Allow nil values for custom attributes.

Author: natestedman

Attributed/Functions.swift

@@ -36,7 +36,7 @@ public func Join(strings: [AttributedStringConvertible]) -> AttributedStringConv
  - parameter attributes: The attributes to apply.
  - parameter strings:    The convertible strings.
  */
-public func Attributes(attributes: [String:AnyObject], _ strings: AttributedStringConvertible...)
+public func Attributes(attributes: [String:AnyObject?], _ strings: AttributedStringConvertible...)
     -> AttributedStringConvertible
 {
     return Attributes(attributes, strings)
@@ -50,7 +50,7 @@ public func Attributes(attributes: [String:AnyObject], _ strings: AttributedStri
  - parameter attributes: The attributes to apply.
  - parameter strings:    The convertible strings.
  */
-public func Attributes(attributes: [String:AnyObject], _ strings: [AttributedStringConvertible])
+public func Attributes(attributes: [String:AnyObject?], _ strings: [AttributedStringConvertible])
     -> AttributedStringConvertible
 {
     return NestedAttributedString(attributes: attributes, children: strings)
@@ -65,7 +65,7 @@ public func Attributes(attributes: [String:AnyObject], _ strings: [AttributedStr
  - parameter value:     The attribute value to apply.
  - parameter strings:   The convertible strings.
  */
-public func Attribute(attribute: String, _ value: AnyObject, _ strings: AttributedStringConvertible...)
+public func Attribute(attribute: String, _ value: AnyObject?, _ strings: AttributedStringConvertible...)
     -> AttributedStringConvertible
 {
     return Attribute(attribute, value, strings)
@@ -80,7 +80,7 @@ public func Attribute(attribute: String, _ value: AnyObject, _ strings: Attribut
  - parameter value:     The attribute value to apply.
  - parameter strings:   The convertible strings.
  */
-public func Attribute(attribute: String, _ value: AnyObject, _ strings: [AttributedStringConvertible])
+public func Attribute(attribute: String, _ value: AnyObject?, _ strings: [AttributedStringConvertible])
     -> AttributedStringConvertible
 {
     return Attributes([attribute: value], strings)

Attributed/NestedAttributedString.swift

@@ -14,7 +14,7 @@ import Foundation
 internal struct NestedAttributedString
 {
     /// The attributes to apply over this string's children.
-    let attributes: [String:AnyObject]
+    let attributes: [String:AnyObject?]
 
     /// The children of this attributed string.
     let children: [AttributedStringConvertible]

AttributedTests/AttributedTests.swift

@@ -59,4 +59,21 @@ class AttributedTests: XCTestCase
 
         XCTAssertEqual(attributed, mutable)
     }
+    
+    func testNilValue()
+    {
+        let attributed = ColorType.blueColor().foregroundAttribute(
+            "Test",
+            Attribute(NSForegroundColorAttributeName, nil,
+                "Test",
+                ColorType.greenColor().foregroundAttribute("Test")
+            )
+        ).attributedString
+        
+        let mutable = NSMutableAttributedString(string: "TestTestTest")
+        mutable.addAttribute(NSForegroundColorAttributeName, value: ColorType.blueColor(), range: NSMakeRange(0, 4))
+        mutable.addAttribute(NSForegroundColorAttributeName, value: ColorType.greenColor(), range: NSMakeRange(8, 4))
+        
+        XCTAssertEqual(attributed, mutable)
+    }
 }