Removed dependencies on isKindOfClass:.

Author: Patrick Thomson

src/YKEmitter.m

@@ -19,7 +19,6 @@ - (id)init
         yaml_emitter_initialize(&emitter);
 
         buffer = [NSMutableData data];
-        // I am overjoyed that this works.
         // Coincidentally, the order of arguments to CFDataAppendBytes are just right
         // such that if I pass the buffer as the data parameter, I can just use 
         // a pointer to CFDataAppendBytes to tell the emitter to write to the NSMutableData.
@@ -34,10 +33,10 @@ - (void)emitItem:(id)item
     // Create and initialize a document to hold this.
     yaml_document_t document;
     memset(&document, 0, sizeof(document));
-    // The double usage of !usesExplicitDelimiters is to indicate that both the start and the end of the 
-    // document should be delimited, if at all.
+    // The double usage of !usesExplicitDelimiters corresponds to explicitly
+	// delimiting the start and end of various documents.
     yaml_document_initialize(&document, NULL, NULL, NULL, !usesExplicitDelimiters, !usesExplicitDelimiters);
-    
+    // TODO: Make this into a proper private method.
     [self _writeItem:item toDocument:&document];
     yaml_emitter_dump(&emitter, &document);
     yaml_document_delete(&document);
@@ -46,23 +45,27 @@ - (void)emitItem:(id)item
 - (int)_writeItem:(id)item toDocument:(yaml_document_t *)doc;
 {
 	int nodeID = 0;
-	if([item isKindOfClass:[NSArray class]] || [item isKindOfClass:[NSSet class]]) {
-		// emit beginning sequence
-		nodeID = yaml_document_add_sequence(doc, (yaml_char_t *)YAML_DEFAULT_SEQUENCE_TAG, YAML_ANY_SEQUENCE_STYLE);
-		for(id subitem in item) {
-			int newItem = [self _writeItem:subitem toDocument:doc];
-			yaml_document_append_sequence_item(doc, nodeID, newItem);
-		}
-	} else if([item isKindOfClass:[NSDictionary class]]) {
-		// emit beginning mapping
+	// #keyEnumerator covers NSMapTable/NSHashTable/NSDictionary 
+	if([item respondsToSelector:@selector(keyEnumerator)]) {
+		// Add a mapping node.
 		nodeID = yaml_document_add_mapping(doc, (yaml_char_t *)YAML_DEFAULT_MAPPING_TAG, YAML_ANY_MAPPING_STYLE);
 		for(id key in item) {
 			int keyID = [self _writeItem:key toDocument:doc];
 			int valueID = [self _writeItem:[item objectForKey:key] toDocument:doc];
 			yaml_document_append_mapping_pair(doc, nodeID, keyID, valueID);
 		}
+	// #objectEnumerator covers NSSet/NSArray.
+	} else if([item respondsToSelector:@selector(objectEnumerator)]) {
+		// emit beginning sequence
+		nodeID = yaml_document_add_sequence(doc, (yaml_char_t *)YAML_DEFAULT_SEQUENCE_TAG, YAML_ANY_SEQUENCE_STYLE);
+		for(id subitem in item) {
+			int newItem = [self _writeItem:subitem toDocument:doc];
+			yaml_document_append_sequence_item(doc, nodeID, newItem);
+		}
+	// Everything else is a scalar.
 	} else {
 		// TODO: Add optional support for tagging emitted items.
+		// TODO: Wrap long lines.
 		nodeID = yaml_document_add_scalar(doc, (yaml_char_t *)YAML_DEFAULT_SCALAR_TAG, (yaml_char_t*)[[item description] UTF8String], strlen([[item description] UTF8String]), YAML_ANY_SCALAR_STYLE);
 	}
 	return nodeID;