String text = doc.getText(start, length);
//fixme
final String replaced = text.replaceAll("(\\$?[a-zA-Z0-9_]+ *=)(\\>)", "$1");
final BaseDocument bdoc = (BaseDocument) doc;
bdoc.runAtomic(new Runnable() {
@Override
public void run() {
try {
bdoc.remove(start, length);
bdoc.insertString(start, replaced, null);