From 8b19ab94c76d2eec51d2a942099f5b2ce2621df2 Mon Sep 17 00:00:00 2001
From: Michael Sippel <micha@fragmental.art>
Date: Tue, 31 Aug 2021 02:57:42 +0200
Subject: [PATCH] sequence: add filter_map()

could be more efficient
---
 nested/src/sequence/map.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/nested/src/sequence/map.rs b/nested/src/sequence/map.rs
index a537fd7..0849382 100644
--- a/nested/src/sequence/map.rs
+++ b/nested/src/sequence/map.rs
@@ -33,6 +33,18 @@ impl<Item: 'static> OuterViewPort<dyn SequenceView<Item = Item>> {
         port.inner().set_view(Some(map));
         port.into_outer()
     }
+
+    pub fn filter_map<
+        DstItem: Clone + 'static,
+        F: Fn(&Item) -> Option<DstItem> + Send + Sync + 'static
+    >(
+        &self,
+        f: F
+    ) -> OuterViewPort<dyn SequenceView<Item = DstItem>> {
+        self.map(f)
+            .filter(|x| x.is_some())
+            .map(|x| x.clone().unwrap())
+    }
 }
 
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