code: private List<String> resolveVariable(String filter, String text) {
      List<String> ret = new ArrayList<>();
      Matcher m = PATTERN.matcher(text);
      while (m.find()) {
        ParsedStatement statement = ParsedStatement.fromMatcher(m);
        if (statement != null && statement.getVariable().startsWith(filter)) {
          ret.add(statement.getVariable());
        }
      }
      return ret;
    }
docs: this method returns the variables defined by the filter. e.g. data-sly-use.variable
  
  @param filter
  @param text
  @return the variable defined by the filter