Shared Code/CalculatorKitExtensions.swift
/* |
Copyright (C) 2018 Apple Inc. All Rights Reserved. |
See LICENSE.txt for this sample’s licensing information |
Abstract: |
Creates an extension for the String class. |
*/ |
import Foundation |
extension String { |
/// Determines whether the string is the Delete charater. |
var isDelete: Bool { |
return (self == "D") |
} |
/// Determines whether the string is a period. |
var isPeriod: Bool { |
return (self == ".") |
} |
/// Determines whether the string is the Clear charater. |
var isClear: Bool { |
return (self == "C") |
} |
/// Determines whether the string is a period or a number between 0 and 9. |
var isValidDigit: Bool { |
let digits = "0123456789." |
return digits.contains(self) |
} |
/// Determines whether the string is an operator such as +, -, *, or /. |
var isOperator: Bool { |
let operators = "+-*/" |
return operators.contains(self) |
} |
/// Determines whether the string is an equal sign. |
var isEqualSign: Bool { |
return (self == "=") |
} |
/// Determines whether a string is a valid character such as a digit, a. |
var isValidCharacter: Bool { |
return ( isValidDigit || isOperator || isDelete || isClear || isPeriod || isEqualSign) |
} |
} |
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