Dactyloidae iOS initial commit

mobile/ios/Shared/Extensions/NSMutableAttributedStringExtensions.swift

@@ -0,0 +1,22 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import UIKit
+
+extension NSMutableAttributedString {
+    public func colorSubstring(_ substring: String, withColor color: UIColor) {
+        self.attributeSubstring(substring, forAttribute: NSForegroundColorAttributeName, withValue: color)
+    }
+
+    public func pitchSubstring(_ substring: String, withPitch pitch: Double) {
+        let pitchValue = NSNumber(value: pitch as Double)
+        self.attributeSubstring(substring, forAttribute: UIAccessibilitySpeechAttributePitch, withValue: pitchValue)
+    }
+
+    private func attributeSubstring(_ substring: String, forAttribute attribute: String, withValue value: AnyObject) {
+        let nsString = self.string as NSString
+        let range = nsString.range(of: substring)
+        self.addAttribute(attribute, value: value, range: range)
+    }
+}