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object Hello { def main(args: Array[String]): Unit = {
println("Hello world.")
}
}
powerbookg4:tmp zemian$ scalac Hello.scala powerbookg4:tmp zemian$ scala Hello
Hello world.
Note that Scala main entry program is a "object" instead of "class". "object" in Scala is like a class that define a type, but it force it to be a singleton(only one instance), so it almost like "static" in Java. Your main entry in command line must be an object with the main method defined.
You may turn your source file into a script by enter a expression that invoke the main method on the end of the file, and then run it through "scala" instead of compiling it. For example:
object Hello { def main(args: Array[String]): Unit = {
println("Hello world.")
}
}
Hello.main(args)
powerbookg4:tmp zemian$ scala Hello.scala Hello world.
Note the difference. 1 no compile. 2 you give scala the script file name, not the type name!
Happy programming!
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Created by Michael Levin Dec 18, 2008 at 6:56pm. Last updated by Michael Levin May 4, 2018.
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