/// <summary>
/// 获取一卦的彖辞。
/// Get the text in Tuanzhuan of a hexagram.
/// </summary>
/// <param name="hexagram">
/// 卦。
/// The hexagram.
/// </param>
/// <returns>
/// 彖辞。
/// The text in Tuanzhuan.
/// </returns>
/// <exception cref="ArgumentNullException">
/// <paramref name="hexagram"/> 为 <c>null</c> 。
/// <paramref name="hexagram"/> is <c>null</c>.
/// </exception>
public string this[ZhouyiHexagram hexagram]
{
get
{
if (hexagram is null)
{
throw new ArgumentNullException(nameof(hexagram));
}
return(this.translation.TuanTexts[hexagram.Index - 1]);
}
}
public string ApplyPattern(ZhouyiHexagram hexagram)
{
IEnumerable <string> BuildPlaceholders()
{
yield return(Environment.NewLine);
yield return(this.numbers.Ordinal[hexagram.Index - 1]);
yield return(hexagram.Name);
yield return(hexagram.Text);
yield return(hexagram.LowerTrigram.Name);
yield return(hexagram.LowerTrigram.Nature);
yield return(hexagram.UpperTrigram.Name);
yield return(hexagram.UpperTrigram.Nature);
yield return(this.ApplyPattern(hexagram.FirstLine));
yield return(this.ApplyPattern(hexagram.SecondLine));
yield return(this.ApplyPattern(hexagram.ThirdLine));
yield return(this.ApplyPattern(hexagram.FourthLine));
yield return(this.ApplyPattern(hexagram.FifthLine));
yield return(this.ApplyPattern(hexagram.SixthLine));
if (hexagram.ApplyNinesOrApplySixes is not null)
{
yield return(this.ApplyPattern(hexagram.ApplyNinesOrApplySixes));
}
else
{
yield return(string.Empty);
}
}
return(string.Format(
hexagram.UpperTrigram.Equals(hexagram.LowerTrigram) ?
this.patterns.PureHexagramsToString :
this.patterns.HexagramsToString, BuildPlaceholders().ToArray()));
}
