title: Creating a "Next Run Time" date from a cronjob-like syntax
body: <p>In an app I'm creating a user is given the possibility to schedule a repeating task. Simply the values for generating the interval schema are:</p>
  
  <pre><code>Minute: [0-59, 90 (each minute)]
  Hour: [0-23, 90 (each hour)]
  Day of month: [1-31, 90 (each day of month), 91 (last day of month)]
  Month: [1-12, 90 (each month)]
  </code></pre>
  
  <p>So, for example I've got this format: 10 - 2 - 90 - 90 which translates to <code>2015-07-16 2:10</code>. The method determining the next run time date is able to present me this date. But, I'm looking for the efficient way to check if the next run time date has already passed (easy part) but then generate the first next run time date again. In this case it would be <code>2015-07-17 2:10</code>. </p>
  
  <p>I've found out that our brain is easily up to the task but I'm unsure which logical steps to follow to determine this in the most efficient way (without writing out all posibilities that is).</p>
  
  <p>Any suggestions? </p>