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Version: ZIO 2.x

Introduction to ZIO CLI

Rapidly build powerful command-line applications powered by ZIO

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Installation​

To use ZIO CLI, we need to add the following to our build.sbt file:

libraryDependencies += "dev.zio" %% "zio-cli" % "0.5.0"

Example​

import zio.Console.printLine
import zio.cli.HelpDoc.Span.text
import zio.cli._

import java.nio.file.{Path => JPath}

object GitExample extends ZIOCliDefault {
  import java.nio.file.Path

  sealed trait Subcommand extends Product with Serializable
  object Subcommand {
    final case class Add(modified: Boolean, directory: JPath) extends Subcommand
    final case class Remote(verbose: Boolean)                 extends Subcommand
    object Remote {
      sealed trait RemoteSubcommand extends Subcommand
      final case class Add(name: String, url: String) extends RemoteSubcommand
      final case class Remove(name: String)           extends RemoteSubcommand
    }
  }

  val modifiedFlag: Options[Boolean] = Options.boolean("m")

  val addHelp: HelpDoc = HelpDoc.p("Add subcommand description")
  val add =
    Command("add", modifiedFlag, Args.directory("directory")).withHelp(addHelp).map { case (modified, directory) =>
      Subcommand.Add(modified, directory)
    }

  val verboseFlag: Options[Boolean] = Options.boolean("verbose").alias("v")
  val configPath: Options[Path]     = Options.directory("c", Exists.Yes)

  val remoteAdd = {
    val remoteAddHelp: HelpDoc = HelpDoc.p("Add remote subcommand description")
    Command("add", Options.text("name") ++ Options.text("url")).withHelp(remoteAddHelp).map { case (name, url) =>
      Subcommand.Remote.Add(name, url)
    }
  }

  val remoteRemove = {
    val remoteRemoveHelp: HelpDoc = HelpDoc.p("Remove remote subcommand description")
    Command("remove", Args.text("name")).withHelp(remoteRemoveHelp).map(Subcommand.Remote.Remove)
  }

  val remoteHelp: HelpDoc = HelpDoc.p("Remote subcommand description")
  val remote = {
    Command("remote", verboseFlag)
      .withHelp(remoteHelp)
      .map(Subcommand.Remote(_))
      .subcommands(remoteAdd, remoteRemove)
      .map(_._2)
  }

  val git: Command[Subcommand] =
    Command("git", Options.none, Args.none).subcommands(add, remote)

  val cliApp = CliApp.make(
    name = "Git Version Control",
    version = "0.9.2",
    summary = text("a client for the git dvcs protocol"),
    command = git
  ) {
    case Subcommand.Add(modified, directory) =>
      printLine(s"Executing `git add $directory` with modified flag set to $modified")
    case Subcommand.Remote.Add(name, url) =>
      printLine(s"Executing `git remote add $name $url`")
    case Subcommand.Remote.Remove(name) =>
      printLine(s"Executing `git remote remove $name`")
    case Subcommand.Remote(verbose) =>
      printLine(s"Executing `git remote` with verbose flag set to $verbose")

  }
}

object Example2 extends scala.App {
  println(GitExample.git.helpDoc.toPlaintext())
}

Output:

 COMMANDS

  - add [-m] <directory>      Add subcommand description
  - remote [(-v, --verbose)]  Remote subcommand description

References​