Compare keywords like Clojure

Compare by ns then name.

MPEdn/MPEdnKeyword.h

@@ -68,6 +68,8 @@
  */
 - (NSString *) stringValue;
 
+- (NSComparisonResult) compare: (MPEdnKeyword *) object;
+
 @end
 
 @interface NSString (MPEdn)

MPEdn/MPEdnKeyword.m

@@ -22,6 +22,7 @@
 @implementation MPEdnKeyword
 {
   NSString *name;
+  NSString *namespace;
 }
 
 + (void) initialize
@@ -82,8 +83,14 @@ - (instancetype) initWithName: (NSString *) initName
   if (self = [super init])
   {
     name = initName;
+    CFIndex nsIndex = [name rangeOfString: @"/"].location;
+
+    if (nsIndex == NSNotFound)
+      namespace = @"";
+    else
+      namespace = [name substringToIndex: nsIndex];
   }
-  
+
   return self;
 }
 
@@ -109,7 +116,12 @@ - (BOOL) isEqual: (id) object
 
 - (NSComparisonResult) compare: (MPEdnKeyword *) object
 {
-  return [name compare: [object ednName]];
+  NSComparisonResult nsCompare = [self->namespace compare: object->namespace];
+
+  if (nsCompare == 0)
+    return [self->name compare: object->name];
+  else
+    return nsCompare;
 }
 
 - (NSString *) description

MPEdnTests/MPEdnParserTests.m

@@ -150,6 +150,10 @@ - (void) testKeywords
 
   // keywords as strings
   XCTAssertEqualObjects ([@":b" ednStringToObjectNoKeywords], @"b", @"Equal keyword");
+
+  // test comparison uses namespace like Clojure does (this test doesn't really belong here...)
+  XCTAssert ([[@"z" ednKeyword] compare: [@"a/a" ednKeyword]] < 0, @"Compare using ns");
+  XCTAssert ([[@"a/z" ednKeyword] compare: [@"z/a" ednKeyword]] < 0, @"Compare using ns");
 }
 
 - (void) testSets