public static void load(InputStream in, Proto proto) throws Exception
    {
        // Create an input character stream from standard in
        ANTLRInputStream input = new ANTLRInputStream(in);
        // Create an ExprLexer that feeds from that stream
        ProtoLexer lexer = new ProtoLexer(input);
        // Create a stream of tokens fed by the lexer
        CommonTokenStream tokens = new CommonTokenStream(lexer);
        // Create a parser that feeds off the token stream
        ProtoParser parser = new ProtoParser(tokens);
        // Begin parsing at rule prog
        parser.parse(proto);
    }
Creates the error/warning message that we need to show users/IDEs when ANTLR has found a parsing error, has
recovered from it and is now telling us that a parsing exception occurred.

@param tokenNames
           token names as known by ANTLR (which we ignore)
@param e
           The exception that was thrown
protostuff-parser/src/main/java/io/protostuff/parser/AbstractParser.java