protected static void parseVariable(PsiBuilder builder, IElementType elementType) {
    final PsiBuilder.Marker marker = builder.mark();
    builder.advanceLexer();
    if (builder.getTokenType() == XPathTokenTypes.VARIABLE_PREFIX) {
      builder.advanceLexer();
      checkMatches(builder, XPathTokenTypes.COL, XPathBundle.message("parsing.error.colon.expected"));
    }
    checkMatches(builder, XPathTokenTypes.VARIABLE_NAME, XPathBundle.message("parsing.error.variable.expected"));
    marker.done(elementType);
  }
protected static void parseVariable(PsiBuilder builder, IElementType elementType)