title: How to use / refer to the negation of a boolean function in Scala?
body: <p>I'm trying to use the negation of a boolean function in Scala, such as:</p>
  
  <pre><code>def someFunction(x: Set, p: Int =&gt; Boolean): Boolean = 
      someOtherFunction(x, !p)
  </code></pre>
  
  <p>But I get the error:</p>
  
  <pre><code> value unary_! is not a member of Int =&gt; Boolean
  </code></pre>
  
  <p>How can I refer to the negation of p? </p>