From a5024444119b63902fb1e600e2432b86ad2f1cf5 Mon Sep 17 00:00:00 2001
From: skilesare <austin.fatheree@gmail.com>
Date: Thu, 19 May 2022 20:00:47 -0500
Subject: [PATCH] Update StableRBTree.mo

add keys, vals, keysRev and valsRev
---
 src/StableRBTree.mo | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/src/StableRBTree.mo b/src/StableRBTree.mo
index 16b072b..2e45cd7 100644
--- a/src/StableRBTree.mo
+++ b/src/StableRBTree.mo
@@ -169,12 +169,38 @@ module {
   /// iterator is persistent, like the tree itself
   public func entries<K, V>(tree: Tree<K, V>) : I.Iter<(K, V)> { iter(tree, #fwd) };
 
+    /// An `Iter` over the keys.
+    ///
+    /// Each iterator gets a _persistent view_ of the mapping, independent of concurrent updates to the iterated map.
+    public func keys<K, V>(tree: Tree<K,V>) : I.Iter<K>
+    { I.map(entries(tree), func (kv : (K, V)) : K { kv.0 }) };
+
+    /// An `Iter` over the values.
+    ///
+    /// Each iterator gets a _persistent view_ of the mapping, independent of concurrent updates to the iterated map.
+    public func vals<K, V>(tree: Tree<K,V>) : I.Iter<V>
+    { I.map(entries(tree), func (kv : (K, V)) : V { kv.1 }) };
+
   /// An iterator for the key-value entries of the map, in descending key order.
   ///
   /// iterator is persistent, like the tree itself
   public func entriesRev<K, V>(tree: Tree<K, V>) : I.Iter<(K, V)> { iter(tree, #bwd) };
 
 
+/// An `Iter` over the keys.
+    ///
+    /// Each iterator gets a _persistent view_ of the mapping, independent of concurrent updates to the iterated map.
+    public func keysRev<K, V>(tree: Tree<K,V>) : I.Iter<K>
+    { I.map(entriesRev(tree), func (kv : (K, V)) : K { kv.0 }) };
+
+    /// An `Iter` over the values.
+    ///
+    /// Each iterator gets a _persistent view_ of the mapping, independent of concurrent updates to the iterated map.
+    public func valsRev<K, V>(tree: Tree<K,V>) : I.Iter<V>
+    { I.map(entriesRev(tree), func (kv : (K, V)) : V { kv.1 }) };
+
+
+
 
   type IterRep<K, V> = List.List<{ #tr:Tree<K, V>; #kv:(K, ?V) }>;