stm4cats

KO | EN

gitlite — search

#javascript #python #hacktoberfest #react #ai #typescript #llm #go #golang #android #machine-learning #rust #deep-learning #linux

(★ 36)

STM monad for cats-effect

stm4cats 최신버젼 다운로드

최종 버전 다운로드 (.zip)

// repository documentation

Was this content helpful?

★ 0 (0 ratings)

# stm4cats
![Maven Central](https://img.shields.io/maven-central/v/com.olegpy/stm4cats_2.12.svg?color=06C)
[![Build Status](https://travis-ci.org/oleg-py/stm4cats.svg?branch=master)](https://travis-ci.org/oleg-py/stm4cats)
[![Coverage Status](https://coveralls.io/repos/github/oleg-py/stm4cats/badge.svg?branch=master)](https://coveralls.io/github/oleg-py/stm4cats?branch=master)

An implementation of STM for any cats-effect compatible effect type.

Current stable version is `0.1.0-M1`, available for Scala 2.11 and 2.12 and Scala.JS 0.6:
```scala
// Use %%% for Scala.JS
libraryDependencies += "com.olegpy" %% "stm4cats" % "0.1.0-M1"
```

Or, if you're feeling adventurous, a snapshot is build from `master` on each commit.
```scala
resolvers += Resolver.sonatypeRepo("snapshots")
libraryDependencies += "com.olegpy" %% "stm4cats" % "0.1.0-SNAPSHOT"
```

### Try it
```scala
import cats.implicits._
import cats.effect.IO
import com.olegpy.stm._
import scala.concurrent.ExecutionContext.global
import scala.concurrent.duration._

implicit val cs = IO.contextShift(global)
implicit val timer = IO.timer(global)

def transfer(fromR: TRef[Int], toR: TRef[Int], amt: Int): STM[Unit] =
  for {
    from <- fromR.get
    if from >= amt // Or STM.check(from >= amt)
    _ <- fromR.update(_ - amt)
    _ <- toR.update(_ + amt)
  } yield ()
  
def freeMoney(toR: TRef[Int]): IO[Unit] = STM.atomically[IO] {
  toR.update(_ + 10)
}

val io = for {
  fromR <- TRef(0).commit[IO]
  // Or shorter syntax:
  toR   <- TRef.in[IO](0)
  amt   =  100

f1    <- transfer(fromR, toR, amt).commit[IO].start
  f2    <- (freeMoney(fromR) >> IO.sleep(1.second)).foreverM.start
  // In 10 seconds, the transfer succeeds
  _     <- f1.join
  _     <- f2.cancel
  res   <- toR.get.commit[IO]
  _     <- IO(assert(res == amt))
} yield ()

io.unsafeRunSync() // Well, not on JS
```

### Acknowledgements 
My interest in STM, as well as some of API in stm4cats was influenced by:
- [Talk](https://www.youtube.com/watch?v=d6WWmia0BPM) by @jdegoes and @wi101 on STM in ZIO
- An [alternative implementation](https://github.com/TimWSpence/cats-stm) by @TimWSpence
- And last, but not least,
[Beautiful concurrency paper](https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/beautiful.pdf)
by Simon Peyton Jones

stm4cats

stm4cats 최신버젼 다운로드

오늘의 추천 프로젝트

Was this content helpful?

Recent Feedback

stm4cats

stm4cats 최신버젼 다운로드

오늘의 추천 프로젝트

Was this content helpful?

Recent Feedback

Download README