Scala 'using' implementation

gistfile1.scala

object UsingDemo {
	
	def main( args : Array[String] ) {
		
		using( new A() ) { a =>
			a.print("Hello World " )
		}
	}
	
	
	
	def using[A, B <: {def close(): Unit}] ( closeable:B ) ( f: B => A ) : A = {
		try {
			f(closeable)
		}
		finally {
			closeable.close()
		}
	} 
	

	class A {
		
		def print(s:String) = {
			println( s )
		}
		
		def close() = {
			println( "closing" )
		}
	}
}