MainVisitor.java 文件源码

public static int run(final String data) throws IOException {
    CharStream input;
    if (data == null) {
        // Create a CharStream that reads from standard input.
        input = CharStreams.fromStream(System.in);
    } else {
        input = CharStreams.fromString(data);
    }

    // Create a lexer that feeds off of input CharStream.
    final ExprAdvancedLexer lexer = new ExprAdvancedLexer(input);

    // Create a buffer of tokens pulled from the lexer.
    final CommonTokenStream tokens = new CommonTokenStream(lexer);

    // Create a parser that feeds off the tokens buffer.
    final ExprAdvancedParser parser = new ExprAdvancedParser(tokens);

    // Begin parsing at "prog" rule.
    final ParseTree tree = parser.prog();

    final ExprVisitor eval = new ExprVisitor();
    eval.visit(tree);
    return eval.getResult();
}