public void toASCIIFile(File file) {
   try {
     ASCIIFile.write(file, PArray.cat(M));
   } catch (NullPointerException e) {
     // System.out.println("File not saved");
   }
 }
 public void toClipBoard() {
   try {
     Toolkit.getDefaultToolkit()
         .getSystemClipboard()
         .setContents(new StringSelection(PArray.cat(M)), null);
   } catch (IllegalStateException e) {
     JOptionPane.showConfirmDialog(
         null,
         "Copy to clipboard failed : " + e.getMessage(),
         "Error",
         JOptionPane.DEFAULT_OPTION,
         JOptionPane.ERROR_MESSAGE);
   }
 }