public void insertLastFocused(String symbol,boolean append){
  if (this.variable == lastFocused) {
    setVariable(symbol,append);
  }
 else {
    setExpression(symbol,append);
  }
}

public void insertLastFocused ( String symbol , boolean append ) { if ( this . variable == lastFocused ) { setVariable ( symbol , append ) ; } else { setExpression ( symbol , append ) ; } }
inserts the given symbol into the last focused field , of if there isn ' t one the expression field .
