X-Git-Url: http://nitlanguage.org

diff --git a/lib/more_collections.nit b/lib/more_collections.nit
index 6396ec2..f9b55af 100644
--- a/lib/more_collections.nit
+++ b/lib/more_collections.nit
@@ -36,8 +36,9 @@ class MultiHashMap[K, V]
 	# If there is no array associated, then create it.
 	fun add_one(k: K, v: V)
 	do
-		if self.has_key(k) then
-			self[k].add(v)
+		var x = self.get_or_null(k)
+		if x != null then
+			x.add(v)
 		else
 			self[k] = [v]
 		end
@@ -67,25 +68,34 @@ class HashMap2[K1, K2, V]
 	fun [](k1: K1, k2: K2): nullable V
 	do
 		var level1 = self.level1
-		if not level1.has_key(k1) then return null
-		var level2 = level1[k1]
-		if not level2.has_key(k2) then return null
-		return level2[k2]
+		var level2 = level1.get_or_null(k1)
+		if level2 == null then return null
+		return level2.get_or_null(k2)
 	end
 
 	# Set `v` the value associated to the keys `k1` and `k2`.
 	fun []=(k1: K1, k2: K2, v: V)
 	do
 		var level1 = self.level1
-		var level2: HashMap[K2, V]
-		if not level1.has_key(k1) then
+		var level2 = level1.get_or_null(k1)
+		if level2 == null then
 			level2 = new HashMap[K2, V]
 			level1[k1] = level2
-		else
-			level2 = level1[k1]
 		end
 		level2[k2] = v
 	end
+
+	# Remove the item at `k1` and `k2`
+	fun remove_at(k1: K1, k2: K2)
+	do
+		var level1 = self.level1
+		var level2 = level1.get_or_null(k1)
+		if level2 == null then return
+		level2.keys.remove(k2)
+	end
+
+	# Remove all items
+	fun clear do level1.clear
 end
 
 # Simple way to store an `HashMap[K1, HashMap[K2, HashMap[K3, V]]]`
@@ -105,8 +115,8 @@ class HashMap3[K1, K2, K3, V]
 	fun [](k1: K1, k2: K2, k3: K3): nullable V
 	do
 		var level1 = self.level1
-		if not level1.has_key(k1) then return null
-		var level2 = level1[k1]
+		var level2 = level1.get_or_null(k1)
+		if level2 == null then return null
 		return level2[k2, k3]
 	end
 
@@ -114,15 +124,25 @@ class HashMap3[K1, K2, K3, V]
 	fun []=(k1: K1, k2: K2, k3: K3, v: V)
 	do
 		var level1 = self.level1
-		var level2: HashMap2[K2, K3, V]
-		if not level1.has_key(k1) then
+		var level2 = level1.get_or_null(k1)
+		if level2 == null then
 			level2 = new HashMap2[K2, K3, V]
 			level1[k1] = level2
-		else
-			level2 = level1[k1]
 		end
 		level2[k2, k3] = v
 	end
+
+	# Remove the item at `k1`, `k2` and `k3`
+	fun remove_at(k1: K1, k2: K2, k3: K3)
+	do
+		var level1 = self.level1
+		var level2 = level1.get_or_null(k1)
+		if level2 == null then return
+		level2.remove_at(k2, k3)
+	end
+
+	# Remove all items
+	fun clear do level1.clear
 end
 
 # A map with a default value.