add AdvanceWhile trait for conditional iterator advancement

src/iter.rs

@@ -42,3 +42,20 @@ pub trait NextIf<I>: Iterator<Item = I> + Clone {
 }
 
 impl<I, T> NextIf<I> for T where T: Iterator<Item = I> + Clone {}
+
+pub trait AdvanceWhile<I>: Iterator<Item = I> + Clone {
+    /// Advance the iterator while `pred` returns true.
+    fn advance_while<F>(&mut self, mut pred: F)
+    where
+        F: FnMut(&Self::Item) -> bool,
+    {
+        loop {
+            match self.next_if(&mut pred) {
+                Some(_) => {}
+                None => break,
+            }
+        }
+    }
+}
+
+impl<I, T> AdvanceWhile<I> for T where T: Iterator<Item = I> + Clone {}