Exception handling uses the familiar try / catch, try / catch / finally and try / finally constructions. Their semantics are the same as found in other languages such as Java, especially regarding the handling of finally blocks.

The following snippets show each exception handling form.

# Good old try / catch
try {
  something()
} catch (e) {
  e: printStackTrace()
}

# A try / finally
try {
  doSomething()
} finally {
  cleanup()
}

# Full try / catch / finally construct
try {
  doSomething()
} catch (e) {
  e: printStackTrace()
  case {
    when e oftype IOException.class {
      println("Oh, an I/O exception that I was expecting!")
    }
    when e oftype SecurityException.class {
      println("Damn, I didn't expect a security problem...")
      throw e
    }
    otherwise {
      throw e
    }
  }
} finally {
  cleanup()
}