[Jmol-users] history - commands separation

[Paul P. <pau...@ac...>]

I have been working on a javascript function in order to cancel the last 
actions performed by the user (an undo function). I think it might 
interest some of the Jmol users :
- the new history command gives the succession of all the commands that 
have been sent to the applet.
- the consecutive sets of commands sent are separated by a | character.
- if 2 commands are separated by a semi-colon and are sent to the applet 
(eg: "select all; cpk on;") they appear in the history as a single 
command (eg: "previous command; | select all; cpk on; | next command...").

To make an undo function I choose to split the history based on the | 
character, and to concat the different pieces except the last one. The 
new script preceded by a command which reset the interface is then sent 
to the applet and it works great.
The problem begins when you want to perform a second undo command : as 
all the previous commands are sent as one set, they are no longer 
separated by a | in the history and they appear as a single command.

I found a workaround (there might be some others) by inserting a #|; 
between the commands from the history in order to keep a separation 
between these consecutives commands.
In my opinion, the easyest way would be that the | character is 
understood by Jmol as a separator for the history, then one would only 
have to send a substring of the history in order to perform an undo, and 
it could be used recursively. I don't know if it could be easily 
implemented but I think it should help a lot.

By the way, if some are interested by the javascript I used, here it is :
function undo() {
  answer = jmolScriptWaitAsArray('show history; history on;');
  script = answer[0][0][3];
 
  pieces = script.split(' #|;');
  fin = pieces[pieces.length-1].split('|');
  debut = pieces.slice(0,-1);
  script = debut.concat(fin);
 
  while (script[script.length-1]==' ') {
    script.length--;
  }
  spt='';
 
  for (i=0;i<script.length-1;i++) {
    if(script[i]!='')
      spt += script[i]+' #|;' ;
  }
  if (script[0].indexOf(initscript)==-1) {
    spt = initscript + ' #|;' + spt;
  }
  //alert(spt);
  executer(spt);
}

Paul