halfopenstartinterval.swift

public struct HalfOpenStartInterval<Bound : Comparable> : IntervalType, Equatable, CustomStringConvertible, CustomDebugStringConvertible {
  public init(_ start: Bound, _ end: Bound) { (self.start, self.end) = (start, end) }
  public let start, end: Bound
  public var description: String {
    return String(reflecting: start) + ">.." + String(reflecting: end)
  }
  public var debugDescription: String { return description }
  @warn_unused_result
  public func contains(x: Bound) -> Bool { return x > start && x <= end }
  @warn_unused_result
  public func clamp(intervalToClamp: HalfOpenStartInterval<Bound>) -> HalfOpenStartInterval<Bound> {
    switch (intervalToClamp.start >= start, intervalToClamp.end <= end) {
    case (true, true)  : return intervalToClamp
    case (false, false): return self
    case (true, false) : return HalfOpenStartInterval(min(intervalToClamp.start, end), end)
    case (false, true) : return HalfOpenStartInterval(start, max(intervalToClamp.end, start))
    }
  }
  public var isEmpty: Bool { return start == end }
}

public func ==<B : Comparable>(lhs: HalfOpenStartInterval<B>, rhs: HalfOpenStartInterval<B>) -> Bool {
  return lhs.start == rhs.start && lhs.end == rhs.end
}