1 files changed, 190 insertions, 0 deletions
diff --git a/Sources/SwiftChessNeo/File.swift b/Sources/SwiftChessNeo/File.swift
new file mode 100644
index 0000000..158eee7
--- /dev/null
+++ b/Sources/SwiftChessNeo/File.swift
@@ -0,0 +1,190 @@
+//
+//  File.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 file.
+///
+/// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
+public enum File: Int, Comparable, CustomStringConvertible {
+
+    /// A direction in file.
+    public enum Direction {
+
+        /// Left direction.
+        case left
+
+        /// Right direction.
+        case right
+
+    }
+
+    /// File "A".
+    case a = 1
+
+    /// File "B".
+    case b = 2
+
+    /// File "C".
+    case c = 3
+
+    /// File "D".
+    case d = 4
+
+    /// File "E".
+    case e = 5
+
+    /// File "F".
+    case f = 6
+
+    /// File "G".
+    case g = 7
+
+    /// File "H".
+    case h = 8
+
+    /// A regardless of Swift version.
+    internal static let _a = File.a
+
+    /// B regardless of Swift version.
+    internal static let _b = File.b
+
+    /// C regardless of Swift version.
+    internal static let _c = File.c
+
+    /// D regardless of Swift version.
+    internal static let _d = File.d
+
+    /// E regardless of Swift version.
+    internal static let _e = File.e
+
+    /// F regardless of Swift version.
+    internal static let _f = File.f
+
+    /// G regardless of Swift version.
+    internal static let _g = File.g
+
+    /// H regardless of Swift version.
+    internal static let _h = File.h
+
+}
+
+extension File {
+
+    /// An array of all files.
+    public static let all: [File] = [.a, .b, .c, .d, .e, .f, .g, .h]
+
+    /// The column index of `self`.
+    public var index: Int {
+        return rawValue - 1
+    }
+
+    /// A textual representation of `self`.
+    public var description: String {
+        return String(character)
+    }
+
+    /// The character value of `self`.
+    public var character: Character {
+        switch self {
+            case .a: return "a"
+            case .b: return "b"
+            case .c: return "c"
+            case .d: return "d"
+            case .e: return "e"
+            case .f: return "f"
+            case .g: return "g"
+            case .h: return "h"
+        }
+    }
+
+    /// Create an instance from a character value.
+    public init?(_ character: Character) {
+        switch character {
+            case "A", "a": self = .a
+            case "B", "b": self = .b
+            case "C", "c": self = .c
+            case "D", "d": self = .d
+            case "E", "e": self = .e
+            case "F", "f": self = .f
+            case "G", "g": self = .g
+            case "H", "h": self = .h
+            default: return nil
+        }
+    }
+
+    /// Create a `File` from a zero-based column index.
+    public init?(index: Int) {
+        self.init(rawValue: index + 1)
+    }
+
+    /// Returns a rank from advancing `self` by `value`.
+    public func advanced(by value: Int) -> File? {
+        return File(rawValue: rawValue + value)
+    }
+
+    /// The next file after `self`.
+    public func next() -> File? {
+        return File(rawValue: (rawValue + 1))
+    }
+
+    /// The previous file to `self`.
+    public func previous() -> File? {
+        return File(rawValue: (rawValue - 1))
+    }
+
+    /// The opposite file of `self`.
+    public func opposite() -> File {
+        return File(rawValue: 9 - rawValue)!
+    }
+
+    /// The files from `self` to `other`.
+    public func to(_ other: File) -> [File] {
+        return _to(other)
+    }
+
+    /// The files between `self` and `other`.
+    public func between(_ other: File) -> [File] {
+        return _between(other)
+    }
+
+}
+
+extension File: ExpressibleByExtendedGraphemeClusterLiteral { }
+
+extension File {
+
+    /// Create an instance initialized to `value`.
+    public init(unicodeScalarLiteral value: Character) {
+        guard let file = File(value) else {
+            fatalError("File value not within \"A\" and \"H\" or \"a\" and \"h\", inclusive")
+        }
+        self = file
+    }
+
+    /// Create an instance initialized to `value`.
+    public init(extendedGraphemeClusterLiteral value: Character) {
+        self.init(unicodeScalarLiteral: value)
+    }
+
+}
+
+/// Returns `true` if one file is further left than the other.
+public func < (lhs: File, rhs: File) -> Bool {
+    return lhs.rawValue < rhs.rawValue
+}