Swift String extension to use NSString's 'bool' interpretation rules.

String+BoolInterpreter.swift

import Foundation

extension String {
   /// Retrieve the contents of the string as a Bool value.
   ///
   /// This property is true on encountering one of "Y", "y", "T", "t", or a digit 1-9—the method ignores any trailing characters. This property is false if the receiver doesn’t begin with a valid decimal text representation of a number.
   ///
   /// The property assumes a decimal representation and skips whitespace at the beginning of the string. It also skips initial whitespace characters, or optional -/+ sign followed by zeroes.
   ///
   /// See: [NSString boolValue](https://developer.apple.com/documentation/foundation/nsstring/1409420-boolvalue)
   var boolValue: Bool {
      return (self as NSString).boolValue
   }
}