namespace System

{

public readonly struct Range : IEquatable<Range>

{

public Index Start { get; }

public Index End { get; }

private Range(Index start, Index end)

{

Start = start;

End = end;

}

public override bool Equals(object value)

{

if (value is Range)

{

Range r = (Range)value;

return r.Start.Equals(Start) && r.End.Equals(End);

}

return false;

}

public bool Equals(Range other) => other.Start.Equals(Start) && other.End.Equals(End);

public override int GetHashCode()

{

return Start.GetHashCode() ^ End.GetHashCode();

}

public override string ToString()

{

return Start + ".." + End;

}

public static Range Create(Index start, Index end) => new Range(start, end);

public static Range FromStart(Index start) => new Range(start, new Index(0, fromEnd: true));

public static Range ToEnd(Index end) => new Range(new Index(0, fromEnd: false), end);

public static Range All() => new Range(new Index(0, fromEnd: false), new Index(0, fromEnd: true));

}

}