#Monoid in Scala by programmers from different backgrounds#
In spirit of The Evolution of a Haskell Programmer. Originally stolen from isoresursive.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| > effect/console | |
| [warn] Credentials file /home/folone/.ivy2/.credentials does not exist | |
| [warn] Credentials file /home/folone/.ivy2/.credentials does not exist | |
| [info] Starting scala interpreter... | |
| [info] | |
| Welcome to Scala version 2.9.2 (OpenJDK 64-Bit Server VM, Java 1.7.0_21). | |
| Type in expressions to have them evaluated. | |
| Type :help for more information. | |
| scala> import scalaz._, Scalaz._, effect._ |
folone
/ gist:5320098
Last active
December 15, 2015 20:40
Fooling around with State, defined as a monad of Adjunction[Writer, Reader], as per http://stackoverflow.com/a/4702513/163423
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| > core/console | |
| [warn] Credentials file /home/folone/.ivy2/.credentials does not exist | |
| [info] Starting scala interpreter... | |
| [info] | |
| Welcome to Scala version 2.9.2 (OpenJDK 64-Bit Server VM, Java 1.7.0_17). | |
| Type in expressions to have them evaluated. | |
| Type :help for more information. | |
| scala> import scalaz._ | |
| import scalaz._ |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| BUILD SUCCESSFUL | |
| Total time: 9 minutes 21 seconds | |
| Welcome to Scala version 2.11.0-20130329-204437-40d2981c24 (OpenJDK 64-Bit Server VM, Java 1.7.0_17). | |
| Type in expressions to have them evaluated. | |
| Type :help for more information. | |
| scala> :kind scala.Option | |
| Option's kind is * -> * | |
| scala> :k scalaz.Unapply |
folone
/ kind.scala
Last active
February 20, 2018 22:18
— forked from eed3si9n/kind.scala
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| // Updated for Scala 2.10.0. | |
| def kind[A: scala.reflect.runtime.universe.TypeTag](a: A): String = { | |
| import scala.reflect.runtime.universe._ | |
| def typeKind(sig: Type): String = sig match { | |
| case PolyType(params, resultType) => | |
| (params map { p => | |
| typeKind(p.typeSignature) match { | |
| case "*" => "*" | |
| case s => "(" + s + ")" | |
| } |
folone
/ isomonoid.scala
Last active
December 15, 2015 07:39
Monoid instance throught an isomorphism
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| scala> import scalaz._ | |
| import scalaz._ | |
| scala> import std.option.optionFirst | |
| import std.option.optionFirst | |
| scala> import syntax.monoid._ | |
| import syntax.monoid._ | |
| scala> import Isomorphism._ |
folone
/ adjunction.scala
Last active
December 15, 2015 07:18
- Things, that can be described as Adjunctions
- Things, that can be described as Cofree
- Things, that can be described as Free monads, inspired by http://yow.eventer.com/yow-2012-1012/lambda-the-ultimate-dependency-injection-framework-by-runar-bjarnason-1277
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| type State[E] = Adjunction[({type λ[α] = Writer[E, α]})#λ, ({type λ[α] = Reader[E, α]})#λ] | |
| type Store[E] = Adjunction[({type λ[α] = Reader[E, α]})#λ, ({type λ[α] = Writer[E, α]})#λ] | |
| type Cont = Adjunction[Function0, Function0] // Function0 -| Function0 |
folone
/ gist:4946543
Last active
December 13, 2015 17:18
Hanoi towers at compile time become very easy with dependent types.
https://gist.github.com/travisbrown/3772462
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| > shapeless-core/console | |
| [warn] Credentials file /home/folone/.ivy2/.credentials does not exist | |
| [info] Compiling 24 Scala sources to /home/folone/workspace/shapeless/core/target/scala-2.11/classes... | |
| [info] Starting scala interpreter... | |
| [info] | |
| Welcome to Scala version 2.11.0-20130205-141957-132e09fc2e (OpenJDK 64-Bit Server VM, Java 1.7.0_09). | |
| Type in expressions to have them evaluated. | |
| Type :help for more information. | |
| scala> import shapeless.SingletonTypes._ |
folone
/ gist:4945168
Last active
April 27, 2017 13:10
A taste of dependent types in scala with shapeless.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| > shapeless-core/console | |
| [warn] Credentials file /home/folone/.ivy2/.credentials does not exist | |
| [info] Compiling 24 Scala sources to /home/folone/workspace/shapeless/core/target/scala-2.11/classes... | |
| [info] Starting scala interpreter... | |
| [info] | |
| Welcome to Scala version 2.11.0-20130205-141957-132e09fc2e (OpenJDK 64-Bit Server VM, Java 1.7.0_09). | |
| Type in expressions to have them evaluated. | |
| Type :help for more information. | |
| scala> import shapeless._ |
folone
/ gist:4729451
Last active
December 12, 2015 06:28
Dependent types in scala.
https://github.com/milessabin/shapeless/blob/topic/macro-paradise/core/src/main/scala/shapeless/snat.scala
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| shapeless [0849b6f...] % sbt | |
| [info] Loading project definition from /home/folone/workspace/shapeless/project | |
| [info] Set current project to shapeless (in build file:/home/folone/workspace/shapeless/) | |
| > shapeless-core/console | |
| [warn] Credentials file /home/folone/.ivy2/.credentials does not exist | |
| [info] Compiling 2 Scala sources to /home/folone/workspace/shapeless/core/target/scala-2.11/classes... | |
| [info] Compiling 24 Scala sources to /home/folone/workspace/shapeless/core/target/scala-2.11/classes... | |
| [info] Starting scala interpreter... | |
| [info] | |
| Welcome to Scala version 2.11.0-20130205-141957-132e09fc2e (OpenJDK 64-Bit Server VM, Java 1.7.0_09). |