From 8cb4f00733b702bd54fff29c479bcc706d083d5e Mon Sep 17 00:00:00 2001
From: Philippe-Cholet <phcholet@orange.fr>
Date: Wed, 8 Nov 2023 12:11:06 +0100
Subject: [PATCH 1/2] `Positions::fold`

---
 src/adaptors/mod.rs | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/adaptors/mod.rs b/src/adaptors/mod.rs
index e925db51d..7f6ff95a1 100644
--- a/src/adaptors/mod.rs
+++ b/src/adaptors/mod.rs
@@ -1081,6 +1081,21 @@ where
     fn size_hint(&self) -> (usize, Option<usize>) {
         (0, self.iter.size_hint().1)
     }
+
+    fn fold<B, G>(self, init: B, mut func: G) -> B
+    where
+        G: FnMut(B, Self::Item) -> B,
+    {
+        let mut count = self.count;
+        let mut f = self.f;
+        self.iter.fold(init, |mut acc, val| {
+            if f(val) {
+                acc = func(acc, count);
+            }
+            count += 1;
+            acc
+        })
+    }
 }
 
 impl<I, F> DoubleEndedIterator for Positions<I, F>

From d0ee7e071c129a50b2d0bc336132a31012544ba3 Mon Sep 17 00:00:00 2001
From: Philippe-Cholet <phcholet@orange.fr>
Date: Fri, 24 Nov 2023 10:47:02 +0100
Subject: [PATCH 2/2] `Positions::rfold`

---
 src/adaptors/mod.rs | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/adaptors/mod.rs b/src/adaptors/mod.rs
index 7f6ff95a1..52ee4800c 100644
--- a/src/adaptors/mod.rs
+++ b/src/adaptors/mod.rs
@@ -1111,6 +1111,21 @@ where
         }
         None
     }
+
+    fn rfold<B, G>(self, init: B, mut func: G) -> B
+    where
+        G: FnMut(B, Self::Item) -> B,
+    {
+        let mut count = self.count + self.iter.len();
+        let mut f = self.f;
+        self.iter.rfold(init, |mut acc, val| {
+            count -= 1;
+            if f(val) {
+                acc = func(acc, count);
+            }
+            acc
+        })
+    }
 }
 
 impl<I, F> FusedIterator for Positions<I, F>