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//
// Rank.swift
// Sage
//
// Copyright 2016-2017 Nikolai Vazquez
// Modified by SuperGeroy
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
/// A chess board rank.
///
/// `Rank`s refer to the eight rows of a chess board, beginning with 1 at the bottom and ending with 8 at the top.
public enum Rank: Int, Comparable, CustomStringConvertible {
/// A direction in rank.
public enum Direction {
/// Up direction.
case up
/// Down direction.
case down
}
/// Rank 1.
case one = 1
/// Rank 2.
case two = 2
/// Rank 3.
case three = 3
/// Rank 4.
case four = 4
/// Rank 5.
case five = 5
/// Rank 6.
case six = 6
/// Rank 7.
case seven = 7
/// Rank 8.
case eight = 8
}
extension Rank {
/// An array of all ranks.
public static let all: [Rank] = [1, 2, 3, 4, 5, 6, 7, 8]
/// The row index of `self`.
public var index: Int {
return rawValue - 1
}
/// A textual representation of `self`.
public var description: String {
return String(rawValue)
}
/// Create an instance from an integer value.
public init?(_ value: Int) {
self.init(rawValue: value)
}
/// Create a `Rank` from a zero-based row index.
public init?(index: Int) {
self.init(rawValue: index + 1)
}
/// Creates the starting `Rank` for the color.
public init(startFor color: Color) {
self = color.isWhite ? 1 : 8
}
/// Creates the ending `Rank` for the color.
public init(endFor color: Color) {
self = color.isWhite ? 8 : 1
}
/// Returns a rank from advancing `self` by `value` with respect to `color`.
public func advanced(by value: Int, for color: Color = .white) -> Rank? {
return Rank(rawValue: rawValue + (color.isWhite ? value : -value))
}
/// The next rank after `self`.
public func next() -> Rank? {
return Rank(rawValue: (rawValue + 1))
}
/// The previous rank to `self`.
public func previous() -> Rank? {
return Rank(rawValue: (rawValue - 1))
}
/// The opposite rank of `self`.
public func opposite() -> Rank {
return Rank(rawValue: 9 - rawValue)!
}
/// The files from `self` to `other`.
public func to(_ other: Rank) -> [Rank] {
return _to(other)
}
/// The files between `self` and `other`.
public func between(_ other: Rank) -> [Rank] {
return _between(other)
}
}
extension Rank: ExpressibleByIntegerLiteral { }
extension Rank {
/// Create an instance initialized to `value`.
public init(integerLiteral value: Int) {
guard let rank = Rank(rawValue: value) else {
fatalError("Rank value not within 1 and 8, inclusive")
}
self = rank
}
}
/// Returns `true` if one rank is higher than the other.
public func < (lhs: Rank, rhs: Rank) -> Bool {
return lhs.rawValue < rhs.rawValue
}
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