fix: Normalize backtab into shift-tab

Fixes #1150

book/src/remapping.md

@@ -42,10 +42,9 @@ Control, Shift and Alt modifiers are encoded respectively with the prefixes
 | Down         | `"down"`       |
 | Home         | `"home"`       |
 | End          | `"end"`        |
-| Page         | `"pageup"`     |
-| Page         | `"pagedown"`   |
+| Page Up      | `"pageup"`     |
+| Page Down    | `"pagedown"`   |
 | Tab          | `"tab"`        |
-| Back         | `"backtab"`    |
 | Delete       | `"del"`        |
 | Insert       | `"ins"`        |
 | Null         | `"null"`       |

helix-term/src/ui/menu.rs

@@ -202,7 +202,7 @@ impl<T: Item + 'static> Component for Menu<T> {
                 return close_fn;
             }
             // arrow up/ctrl-p/shift-tab prev completion choice (including updating the doc)
-            shift!(BackTab) | key!(Up) | ctrl!('p') | ctrl!('k') => {
+            shift!(Tab) | key!(Up) | ctrl!('p') | ctrl!('k') => {
                 self.move_up();
                 (self.callback_fn)(cx.editor, self.selection(), MenuEvent::Update);
                 return EventResult::Consumed(None);

helix-term/src/ui/picker.rs

@@ -410,7 +410,7 @@ impl<T: 'static> Component for Picker<T> {
         })));
 
         match key_event.into() {
-            shift!(BackTab) | key!(Up) | ctrl!('p') | ctrl!('k') => {
+            shift!(Tab) | key!(Up) | ctrl!('p') | ctrl!('k') => {
                 self.move_up();
             }
             key!(Tab) | key!(Down) | ctrl!('n') | ctrl!('j') => {

helix-term/src/ui/prompt.rs

@@ -505,7 +505,7 @@ impl Component for Prompt {
                 self.change_completion_selection(CompletionDirection::Forward);
                 (self.callback_fn)(cx, &self.line, PromptEvent::Update)
             }
-            shift!(BackTab) => {
+            shift!(Tab) => {
                 self.change_completion_selection(CompletionDirection::Backward);
                 (self.callback_fn)(cx, &self.line, PromptEvent::Update)
             }

helix-view/src/input.rs

@@ -36,7 +36,6 @@ pub(crate) mod keys {
     pub(crate) const PAGEUP: &str = "pageup";
     pub(crate) const PAGEDOWN: &str = "pagedown";
     pub(crate) const TAB: &str = "tab";
-    pub(crate) const BACKTAB: &str = "backtab";
     pub(crate) const DELETE: &str = "del";
     pub(crate) const INSERT: &str = "ins";
     pub(crate) const NULL: &str = "null";
@@ -82,7 +81,6 @@ impl fmt::Display for KeyEvent {
             KeyCode::PageUp => f.write_str(keys::PAGEUP)?,
             KeyCode::PageDown => f.write_str(keys::PAGEDOWN)?,
             KeyCode::Tab => f.write_str(keys::TAB)?,
-            KeyCode::BackTab => f.write_str(keys::BACKTAB)?,
             KeyCode::Delete => f.write_str(keys::DELETE)?,
             KeyCode::Insert => f.write_str(keys::INSERT)?,
             KeyCode::Null => f.write_str(keys::NULL)?,
@@ -116,7 +114,6 @@ impl UnicodeWidthStr for KeyEvent {
             KeyCode::PageUp => keys::PAGEUP.len(),
             KeyCode::PageDown => keys::PAGEDOWN.len(),
             KeyCode::Tab => keys::TAB.len(),
-            KeyCode::BackTab => keys::BACKTAB.len(),
             KeyCode::Delete => keys::DELETE.len(),
             KeyCode::Insert => keys::INSERT.len(),
             KeyCode::Null => keys::NULL.len(),
@@ -166,7 +163,6 @@ impl std::str::FromStr for KeyEvent {
             keys::PAGEUP => KeyCode::PageUp,
             keys::PAGEDOWN => KeyCode::PageDown,
             keys::TAB => KeyCode::Tab,
-            keys::BACKTAB => KeyCode::BackTab,
             keys::DELETE => KeyCode::Delete,
             keys::INSERT => KeyCode::Insert,
             keys::NULL => KeyCode::Null,
@@ -220,14 +216,22 @@ impl<'de> Deserialize<'de> for KeyEvent {
 
 #[cfg(feature = "term")]
 impl From<crossterm::event::KeyEvent> for KeyEvent {
-    fn from(
-        crossterm::event::KeyEvent { code, modifiers }: crossterm::event::KeyEvent,
-    ) -> KeyEvent {
-        KeyEvent {
+    fn from(crossterm::event::KeyEvent { code, modifiers }: crossterm::event::KeyEvent) -> Self {
+        if code == crossterm::event::KeyCode::BackTab {
+            // special case for BackTab -> Shift-Tab
+            let mut modifiers: KeyModifiers = modifiers.into();
+            modifiers.insert(KeyModifiers::SHIFT);
+            Self {
+                code: KeyCode::Tab,
+                modifiers,
+            }
+        } else {
+            Self {
                 code: code.into(),
                 modifiers: modifiers.into(),
             }
         }
+    }
 }
 
 #[cfg(test)]

helix-view/src/keyboard.rs

@@ -79,8 +79,6 @@ pub enum KeyCode {
     PageDown,
     /// Tab key.
     Tab,
-    /// Shift + Tab key.
-    BackTab,
     /// Delete key.
     Delete,
     /// Insert key.
@@ -116,7 +114,6 @@ impl From<KeyCode> for crossterm::event::KeyCode {
             KeyCode::PageUp => CKeyCode::PageUp,
             KeyCode::PageDown => CKeyCode::PageDown,
             KeyCode::Tab => CKeyCode::Tab,
-            KeyCode::BackTab => CKeyCode::BackTab,
             KeyCode::Delete => CKeyCode::Delete,
             KeyCode::Insert => CKeyCode::Insert,
             KeyCode::F(f_number) => CKeyCode::F(f_number),
@@ -144,7 +141,7 @@ impl From<crossterm::event::KeyCode> for KeyCode {
             CKeyCode::PageUp => KeyCode::PageUp,
             CKeyCode::PageDown => KeyCode::PageDown,
             CKeyCode::Tab => KeyCode::Tab,
-            CKeyCode::BackTab => KeyCode::BackTab,
+            CKeyCode::BackTab => unreachable!("BackTab should have been handled on KeyEvent level"),
             CKeyCode::Delete => KeyCode::Delete,
             CKeyCode::Insert => KeyCode::Insert,
             CKeyCode::F(f_number) => KeyCode::F(f_number),