add move_prev_long_word_end and extend_prev_long_word_end (#6905)

1 files changed, 104 insertions, 3 deletions

diff --git a/helix-core/src/movement.rs b/helix-core/src/movement.rs
index b44d149f..003a1f37 100644
--- a/helix-core/src/movement.rs
+++ b/helix-core/src/movement.rs
@@ -177,6 +177,10 @@ pub fn move_prev_word_start(slice: RopeSlice, range: Range, count: usize) -> Ran
     word_move(slice, range, count, WordMotionTarget::PrevWordStart)
 }
 
+pub fn move_prev_word_end(slice: RopeSlice, range: Range, count: usize) -> Range {
+    word_move(slice, range, count, WordMotionTarget::PrevWordEnd)
+}
+
 pub fn move_next_long_word_start(slice: RopeSlice, range: Range, count: usize) -> Range {
     word_move(slice, range, count, WordMotionTarget::NextLongWordStart)
 }
@@ -189,8 +193,8 @@ pub fn move_prev_long_word_start(slice: RopeSlice, range: Range, count: usize) -
     word_move(slice, range, count, WordMotionTarget::PrevLongWordStart)
 }
 
-pub fn move_prev_word_end(slice: RopeSlice, range: Range, count: usize) -> Range {
-    word_move(slice, range, count, WordMotionTarget::PrevWordEnd)
+pub fn move_prev_long_word_end(slice: RopeSlice, range: Range, count: usize) -> Range {
+    word_move(slice, range, count, WordMotionTarget::PrevLongWordEnd)
 }
 
 fn word_move(slice: RopeSlice, range: Range, count: usize, target: WordMotionTarget) -> Range {
@@ -199,6 +203,7 @@ fn word_move(slice: RopeSlice, range: Range, count: usize, target: WordMotionTar
         WordMotionTarget::PrevWordStart
             | WordMotionTarget::PrevLongWordStart
             | WordMotionTarget::PrevWordEnd
+            | WordMotionTarget::PrevLongWordEnd
     );
 
     // Special-case early-out.
@@ -377,6 +382,7 @@ pub enum WordMotionTarget {
     NextLongWordStart,
     NextLongWordEnd,
     PrevLongWordStart,
+    PrevLongWordEnd,
 }
 
 pub trait CharHelpers {
@@ -393,6 +399,7 @@ impl CharHelpers for Chars<'_> {
             WordMotionTarget::PrevWordStart
                 | WordMotionTarget::PrevLongWordStart
                 | WordMotionTarget::PrevWordEnd
+                | WordMotionTarget::PrevLongWordEnd
         );
 
         // Reverse the iterator if needed for the motion direction.
@@ -479,7 +486,7 @@ fn reached_target(target: WordMotionTarget, prev_ch: char, next_ch: char) -> boo
             is_word_boundary(prev_ch, next_ch)
                 && (!prev_ch.is_whitespace() || char_is_line_ending(next_ch))
         }
-        WordMotionTarget::NextLongWordStart => {
+        WordMotionTarget::NextLongWordStart | WordMotionTarget::PrevLongWordEnd => {
             is_long_word_boundary(prev_ch, next_ch)
                 && (char_is_line_ending(next_ch) || !next_ch.is_whitespace())
         }
@@ -1446,6 +1453,100 @@ mod test {
     }
 
     #[test]
+    fn test_behaviour_when_moving_to_end_of_prev_long_words() {
+        let tests = [
+            (
+                "Basic backward motion from the middle of a word",
+                vec![(1, Range::new(3, 3), Range::new(4, 0))],
+            ),
+            ("Starting from after boundary retreats the anchor",
+                vec![(1, Range::new(0, 9), Range::new(8, 0))],
+            ),
+            (
+                "Jump    to end of a word succeeded by whitespace",
+                vec![(1, Range::new(10, 10), Range::new(10, 4))],
+            ),
+            (
+                "    Jump to start of line from end of word preceded by whitespace",
+                vec![(1, Range::new(3, 4), Range::new(4, 0))],
+            ),
+            ("Previous anchor is irrelevant for backward motions",
+                vec![(1, Range::new(12, 5), Range::new(6, 0))]),
+            (
+                "    Starting from whitespace moves to first space in sequence",
+                vec![(1, Range::new(0, 4), Range::new(4, 0))],
+            ),
+            ("Identifiers_with_underscores are considered a single word",
+                vec![(1, Range::new(0, 20), Range::new(20, 0))]),
+            (
+                "Jumping\n    \nback through a newline selects whitespace",
+                vec![(1, Range::new(0, 13), Range::new(12, 8))],
+            ),
+            (
+                "Jumping to start of word from the end selects the word",
+                vec![(1, Range::new(6, 7), Range::new(7, 0))],
+            ),
+            (
+                "alphanumeric.!,and.?=punctuation are treated exactly the same",
+                vec![(1, Range::new(29, 30), Range::new(30, 0))],
+            ),
+            (
+                "...   ... punctuation and spaces behave as expected",
+                vec![
+                    (1, Range::new(0, 10), Range::new(9, 3)),
+                    (1, Range::new(10, 6), Range::new(7, 3)),
+                ],
+            ),
+            (".._.._ punctuation is joined by underscores into a single block",
+                vec![(1, Range::new(0, 6), Range::new(6, 0))]),
+            (
+                "Newlines\n\nare bridged seamlessly.",
+                vec![(1, Range::new(0, 10), Range::new(8, 0))],
+            ),
+            (
+                "Jumping    \n\n\n\n\nback from within a newline group selects previous block",
+                vec![(1, Range::new(0, 13), Range::new(11, 7))],
+            ),
+            (
+                "Failed motions do not modify the range",
+                vec![(0, Range::new(3, 0), Range::new(3, 0))],
+            ),
+            (
+                "Multiple motions at once resolve correctly",
+                vec![(3, Range::new(19, 19), Range::new(8, 0))],
+            ),
+            (
+                "Excessive motions are performed partially",
+                vec![(999, Range::new(40, 40), Range::new(9, 0))],
+            ),
+            (
+                "", // Edge case of moving backwards in empty string
+                vec![(1, Range::new(0, 0), Range::new(0, 0))],
+            ),
+            (
+                "\n\n\n\n\n", // Edge case of moving backwards in all newlines
+                vec![(1, Range::new(5, 5), Range::new(0, 0))],
+            ),
+            ("   \n   \nJumping back through alternated space blocks and newlines selects the space blocks",
+                vec![
+                    (1, Range::new(0, 8), Range::new(7, 4)),
+                    (1, Range::new(7, 4), Range::new(3, 0)),
+                ]),
+            ("ヒーリ..クス multibyte characters behave as normal characters, including when interacting with punctuation",
+                vec![
+                    (1, Range::new(0, 8), Range::new(7, 0)),
+                ]),
+        ];
+
+        for (sample, scenario) in tests {
+            for (count, begin, expected_end) in scenario.into_iter() {
+                let range = move_prev_long_word_end(Rope::from(sample).slice(..), begin, count);
+                assert_eq!(range, expected_end, "Case failed: [{}]", sample);
+            }
+        }
+    }
+
+    #[test]
     fn test_behaviour_when_moving_to_prev_paragraph_single() {
         let tests = [
             ("#[|]#", "#[|]#"),