EBNF Sample code on homepage doesn't parse as expected (returns error)

[DanTup]

The sample code on the homepage doesn't appear to work as expected:

// Copied from https://github.com/picoe/Eto.Parse
var grammar = new EbnfGrammar().Build(@"
(* := is an extension to define a literal with no whitespace between repeats and sequences *)
ws := {? Terminals.WhiteSpace ?};

letter or digit := ? Terminals.LetterOrDigit ?;

simple value := letter or digit, {letter or digit};

bracket value = simple value, {simple value};

optional bracket = '(', bracket value, ')' | simple value;

first = optional bracket;

second = optional bracket;

grammar = ws, first, second, ws;
", "grammar");

var input = "  hello ( parsing world )  ";
var match = grammar.Match(input);

var firstValue = match["first"]["value"].Value;
var secondValue = match["second"]["value"].Value;

Console.WriteLine("F: {0}", firstValue);
Console.WriteLine("S: {0}", secondValue);
Console.WriteLine(match.ErrorMessage);

When run, this outputs:

F:
S:
Index=24, Context="ing world >>>)  "
ChildIndex=27, Context=" world )  >>>"
Expected:
letter or digit: Char: Letter or Digit
simple value: Sequence

[cwensley]

There is an outstanding issue where the errors will be populated even when successful. You should check the match.Success property first before looking at the Errors or ErrorMessage properties.

[cwensley]

Closing as this is really old and I believe it was answered.