/// <summary>
            /// Parses a <see cref="Match"/> into a <see cref="DateToken"/>.
            /// </summary>
            /// <param name="match">A <see cref="Match"/> representation of a <see cref="DateToken"/>.</param>
            /// <param name="provider">An <see cref="IFormatProvider"/>.</param>
            /// <returns>The <see cref="DateToken"/> parsed from the <see cref="Match"/>.</returns>
            /// <exception cref="ArgumentNullException">If <paramref name="match"/> or <paramref name="provider"/> is
            /// <c>null</c>.</exception>
            /// <exception cref="FormatException">If the <paramref name="match"/> is not a supported representation of
            /// a <see cref="DateToken"/>.</exception>
            protected override DateToken ParseInternal(Match match, IFormatProvider provider)
            {
                SpecialDateDefinition specialDateDefinition = GetSpecialDateDefinitionForMatch(match);

                if (specialDateDefinition == null)
                {
                    throw new FormatException();
                }

                return(new SpecialDateToken {
                    SpecialDate = specialDateDefinition.SpecialDate
                });
            }
        /// <summary>
        /// Returns a string that represents the current object.
        /// </summary>
        /// <param name="provider">An <see cref="IFormatProvider"/> to use.</param>
        /// <returns>A string that represents the current object.</returns>
        public override string ToString(IFormatProvider provider)
        {
            try
            {
                this.ThrowIfNotValid();

                SpecialDateDefinition specialDateDefinition = this.GetSpecialDateDefinition();
                return(specialDateDefinition.GetName(provider));
            }
            catch
            {
                return(this.GetType().ToString());
            }
        }
        /// <summary>
        /// Returns the next date after <paramref name="minDate"/> that is represented by this token.
        /// </summary>
        /// <remarks>
        /// This method may return a date that is before <paramref name="minDate"/> if there is no date after <paramref
        /// name="minDate"/> that is represented by this token.
        /// </remarks>
        /// <param name="minDate">The minimum date to return. The time part is ignored.</param>
        /// <param name="inclusive">A value indicating whether the returned date should be on or after rather than
        /// strictly after <paramref name="minDate"/>.</param>
        /// <returns>The next date after <paramref name="minDate"/> that is represented by this token.</returns>
        /// <exception cref="InvalidOperationException">If this token is not valid.</exception>
        public override DateTime ToDateTime(DateTime minDate, bool inclusive)
        {
            this.ThrowIfNotValid();

            SpecialDateDefinition specialDateDefinition = this.GetSpecialDateDefinition();

            DateTime date = new DateTime(
                minDate.Year,
                specialDateDefinition.Month,
                specialDateDefinition.Day);

            if (date < minDate.Date ||
                (date == minDate.Date && !inclusive))
            {
                date = date.AddYears(1);
            }

            return(date);
        }