Main.java 文件源码

public static int run(final String data) {
    // Create a CharStream that reads from standard input.
    final CharStream input = CharStreams.fromString(data);

    // Create a lexer that feeds off of input CharStream.
    final ExprSimpleLexer lexer = new ExprSimpleLexer(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 ExprSimpleParser parser = new ExprSimpleParser(tokens);

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

    // Create a generic parse tree walker that can trigger callbacks.
    final ParseTreeWalker walker = new ParseTreeWalker();

    // Walk the tree created during the parse, trigger callbacks.
    final ExprListener listener = new ExprListener();
    walker.walk(listener, tree);
    return listener.getResult();
}