public static Result<IEnumerable<Token>, Error> ExplodeOptionList(
Result<IEnumerable<Token>, Error> tokenizerResult,
Func<string, Maybe<char>> optionSequenceWithSeparatorLookup)
{
var tokens = tokenizerResult.SucceededWith();
var replaces = tokens.Select((t,i) =>
optionSequenceWithSeparatorLookup(t.Text)
.Return(sep => Tuple.Create(i + 1, sep),
Tuple.Create(-1, '\0'))).SkipWhile(x => x.Item1 < 0);
var exploded = tokens.Select((t, i) =>
replaces.FirstOrDefault(x => x.Item1 == i).ToMaybe()
.Return(r => t.Text.Split(r.Item2).Select(Token.Value),
Enumerable.Empty<Token>().Concat(new[]{ t })));
var flattened = exploded.SelectMany(x => x);
return Result.Succeed(flattened, tokenizerResult.Messages());
}