scalaz-transfigure

A library for genericly composing/lifting operations in a stack of monadic contexts

Maven Dependency

<dependency>
  <groupId>com.github.m50d</groupId>
  <artifactId>scalaz-transfigure</artifactId>
  <version>0.8</version>
</dependency>

scalaz-transfigure is currently built against scala 2.11, scalaz 7.1 and shapeless 2.0.

Basic Usage

import scalaz.transfigure.TransfigureSyntax._
// fa could be an arbitrary stack of List/Option
val fa: List[Option[Int]] = List(Some(42))
// f returns some other arbitrary stack of List/Option
val f: Int ⇒ List[String] = x ⇒ List((x - 10).toString)
// transfigureTo returns exactly the requested stack
val g: List[Option[String]] = fa.transfigureTo[List, Option](f)

Flatmap API

import scalaz.transfigure.TransfigureSyntax._
val fa: String \/ Option[Int] = Some(42).right
val g: Int => Future[String \/ Float]
val h: Float => Future[Option[String]]

// b will be a Future[String \/ Option[_]]
// whatever arbitrary combinations of these are returned by g/h
val b = fa.mapWith[Future, ({type L[A]=String \/ A})#L, Option]
  .flatMap(g)
  .flatMap(h) //or
  .run        //.map(h)

Todo

• Add more UnapplyC implicits so that it's usable with more container types
• Make for/yield sugar work - I think this is probably impossible :(
• Add support for MonadTrans, or something more generic (e.g. a port of Haskell's Layer)