how to set main class in SBT 0.13 project

Question

Could you guys please explain to me how to set main class in SBT project ? I'm trying to use version 0.13.

My directory structure is very simple (unlike SBT's documentation). In the root folder I have build.sbt with following content

name := "sbt_test"  version := "1.0"  scalaVersion := "2.10.1-local"  autoScalaLibrary := false  scalaHome := Some(file("/Program Files (x86)/scala/"))  mainClass := Some("Hi")  libraryDependencies ++= Seq(     "org.scalatest" % "scalatest_2.10" % "2.0.M5b" % "test" )  EclipseKeys.withSource := true 

And I have subfolder project with single file Hi.scala which contains following code

object Hi {   def main(args: Array[String]) = println("Hi!") } 

I'm able to compile it by calling sbt compile but sbt run returns

The system cannot find the file C:\work\externals\sbt\bin\sbtconfig.txt. [info] Loading project definition from C:\work\test_projects\sbt_test\project [info] Set current project to sbt_test (in build file:/C:/work/test_projects/sbt_test/) java.lang.RuntimeException: No main class detected.         at scala.sys.package$.error(package.scala:27) [trace] Stack trace suppressed: run last compile:run for the full output. [error] (compile:run) No main class detected. [error] Total time: 0 s, completed Apr 8, 2013 6:14:41 PM 

Answer 1

You need to put your application's source in src/main/scala/, project/ is for build definition code.

Answer 2

Try to use an object and extend it from App instead of using class

object Main extends App {   println("Hello from main scala object") }