private IExpression ParseOptions()
{
var enabled = GroupRegexOptions.None;
while (index != regex.Length && TryGetOption(out var option))
{
enabled |= option;
++index;
}
if (index == regex.Length || (regex[index] != '-' && regex[index] != ':' && regex[index] != ')'))
{
// The Regex constructor should prevent this
throw new InvalidOperationException();
}
var disabled = GroupRegexOptions.None;
if (regex[index] == '-')
{
++index;
while (index != regex.Length && TryGetOption(out var option))
{
disabled |= option;
++index;
}
if (index == regex.Length || (regex[index] != ':' && regex[index] != ')'))
{
// The Regex constructor should prevent this
throw new InvalidOperationException();
}
}
var currentOptions = options.Pop();
currentOptions |= enabled;
currentOptions &= ~disabled;
options.Push(currentOptions);
if (regex[index] == ':')
{
++index; // swallow ':'
var item = Parse();
return(OptionsGroup.Of(enabled, disabled, item));
}
else
{
return(InlineOptions.For(enabled, disabled));
}
}
/// <summary>
/// Creates a group that can enable or disable options for its subexpressions.
/// </summary>
/// <param name="enabled">The options to enable.</param>
/// <param name="disabled">The options to disable.</param>
/// <returns>The options group.</returns>
public static IOptionsGroup From(GroupRegexOptions enabled, GroupRegexOptions disabled, IEnumerable <IExpression> members)
{
if (members == null)
{
throw new ArgumentNullException(nameof(members));
}
ValidateRegexOptions(nameof(enabled), enabled);
ValidateRegexOptions(nameof(disabled), disabled);
var group = new OptionsGroup()
{
EnabledOptions = enabled, DisabledOptions = disabled
};
foreach (var member in members)
{
group.Add(member);
}
return(group);
}
