lib/more_collections: add `clean` to `HashMap[23]`

[nit.git] / lib / more_collections.nit

diff --git a/lib/more_collections.nit b/lib/more_collections.nit
index bd441a1..f9b55af 100644 (file)
--- a/lib/more_collections.nit
+++ b/lib/more_collections.nit
@@ -29,15 +29,16 @@ module more_collections
 #     assert m.has_key("four")
 #     assert m["four"] == ['i', 'i', 'i', 'i']
 #     assert m["zzz"] == new Array[Char]
-class MultiHashMap[K: Object, V]
+class MultiHashMap[K, V]
        super HashMap[K, Array[V]]
 
        # Add `v` to the array associated with `k`.
        # 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
@@ -48,51 +49,74 @@ class MultiHashMap[K: Object, V]
                self[key] = res
                return res
        end
-
-       init do end
 end
 
 # Simple way to store an `HashMap[K1, HashMap[K2, V]]`
-class HashMap2[K1: Object, K2: Object, V]
-       private var level1: HashMap[K1, HashMap[K2, V]] = new HashMap[K1, HashMap[K2, V]]
+#
+# ~~~~
+# var hm2 = new HashMap2[Int, String, Float]
+# hm2[1, "one"] = 1.0
+# hm2[2, "two"] = 2.0
+# assert hm2[1, "one"] == 1.0
+# assert hm2[2, "not-two"] == null
+# ~~~~
+class HashMap2[K1, K2, V]
+       private var level1 = new HashMap[K1, HashMap[K2, V]]
 
        # Return the value associated to the keys `k1` and `k2`.
        # Return `null` if no such a value.
        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]]]`
-class HashMap3[K1: Object, K2: Object, K3: Object, V]
-       private var level1: HashMap[K1, HashMap2[K2, K3, V]] = new HashMap[K1, HashMap2[K2, K3, V]]
+#
+# ~~~~
+# var hm3 = new HashMap3[Int, String, Int, Float]
+# hm3[1, "one", 11] = 1.0
+# hm3[2, "two", 22] = 2.0
+# assert hm3[1, "one", 11] == 1.0
+# assert hm3[2, "not-two", 22] == null
+# ~~~~
+class HashMap3[K1, K2, K3, V]
+       private var level1 = new HashMap[K1, HashMap2[K2, K3, V]]
 
        # Return the value associated to the keys `k1`, `k2`, and `k3`.
        # Return `null` if no such a value.
        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
 
@@ -100,19 +124,68 @@ class HashMap3[K1: Object, K2: Object, K3: Object, 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.
-class DefaultMap[K: Object, V]
+#
+# ~~~~
+# var dm = new DefaultMap[String, Int](10)
+# assert dm["a"] == 10
+# ~~~~
+#
+# The default value is used when the key is not present.
+# And getting a default value does not register the key.
+#
+# ~~~~
+# assert dm["a"] == 10
+# assert dm.length == 0
+# assert dm.has_key("a") == false
+# ~~~~
+#
+# It also means that removed key retrieve the default value.
+#
+# ~~~~
+# dm["a"] = 2
+# assert dm["a"] == 2
+# dm.keys.remove("a")
+# assert dm["a"] == 10
+# ~~~~
+#
+# Warning: the default value is used as is, so using mutable object might
+# cause side-effects.
+#
+# ~~~~
+# var dma = new DefaultMap[String, Array[Int]](new Array[Int])
+#
+# dma["a"].add(65)
+# assert dma["a"] == [65]
+# assert dma.default == [65]
+# assert dma["c"] == [65]
+#
+# dma["b"] += [66]
+# assert dma["b"] == [65, 66]
+# assert dma.default == [65]
+# ~~~~
+class DefaultMap[K, V]
        super HashMap[K, V]
 
        # The default value.