Using JNA directly from the Scala REPL

gistfile1.txt

$ scala
Welcome to Scala version 2.8.1.final (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_24).
Type in expressions to have them evaluated.
Type :help for more information.

scala> :cp /usr/share/java/jna.jar                                                                                       
Added '/usr/share/java/jna.jar'.  Your new classpath is:
.:/usr/share/java/jna.jar

scala> import com.sun.jna._                                                                                              
import com.sun.jna._

scala> object HelloWorld { Native.register("m"); @native def sin(d: Double): Double }
defined module HelloWorld

scala> HelloWorld.sin(42)                                                                                                
res0: Double = -0.9165215479156338