Scala, ZIO - how to return value from Task?-CodePudding

I have a simple for-comprehension code:

def nameFormatter(request: SomeRequest) : FormattedData = {
      for {
        config <- ZIO.fromOption(configuration.get(request.name)).orElseFail( new Exception("Unknown config"))
        name = config.data.name.pipe(SomeName)
      } yield FormattedData(
        name,
        request.age
      )
    }

But this method returns:

ZIO[Any, Exception, FormattedData]

I would like to change this method to return only FormattedData, not the whole ZIO. Is it possible? Or maybe I should somehow read returned type and get value from it?

CodePudding user response：

ZIO makes it difficult to do this because it is unsafe and it defeats the purpose of using ZIO. You can tell from the type ZIO[Any, Exception, FormattedData] that it can fail with an Exception if you try to materialise the value.

If you really want to do it:

zio.Runtime.default.unsafeRun(nameFormatter(request))

otherwise you should be composing the rest of your code with the result of nameFormatter(request) and run it with something like:

import zio.{ExitCode, URIO, ZIO}

object Main extends zio.App {
  override def run(args: List[String]): URIO[zio.ZEnv, ExitCode] =
    (for {
      formattedData <- nameFormatter(request)
      // rest of your code
    } yield ()).exitCode
}

CodePudding user response：

The way to use it is

nameFormatter(request).flatMap { formattedData =>
  // whatever you want to do with the returned value
  // ...
  // the rest of your program
}

or in a for comprehension:

for {
  formattedData <- nameFormatter(request)
  // rest of your program
} yield ()

This DOES NOT answer your question, however it's probably what you wanted to do.