/// <summary>
/// Appends the text representation of the content of the current instance to the specified <see cref="PatternBuilder"/>.
/// </summary>
/// <param name="builder">The builder to use for appending the text.</param>
/// <exception cref="ArgumentNullException"><paramref name="builder"/> is <c>null</c>.</exception>
public void AppendBaseGroupTo(PatternBuilder builder)
{
if (builder == null)
{
throw new ArgumentNullException(nameof(builder));
}
if (Negative)
{
builder.AppendDirect('^');
}
AppendContentTo(builder);
}