title: SML Ml Programing Function is_older date with boolean conditon
body: <p>I am newbie in ML programming, I have a homework to write a function is_older that takes two dates and evaluates to true or false. It evaluates to true if the first argument is a date that comes before the second argument.<br>
  (If the two dates are the same,
  the result is false.)</p>
  
  <pre><code>val is_older = fn : (int * int * int) * (int * int * int) -&gt; bool // Binding Like
  </code></pre>
  
  <p>I tried this (using SML of New Jersy cmd prompt) </p>
  
  <pre><code>fun is_older((y1,m1,d1),(y2,m2,d2))= if (y1&lt;y2) then true 
  else if (y1=y2 andalso m1&lt;m2) then true 
  else if (y1=y2 andalso m1=m2 andalso d1&lt;d2) then true;
  </code></pre>
  
  <p>Its gives error </p>
  
  <pre><code>Error syntax error: deleting SEMICOLON ID 
  </code></pre>