title: How yacc knows for look ahead
body: <p>How could yacc knows to shift <code>*</code> but not to reduce <code>T to E</code> in line 10</p>
  
  <pre><code>STACK       INPUT BUFFER    ACTION
  $           num1+num2*num3$ shift
  $num1       +num2*num3$     reduc
  $F          +num2*num3$     reduc
  $T          +num2*num3$     reduc
  $E          +num2*num3$     shift
  $E+     num2*num3$          shift
  $E+num2 *num3$              reduc
  $E+F        *num3$              reduc
  $E+T        *num3$              shift      /////****//
  E+T*        num3$              shift       /////****//
  E+T*num3    $                  reduc
  E+T*F       $                  reduc
  E+T         $                  reduc
  E           $                  accept
  </code></pre>
  
  <p>Does it automatically design table?</p>