Implement split_initiator, split_ends, and split_once variants for string slices

Author: Jules Bertholet

library/alloc/src/str.rs

@@ -69,8 +69,8 @@ pub use core::str::{Matches, RMatches};
 pub use core::str::{RSplit, Split};
 #[unstable(feature = "split_inclusive_variants", issue = "none")]
 pub use core::str::{
-    RSplitInclusive, RSplitLeftInclusive, RSplitNInclusive, RSplitNLeftInclusive,
-    SplitLeftInclusive, SplitNInclusive, SplitNLeftInclusive,
+    RSplitInclusive, RSplitLeftInclusive, RSplitNInclusive, RSplitNLeftInclusive, SplitEnds,
+    SplitInitiator, SplitLeftInclusive, SplitNInclusive, SplitNLeftInclusive,
 };
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use core::str::{RSplitN, SplitN};

library/core/src/slice/iter/macros.rs

@@ -776,8 +776,7 @@ macro_rules! iter_n {
         #[$stability]
         impl<'a, T: 'a, P> $clone for $iter_n<'a, T, P>
         where
-            P: FnMut(&T) -> bool,
-            $inner<'a, T, P>: Clone,
+            P: Clone + FnMut(&T) -> bool,
         {
             fn clone(&self) -> Self {
                 Self { inner: self.inner.clone() }
@@ -788,7 +787,7 @@ macro_rules! iter_n {
         #[$stability]
         impl<T: fmt::Debug, P> fmt::Debug for $iter_n<'_, T, P>
         where
-            P: Clone + FnMut(&T) -> bool,
+            P: FnMut(&T) -> bool,
         {
             fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
                 f.debug_struct($str).field("inner", &self.inner).finish()

library/core/src/str/iter.rs

@@ -871,6 +871,35 @@ generate_pattern_iterators! {
     delegate double ended;
 }
 
+split_internal! {
+    SplitInitiatorInternal {
+        debug: "SplitInitiatorInternal",
+        skip_leading_empty: skip_leading_empty,
+        include_leading: false,
+        include_trailing: false,
+    }
+}
+
+generate_pattern_iterators! {
+    forward:
+        #[unstable(feature = "split_inclusive_variants", issue = "none")]
+        #[fused(unstable(feature = "split_inclusive_variants", issue = "none"))]
+        /// Created with the method [`split_initiator`].
+        ///
+        /// [`split_initiator`]: str::split_initiator
+        struct SplitInitiator;
+    reverse:
+        #[unstable(feature = "split_inclusive_variants", issue = "none")]
+        #[fused(unstable(feature = "split_inclusive_variants", issue = "none"))]
+        /// Created with the method [`rsplit_initiator`].
+        ///
+        /// [`rsplit_initiator`]: str::rsplit_initiator
+        struct RSplitInitiator;
+    internal:
+        SplitInitiatorInternal yielding (&'a str);
+    delegate double ended;
+}
+
 split_internal! {
     SplitTerminatorInternal {
         debug: "SplitTerminatorInternal",
@@ -900,6 +929,36 @@ generate_pattern_iterators! {
     delegate double ended;
 }
 
+split_internal! {
+    SplitEndsInternal {
+        debug: "SplitEndsInternal",
+        skip_leading_empty: skip_leading_empty,
+        skip_trailing_empty: skip_trailing_empty,
+        include_leading: false,
+        include_trailing: false,
+    }
+}
+
+generate_pattern_iterators! {
+    forward:
+        #[unstable(feature = "split_inclusive_variants", issue = "none")]
+        #[fused(unstable(feature = "split_inclusive_variants", issue = "none"))]
+        /// Created with the method [`split_ends`].
+        ///
+        /// [`split_ends`]: str::split_ends
+        struct SplitEnds;
+    reverse:
+        #[unstable(feature = "split_inclusive_variants", issue = "none")]
+        #[fused(unstable(feature = "split_inclusive_variants", issue = "none"))]
+        /// Created with the method [`rsplit_ends`].
+        ///
+        /// [`rsplit_ends`]: str::rsplit_ends
+        struct RSplitEnds;
+    internal:
+        SplitEndsInternal yielding (&'a str);
+    delegate double ended;
+}
+
 impl<'a, P: Pattern<'a>> SplitTerminator<'a, P> {
     /// Returns remainder of the split string
     ///