devedbox/Commander

//
//  Collection+.swift
//  Utility
//
//  Created by devedbox on 2018/11/10.
//
//  Permission is hereby granted, free of charge, to any person obtaining a copy
//  of this software and associated documentation files (the "Software"), to deal
//  in the Software without restriction, including without limitation the rights
//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//  copies of the Software, and to permit persons to whom the Software is
//  furnished to do so, subject to the following conditions:
//
//  The above copyright notice and this permission notice shall be included in all
//  copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
//  SOFTWARE.
//

// MARK: - Array.

extension Array where Element: RangeReplaceableCollection {
  /// Appends the given element to the receiver's last collection element.
  public mutating func lastAppend(_ element: Element.Element) {
    guard var last = popLast() else {
      return
    }
    
    last.append(element)
    append(last)
  }
}

// MARK: - Collection.

extension Collection {
  /// Returns a bool value indicates if the collection is containing only one element.
  public var isSingle: Bool {
    guard !isEmpty else {
      return false
    }
    return index(after: startIndex) == endIndex
  }
}