private void showDocumentation(final Function<String, String> docHelper) {
final String buffer = in.getCursorBuffer().buffer.toString();
final int cursor = in.getCursorBuffer().cursor;
final String doc = docHelper.apply(buffer.substring(0, cursor));
try {
if (doc != null) {
in.println();
in.println(doc);
in.redrawLine();
in.flush();
} else {
in.beep();
}
} catch (IOException ex) {
throw new IllegalStateException(ex);
}
}
