feat: impl PeekingNext for {vec::Drain, array::IntoIter, string::Drain}

Author: aatifsyed

src/peeking_take_while.rs

@@ -105,6 +105,44 @@ impl<T> PeekingNext for ::alloc::vec::IntoIter<T> {
     }
 }
 
+#[cfg(feature = "use_alloc")]
+impl<'a, T> PeekingNext for ::alloc::vec::Drain<'a, T> {
+    fn peeking_next<F>(&mut self, accept: F) -> Option<Self::Item>
+    where
+        F: FnOnce(&Self::Item) -> bool,
+    {
+        match accept(self.as_slice().first()?) {
+            true => self.next(),
+            false => None,
+        }
+    }
+}
+
+#[cfg(feature = "use_alloc")]
+impl<'a> PeekingNext for ::alloc::string::Drain<'a> {
+    fn peeking_next<F>(&mut self, accept: F) -> Option<Self::Item>
+    where
+        F: FnOnce(&Self::Item) -> bool,
+    {
+        match accept(&self.as_str().chars().next()?) {
+            true => self.next(),
+            false => None,
+        }
+    }
+}
+
+impl<T, const N: usize> PeekingNext for ::core::array::IntoIter<T, N> {
+    fn peeking_next<F>(&mut self, accept: F) -> Option<Self::Item>
+    where
+        F: FnOnce(&Self::Item) -> bool,
+    {
+        match accept(self.as_slice().first()?) {
+            true => self.next(),
+            false => None,
+        }
+    }
+}
+
 impl<T: Clone> PeekingNext for RepeatN<T> {
     fn peeking_next<F>(&mut self, accept: F) -> Option<Self::Item>
     where