title: What's the purpose of Function.const?
body: <p>It is in <a href="http://www.scala-lang.org/archives/downloads/distrib/files/nightly/docs/library/index.html#scala.Function$" rel="noreferrer">ScalaDoc</a> but without much documentation. It seems that it always returns the first parameter.</p>
  
  <p><code>Function.const(1)(2)</code> for instance returns <code>1</code>.</p>
  
  <p>Why does it exist and why is it useful?</p>