Remember the newline move mode on the range

helix-core/src/movement.rs

@@ -121,7 +121,13 @@ pub fn move_vertically_anchored(
     tab_width: usize,
 ) -> Range {
     let pos = range.cursor(slice);
-    let on_newline = pos == line_end_char_index(&slice, slice.char_to_line(pos));
+    let line = slice.char_to_line(pos);
+
+    // if we are resting on a newline character and we did not just move
+    // across an empty line where the newline_mode_mode flag was negativley
+    // carried we are in newline movement mode.
+    let newline_move_mode = pos == line_end_char_index(&slice, line)
+        && !(!range.newline_move_mode && slice.line(line).len_chars() == 1);
 
     // Compute the current position's 2d coordinates.
     let Position { row, col } = visual_coords_at_pos(slice, pos, tab_width);
@@ -135,11 +141,17 @@ pub fn move_vertically_anchored(
 
     // if we are already on a newline character, we want to navigate to the
     // newline character on the new line we moved to.
-    let new_pos = if on_newline {
-        let new_pos = pos_at_visual_coords(slice, Position::new(new_row, col), tab_width);
-        line_end_char_index(&slice, slice.char_to_line(new_pos))
+    let (new_pos, newline_move_mode) = if newline_move_mode {
+        let new_pos = line_end_char_index(
+            &slice,
+            slice.char_to_line(pos_at_visual_coords(
+                slice,
+                Position::new(new_row, col),
+                tab_width,
+            )),
+        );
 
-    // otherwise place us on the last character before the actual newline character.
+        (new_pos, true)
     } else {
         let new_col = col.max(horiz as usize);
         let mut new_pos = pos_at_visual_coords(slice, Position::new(new_row, new_col), tab_width);
@@ -150,15 +162,18 @@ pub fn move_vertically_anchored(
         }
 
         // Move away from the newline character.
-        let end_index = line_end_char_index(&slice, slice.char_to_line(new_pos));
-        if new_pos == end_index {
+        let end_index = line_end_char_index(&slice, new_row);
+        if new_pos == end_index && slice.line(new_row).len_chars() != 1 {
             new_pos = graphemes::prev_grapheme_boundary(slice, end_index);
         }
-        new_pos
+
+        // non newline movement mode carries the flag of the range forward
+        (new_pos, range.newline_move_mode)
     };
 
     let mut new_range = range.put_cursor(slice, new_pos, behaviour == Movement::Extend);
     new_range.horiz = Some(horiz);
+    new_range.newline_move_mode = newline_move_mode;
     new_range
 }
 

helix-core/src/selection.rs

@@ -53,7 +53,12 @@ pub struct Range {
     pub anchor: usize,
     /// The head of the range, moved when extending.
     pub head: usize,
+    /// Retains the information about the horizontal column we were on
     pub horiz: Option<u32>,
+    /// Disambiugation state for movement across empty lines for anchored
+    /// newline movement.  If this flag is `true` it means that we came
+    /// from the newline character rather than a character in the line.
+    pub newline_move_mode: bool,
 }
 
 impl Range {
@@ -62,6 +67,7 @@ impl Range {
             anchor,
             head,
             horiz: None,
+            newline_move_mode: false,
         }
     }
 
@@ -128,6 +134,7 @@ impl Range {
             anchor: self.head,
             head: self.anchor,
             horiz: self.horiz,
+            newline_move_mode: self.newline_move_mode,
         }
     }
 
@@ -186,6 +193,7 @@ impl Range {
             anchor,
             head,
             horiz: None,
+            newline_move_mode: false,
         }
     }
 
@@ -199,12 +207,14 @@ impl Range {
                 anchor: self.anchor.min(from),
                 head: self.head.max(to),
                 horiz: None,
+                newline_move_mode: false,
             }
         } else {
             Self {
                 anchor: self.anchor.max(to),
                 head: self.head.min(from),
                 horiz: None,
+                newline_move_mode: false,
             }
         }
     }
@@ -220,12 +230,14 @@ impl Range {
                 anchor: self.anchor.max(other.anchor),
                 head: self.head.min(other.head),
                 horiz: None,
+                newline_move_mode: false,
             }
         } else {
             Range {
                 anchor: self.from().min(other.from()),
                 head: self.to().max(other.to()),
                 horiz: None,
+                newline_move_mode: false,
             }
         }
     }
@@ -284,6 +296,11 @@ impl Range {
             } else {
                 None
             },
+            newline_move_mode: if new_anchor == self.anchor {
+                self.newline_move_mode
+            } else {
+                false
+            },
         }
     }
 
@@ -307,6 +324,7 @@ impl Range {
                 anchor: self.anchor,
                 head: next_grapheme_boundary(slice, self.head),
                 horiz: self.horiz,
+                newline_move_mode: self.newline_move_mode,
             }
         } else {
             *self
@@ -379,6 +397,7 @@ impl From<(usize, usize)> for Range {
             anchor,
             head,
             horiz: None,
+            newline_move_mode: false,
         }
     }
 }
@@ -482,7 +501,8 @@ impl Selection {
             ranges: smallvec![Range {
                 anchor,
                 head,
-                horiz: None
+                horiz: None,
+                newline_move_mode: false,
             }],
             primary_index: 0,
         }