?] |
benhutchison
/ gist:9353b7ff96ace04f488f7fb884c8b7e1
Created
June 20, 2016 23:37
Alleycats SBT> whatDependsOn Scalacheck 0.12.x vs 0.13.x
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| > testsJVM/whatDependsOn org.scalacheck scalacheck_2.11 1.12.5 | |
| [info] org.scalacheck:scalacheck_2.11:1.12.5 (evicted by: 1.13.1) | |
| [info] +-org.spire-math:algebra-laws_2.11:0.4.2 [S] | |
| [info] | +-org.typelevel:cats-laws_2.11:0.5.0 [S] | |
| [info] | +-org.typelevel:alleycats-laws_2.11:0.1.6-SNAPSHOT [S] | |
| [info] | +-org.typelevel:alleycats-tests_2.11:0.1.6-SNAPSHOT [S] | |
| [info] | | |
| [info] +-org.typelevel:alleycats-laws_2.11:0.1.6-SNAPSHOT [S] | |
| [info] | +-org.typelevel:alleycats-tests_2.11:0.1.6-SNAPSHOT [S] | |
| [info] | |
benhutchison
/ AmmoniteReplSession
Last active
July 5, 2016 05:06
Eff: Can a Member type that takes a type parameter be expressed as a context bound of the effect type?
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| ~$> ./amm | |
| Loading... | |
| Welcome to the Ammonite Repl 0.6.2 | |
| (Scala 2.11.8 Java 1.8.0_51) | |
| @ load.plugin.ivy("org.spire-math" %% "kind-projector" % "0.8.0") | |
| @ load.ivy(("org.atnos" %% "eff-cats" % "1.7.4")) | |
| @ import cats.data._ | |
| import cats.data._ |
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