Ultimate ANTLR Reference - First program not working

I recently bought the Ultimate ANTLR Reference , and I am very pleased to start using ANTLR. The first chapter shows this grammar:

grammar T;

options {
    language = Java;
}

r : 'call' ID ';' {System.out.println("invoke " + $ID.text);} ;
ID : 'a'..'z'+ ;
WS : (' '|'\n'|'\r')+   {$channel=HIDDEN;} ;

I copied this grammar to a file, (extension .g), generated Lexer and Parser, and created the main class as follows:

import org.antlr.runtime.*;

public final class Test {
    public static void main(String[] args) throws Exception {
        ANTLRInputStream input = new ANTLRInputStream(System.in);
        TLexer lexer = new TLexer(input);
        CommonTokenStream tokens = new CommonTokenStream(lexer);
        TParser parser = new TParser(tokens);

        parser.r();
    }
}

There are no real errors, but when I run the main class and contribute:

call foo;

Nothing happens. "invoke foo" should be displayed, but nothing happens. I do not want to go to a book without doing a single exercise. I use ANTLR 3.4 in Eclipse if that matters. Sorry if this seems like a simple question, but I'm new to ANTLR.

Thanks,
Omer