Pros of Scala

• Scala is the official programming language for the Scala compiler and the Scala standard library, providing a comprehensive and well-maintained ecosystem.
• The Scala repository has a larger community and more active development compared to sbt, with more contributors and a wider range of features and functionality.
• The Scala codebase is generally considered to be of higher quality, with more thorough testing and a more rigorous development process.

Cons of Scala

• The Scala repository is larger and more complex than sbt, which can make it more challenging for new contributors to get started.
• The Scala codebase is written in a more advanced and functional programming-oriented style, which may be less accessible to developers with a background in more imperative languages.
• The Scala repository has a more formal and bureaucratic development process, which can sometimes slow down the pace of development and innovation.

Code Comparison

Scala:

def foldLeft[B](z: B)(op: (B, A) => B): B = {
  var result = z
  val it = iterator
  while (it.hasNext) {
    result = op(result, it.next)
  }
  result
}

sbt:

def apply(state: State): State = {
  val extracted = Project.extract(state)
  val (newState, value) = extracted.runTask(Keys.compile, state)
  newState
}

Pros of Cats

• Cats is a functional programming library that provides a set of abstractions for working with data types in a more declarative and composable way.
• The library has a strong focus on type-safety and provides a rich set of type classes and data structures that can be used to build robust and maintainable applications.
• Cats has a large and active community, with a wide range of contributors and a well-documented ecosystem of related libraries.

Cons of Cats

• Cats can have a steeper learning curve compared to sbt, especially for developers who are new to functional programming.
• The library can be more verbose and require more boilerplate code than some other Scala libraries, which can make it less suitable for small or simple projects.
• Cats has a larger dependency footprint than sbt, which can impact the overall size and complexity of a project.

Code Comparison

sbt:

val scalaVersion = "2.13.8"

lazy val root = (project in file("."))
  .settings(
    name := "my-project",
    version := "0.1.0-SNAPSHOT",
    scalaVersion := scalaVersion,
    libraryDependencies += "org.scala-lang.modules" %% "scala-xml" % "2.1.0"
  )

Cats:

import cats.Monad
import cats.implicits._

def program[F[_]: Monad](x: Int, y: Int): F[Int] = {
  for {
    a <- Monad[F].pure(x)
    b <- Monad[F].pure(y)
  } yield a + b
}

Pros of scala/scala3

• Scala 3 introduces a more concise and expressive syntax, making the language more approachable for new developers.
• The new type system in Scala 3 provides better type inference and type checking, improving overall code quality.
• Scala 3 has a stronger focus on functional programming, with features like given instances and extension methods.

Cons of scala/scala3

• Scala 3 is a significant departure from Scala 2, which may require more effort for existing Scala 2 developers to migrate.
• The adoption of Scala 3 may be slower compared to Scala 2, as the ecosystem and tooling catch up to the new version.
• Some legacy libraries and frameworks may not be immediately compatible with Scala 3, requiring additional effort to update.

Code Comparison

sbt/sbt:

lazy val root = (project in file("."))
  .settings(
    name := "sbt",
    description := "sbt, the interactive build tool",
    organization := "org.scala-sbt",
    version := "1.8.2",
    scalaVersion := "2.12.17",
    // ...
  )

scala/scala3:

object Main:
  def main(args: Array[String]): Unit =
    println("Hello, Scala 3!")

Pros of scala-native/scala-native

• Native Compilation: scala-native compiles Scala code directly to native machine code, allowing for faster execution and better performance compared to the JVM-based approach of sbt/sbt.
• Lower Memory Footprint: The native compilation of scala-native results in a smaller memory footprint for the compiled applications, making it suitable for resource-constrained environments.
• Interoperability with C: scala-native provides seamless interoperability with C libraries, enabling developers to leverage existing C code and integrate it into their Scala projects.

Cons of scala-native/scala-native

• Limited Ecosystem: The scala-native ecosystem is relatively smaller compared to the extensive ecosystem of sbt/sbt, which has a larger community and a wider range of available libraries and tools.
• Complexity: The native compilation process and the integration with C libraries in scala-native can be more complex and require more specialized knowledge compared to the simpler JVM-based approach of sbt/sbt.
• Portability: While scala-native aims to be cross-platform, the native compilation process may introduce platform-specific challenges, making it less portable than the JVM-based sbt/sbt.

Code Comparison

Here's a brief code comparison between sbt/sbt and scala-native/scala-native:

sbt/sbt (build.sbt):

name := "My Project"
version := "1.0"
scalaVersion := "2.13.8"

libraryDependencies ++= Seq(
  "org.scala-lang.modules" %% "scala-xml" % "2.1.0",
  "org.scalatest" %% "scalatest" % "3.2.12" % "test"
)

scala-native/scala-native (build.sbt):

enablePlugins(ScalaNativePlugin)

nativeConfig ~= {
  _.withLinkingOptions("-lm")
   .withGC("boehm")
   .withMode("debug")
}

libraryDependencies ++= Seq(
  "org.scala-native" %%% "stdlib-nativelib" % "0.4.7",
  "org.scalatest" %%% "scalatest" % "3.2.12" % "test"
)

Pros of Scala.js

• Scala.js allows developers to write client-side web applications in Scala, which can be beneficial for teams already familiar with the Scala language.
• Scala.js provides a type-safe and functional approach to web development, which can lead to more robust and maintainable code.
• Scala.js can leverage the vast ecosystem of Scala libraries, enabling developers to reuse existing code and tools.

Cons of Scala.js

• Scala.js has a steeper learning curve compared to more widely-used web development technologies like JavaScript, React, or Angular.
• The Scala.js ecosystem may not be as mature and well-supported as the JavaScript ecosystem, which can make it more challenging to find solutions to common web development problems.
• Deploying Scala.js applications may require additional configuration and setup compared to traditional JavaScript-based web applications.

Code Comparison

sbt/sbt

lazy val root = (project in file("."))
  .settings(
    name := "My Project",
    version := "0.1.0-SNAPSHOT",
    scalaVersion := "2.12.8",
    libraryDependencies += "org.scalatest" %% "scalatest" % "3.0.5" % "test"
  )

scala-js/scala-js

import org.scalajs.dom
import scala.scalajs.js.annotation.JSExportTopLevel

@JSExportTopLevel("main")
def main(): Unit = {
  val h1 = dom.document.createElement("h1")
  h1.textContent = "Hello, Scala.js!"
  dom.document.body.appendChild(h1)
}

Pros of scalaz/scalaz

• Scalaz provides a rich set of functional programming utilities and abstractions, which can be highly useful for building complex, type-safe applications.
• The library has a strong focus on purity and immutability, which can lead to more reliable and maintainable code.
• Scalaz has a large and active community, with a wealth of resources and documentation available.

Cons of scalaz/scalaz

• The learning curve for Scalaz can be steep, especially for developers new to functional programming concepts.
• The library can be opinionated and may not align with the preferences of all Scala developers.
• Scalaz can sometimes be perceived as overly complex or "academic", which may make it less approachable for some users.

Code Comparison

sbt/sbt

lazy val root = (project in file("."))
  .settings(
    name := "sbt",
    description := "sbt, the interactive build tool",
    organization := "org.scala-sbt",
    version := "1.8.2",
    scalaVersion := "2.12.17",
    // ...
  )

scalaz/scalaz

import scalaz._
import Scalaz._

val myList: List[Int] = List(1, 2, 3, 4, 5)
val doubled: List[Int] = myList.map(_ * 2)
val summed: Int = myList.foldLeft(0)(_ + _)