Add command to merge consecutive ranges in selection (helix-editor#5047)

book/src/keymap.md

@@ -111,6 +111,7 @@
 | `s`                   | Select all regex matches inside selections                        | `select_regex`                       |
 | `S`                   | Split selection into subselections on regex matches               | `split_selection`                    |
 | `Alt-s`               | Split selection on newlines                                       | `split_selection_on_newline`         |
+| `Alt-_ `              | Merge consecutive selections                                      | `merge_consecutive_selections`       |
 | `&`                   | Align selection in columns                                        | `align_selections`                   |
 | `_`                   | Trim whitespace from the selection                                | `trim_selections`                    |
 | `;`                   | Collapse selection onto a single cursor                           | `collapse_selection`                 |

helix-core/src/selection.rs

@@ -495,28 +495,53 @@ impl Selection {
 
     /// Normalizes a `Selection`.
     fn normalize(mut self) -> Self {
-        let primary = self.ranges[self.primary_index];
+        let mut primary = self.ranges[self.primary_index];
         self.ranges.sort_unstable_by_key(Range::from);
+
+        self.ranges.dedup_by(|curr_range, prev_range| {
+            if prev_range.overlaps(curr_range) {
+                let new_range = curr_range.merge(*prev_range);
+                if prev_range == &primary || curr_range == &primary {
+                    primary = new_range;
+                }
+                *prev_range = new_range;
+                true
+            } else {
+                false
+            }
+        });
+
         self.primary_index = self
             .ranges
             .iter()
             .position(|&range| range == primary)
             .unwrap();
 
-        let mut prev_i = 0;
-        for i in 1..self.ranges.len() {
-            if self.ranges[prev_i].overlaps(&self.ranges[i]) {
-                self.ranges[prev_i] = self.ranges[prev_i].merge(self.ranges[i]);
+        self
+    }
+
+    // Merges all ranges that are consecutive
+    pub fn merge_consecutive_ranges(mut self) -> Self {
+        let mut primary = self.ranges[self.primary_index];
+
+        self.ranges.dedup_by(|curr_range, prev_range| {
+            if prev_range.to() == curr_range.from() {
+                let new_range = curr_range.merge(*prev_range);
+                if prev_range == &primary || curr_range == &primary {
+                    primary = new_range;
+                }
+                *prev_range = new_range;
+                true
             } else {
-                prev_i += 1;
-                self.ranges[prev_i] = self.ranges[i];
+                false
             }
-            if i == self.primary_index {
-                self.primary_index = prev_i;
-            }
-        }
+        });
 
-        self.ranges.truncate(prev_i + 1);
+        self.primary_index = self
+            .ranges
+            .iter()
+            .position(|&range| range == primary)
+            .unwrap();
 
         self
     }
@@ -1132,6 +1157,52 @@ mod test {
             &["", "abcd", "efg", "rs", "xyz"]
         );
     }
+
+    #[test]
+    fn test_merge_consecutive_ranges() {
+        let selection = Selection::new(
+            smallvec![
+                Range::new(0, 1),
+                Range::new(1, 10),
+                Range::new(15, 20),
+                Range::new(25, 26),
+                Range::new(26, 30)
+            ],
+            4,
+        );
+
+        let result = selection.merge_consecutive_ranges();
+
+        assert_eq!(
+            result.ranges(),
+            &[Range::new(0, 10), Range::new(15, 20), Range::new(25, 30)]
+        );
+        assert_eq!(result.primary_index, 2);
+
+        let selection = Selection::new(smallvec![Range::new(0, 1)], 0);
+        let result = selection.merge_consecutive_ranges();
+
+        assert_eq!(result.ranges(), &[Range::new(0, 1)]);
+        assert_eq!(result.primary_index, 0);
+
+        let selection = Selection::new(
+            smallvec![
+                Range::new(0, 1),
+                Range::new(1, 5),
+                Range::new(5, 8),
+                Range::new(8, 10),
+                Range::new(10, 15),
+                Range::new(18, 25)
+            ],
+            3,
+        );
+
+        let result = selection.merge_consecutive_ranges();
+
+        assert_eq!(result.ranges(), &[Range::new(0, 15), Range::new(18, 25)]);
+        assert_eq!(result.primary_index, 0);
+    }
+
     #[test]
     fn test_selection_contains() {
         fn contains(a: Vec<(usize, usize)>, b: Vec<(usize, usize)>) -> bool {

helix-term/src/commands.rs

@@ -244,6 +244,7 @@ impl MappableCommand {
         select_regex, "Select all regex matches inside selections",
         split_selection, "Split selections on regex matches",
         split_selection_on_newline, "Split selection on newlines",
+        merge_consecutive_selections, "Merge consecutive selections",
         search, "Search for regex pattern",
         rsearch, "Reverse search for regex pattern",
         search_next, "Select next search match",
@@ -1589,6 +1590,12 @@ fn split_selection_on_newline(cx: &mut Context) {
     doc.set_selection(view.id, selection);
 }
 
+fn merge_consecutive_selections(cx: &mut Context) {
+    let (view, doc) = current!(cx.editor);
+    let selection = doc.selection(view.id).clone().merge_consecutive_ranges();
+    doc.set_selection(view.id, selection);
+}
+
 #[allow(clippy::too_many_arguments)]
 fn search_impl(
     editor: &mut Editor,

helix-term/src/keymap/default.rs

@@ -76,6 +76,7 @@ pub fn default() -> HashMap<Mode, Keymap> {
 
         "s" => select_regex,
         "A-s" => split_selection_on_newline,
+        "A-_" => merge_consecutive_selections,
         "S" => split_selection,
         ";" => collapse_selection,
         "A-;" => flip_selections,