diff --git a/hashtable.c b/hashtable.c
index ba4356d..fc42eca 100644
--- a/hashtable.c
+++ b/hashtable.c
@@ -16,10 +16,16 @@ bool hashtable_expand(hashtable* table) {
 	temptable.filled = 0;
 	temptable.items = newitems;
 	for (size_t i = 0; i < oldcapacity; i++) {
-		if (olditems[i].name == NULL)
+		if (olditems[i].name == NULL || olditems[i].name == (void*)1)
 			continue;
-		size_t index = hashtable_insert(&temptable, olditems[i].name);
-		newitems[index].data = olditems[i].data;
+		size_t_optional index = hashtable_insert(&temptable, olditems[i].name);
+		if (!index.exists) {
+			hashtable_item* array = temptable.items;
+			for (size_t i = 0; i < temptable.capacity; i++)
+				free(array[i].name);
+			return false;
+		}
+		newitems[index.sizet].data = olditems[i].data;
 	}
 	table->capacity = newcapacity;
 	table->filled = temptable.filled;
@@ -29,6 +35,8 @@ bool hashtable_expand(hashtable* table) {
 
 hashtable* hashtable_create(void) {
 	hashtable* table = malloc(sizeof(hashtable));
+	if (table == NULL)
+		return NULL;
 	table->capacity = 16;
 	table->items = calloc(16, sizeof(hashtable_item));
 	return table;
@@ -40,29 +48,29 @@ size_t_optional hashtable_key(hashtable* table, char* name) {
 	while (1) {
 		if (array[index].name == NULL) 
 			return (size_t_optional) { false, 0 }; 
-		if (!strcmp(name, array[index].name))
-			return (size_t_optional) { true, index };
-		else
-			index = (index + 1) & (table->capacity - 1);
+		if (array[index].name != (void*)(1))
+			if (!strcmp(name, array[index].name))
+				return (size_t_optional) { true, index };
+		index = (index + 1) & (table->capacity - 1);
 	}
 }
 
-size_t hashtable_insert(hashtable* table, char* name) {
+size_t_optional hashtable_insert(hashtable* table, char* name) {
 	size_t index = sdbm(name) & (table->capacity - 1);
 	hashtable_item* array = table->items;
 	if ((table->capacity >> 2) * 3 < table->filled) {
 		hashtable_expand(table);
 	}
 	while (1) {
-		if (array[index].name == NULL) {
+		if (array[index].name == NULL || array[index].name == (void*)1) {
 			array[index].name = malloc(strlen(name) + sizeof(name));
 			strcpy(array[index].name, name);
 			table->filled++;
-			return index;
+			return (size_t_optional) {true, index};
 		}
 		else
 			if (!strcmp(array[index].name, name))
-				return index;
+				return (size_t_optional) {true, index};
 			else
 				index = (index + 1) & (table->capacity - 1);
 	}
@@ -83,6 +91,22 @@ void* hashtable_get(hashtable* table, char* name) {
 }
 
 void hashtable_set(hashtable* table, char* name, void* data) {
-	size_t index = hashtable_insert(table, name);
-	table->items[index].data = data;
+	size_t_optional index = hashtable_insert(table, name);
+	if (index.exists)
+		table->items[index.sizet].data = data;
+}
+
+void hashtable_delete(hashtable* table, char* name) {
+	size_t_optional index = hashtable_key(table, name);
+	if (index.exists) {
+		table->items[index.sizet].name = (void*)1;
+		table->filled--;
+	}
+}
+
+void hashtable_forall(hashtable* table, void (*callback)(char*, void*)) {
+	size_t capacity = table->capacity;
+	hashtable_item* items = table->items;
+	for (size_t i = 0; i < capacity; i++)
+		callback(items[i].name, items[i].data);
 }
diff --git a/hashtable.h b/hashtable.h
index 0c4c575..5497be2 100644
--- a/hashtable.h
+++ b/hashtable.h
@@ -23,8 +23,12 @@ void hashtable_destroy(hashtable*);
 
 size_t_optional hashtable_key(hashtable*, char*);
 
-size_t hashtable_insert(hashtable*, char*);
+size_t_optional hashtable_insert(hashtable*, char*);
 
 void* hashtable_get(hashtable* table, char* name);
 
 void hashtable_set(hashtable* table, char* name, void* data);
+
+void hashtable_delete(hashtable*, char*);
+
+void hashtable_forall(hashtable*, void (*)(char*, void*));