Merge pull request #10 from arttb/OptionalsSupport

Added support for optional values for dictionary encoder and decoder;

Author: tattn

Sources/DictionaryDecoder.swift

@@ -100,7 +100,13 @@ extension DictionaryDecoder {
             return try decoder.unbox(value, as: T.self)
         }
 
-        func decodeNil(forKey key: Key) throws -> Bool { throw decoder.notFound(key: key) }
+        func decodeNil(forKey key: Key) throws -> Bool {
+            guard let entry = self.container[key.stringValue] else {
+                throw decoder.notFound(key: key)
+            }
+
+            return entry is NSNull
+        }
         func decode(_ type: Bool.Type, forKey key: Key) throws -> Bool { return try _decode(type, forKey: key) }
         func decode(_ type: Int.Type, forKey key: Key) throws -> Int { return try _decode(type, forKey: key) }
         func decode(_ type: Int8.Type, forKey key: Key) throws -> Int8 { return try _decode(type, forKey: key) }
@@ -190,7 +196,13 @@ extension DictionaryDecoder {
 
         func decodeNil() throws -> Bool {
             try checkIndex(Any?.self)
-            return false
+
+            if self.container[self.currentIndex] is NSNull {
+                self.currentIndex += 1
+                return true
+            } else {
+                return false
+            }
         }
         func decode(_ type: Bool.Type) throws -> Bool { return try _decode(type) }
         func decode(_ type: Int.Type) throws -> Int { return try _decode(type) }

Sources/DictionaryEncoder.swift

@@ -74,7 +74,7 @@ extension DictionaryEncoder {
             storage.push(container: dictionary)
         }
 
-        func encodeNil(forKey key: Key) throws {}
+        func encodeNil(forKey key: Key) throws { set(NSNull(), forKey: key.stringValue) }
         func encode(_ value: Bool, forKey key: Key) throws { set(value, forKey: key.stringValue) }
         func encode(_ value: Int, forKey key: Key) throws { set(value, forKey: key.stringValue) }
         func encode(_ value: Int8, forKey key: Key) throws { set(value, forKey: key.stringValue) }
@@ -143,7 +143,7 @@ extension DictionaryEncoder {
             storage.push(container: array)
         }
 
-        func encodeNil() throws {}
+        func encodeNil() throws { push(NSNull()) }
         func encode(_ value: Bool) throws {}
         func encode(_ value: Int) throws { push(try encoder.box(value)) }
         func encode(_ value: Int8) throws { push(try encoder.box(value)) }
@@ -200,7 +200,7 @@ extension DictionaryEncoder {
             storage.push(container: array)
         }
 
-        func encodeNil() throws {}
+        func encodeNil() throws { storage.push(container: NSNull()) }
         func encode(_ value: Bool) throws { storage.push(container: value) }
         func encode(_ value: Int) throws { storage.push(container: value) }
         func encode(_ value: Int8) throws { storage.push(container: value) }