title: Gnuplot read line style from data file column
body: <p>I'd like to draw an impulse graph from a text file that looks like this:</p>
  
  <pre><code>II 5 0 0 288.40 1.3033e+14 
  II 6 0 0 289.60 1.5621e+14 
  II 1 4 0 302.70 3.0084e+13 
  II 2 4 0 303.40 4.0230e+13 
  II 1 5 1 304.40 3.4089e+13
  </code></pre>
  
  <p>The plot conceptually should be <code>plot "datafile.dat" using 5:6 w impulses ls $2</code>.</p>
  
  <p>Basically, given a previously defined set of line styles, I'd like to input the line style number from column 2 for every couple of plotted points from column 5 and 6.<br>
  Also I'd like to create a text box, for every plotted point, taking strings from the first four columns.</p>
  
  <p>Does somebody know if that's possible?</p>