title: Infinite main loop in F#
body: <p>A usual pattern for CLI application is to run in infinite loop, until user types some quit command. Like, in C language:</p>
  
  <pre><code>while(1){
  scanf("%c", &amp;op);
      ...
      else if(op == "q")
          break;
      }
  </code></pre>
  
  <p>What would be the pattern for such console application in F# (tried to use tail recursrion, but failed)?</p>