How to access the following[] tokens from state?

[talek]

Hi,

Within a parser, Is it possible to know what are the available paths to follow from the current position? For example, I have the following very simple grammar:

grammar Simple;

options {
  language=Ruby;
  k='*';
  backtrack=true;
  memoize=true;
  output=AST;
}

simple
  :   
  SELECT { p @state } (ALL | FROM) 'DUAL'
  ;

SELECT: 'SELECT';
ALL: 'ALL';
FROM: 'FROM';

Then I use the following snippet:

require 'rubygems'
require 'antlr3'
require 'SimpleParser.rb'
require 'SimpleLexer.rb'

text = 'SELECT'
lexer = Simple::Lexer.new(text)
tokens = ANTLR3::CommonTokenStream.new(lexer)
parser = Simple::Parser.new(tokens)
parser.simple

Runing this I was hoping to get the following[] property of the @state with all the next possible paths to follow. Unfortunately, this property is always empty. Can you shed some light here? How this property is supposed to work?

Many thanks!

[talek]

Meanwhile, I figured out how this array is filled in by looking into the code.