feat: cycle command completions backward with Shift+Tab

src/editor.rs

@@ -810,6 +810,11 @@ core_actions![
         Action::CommandComplete,
         &[Mode::Command],
     ),
+    (
+        "core.command_complete_previous",
+        Action::CommandCompletePrevious,
+        &[Mode::Command],
+    ),
     (
         "core.palette",
         Action::Palette,
@@ -1589,10 +1594,15 @@ fn default_bindings() -> HashMap<Mode, HashMap<Input, Binding>> {
                 .insert(key, Binding::Action(action));
         }
     }
-    bindings
-        .entry(Mode::Command)
-        .or_default()
-        .insert(Input::Char('\t'), Binding::Action(CommandComplete));
+    for (key, action) in [
+        (Input::Char('\t'), CommandComplete),
+        (Input::BackTab, CommandCompletePrevious),
+    ] {
+        bindings
+            .entry(Mode::Command)
+            .or_default()
+            .insert(key, Binding::Action(action));
+    }
     for mode in [Mode::Command, Mode::Search] {
         for (key, action) in [(Input::Up, Up), (Input::Ctrl('k'), Up), (Input::Down, Down)] {
             bindings
@@ -8020,7 +8030,9 @@ impl Editor {
         let mode = self.binding_mode();
         if !matches!(
             self.bindings.get(&mode).and_then(|keys| keys.get(&input)),
-            Some(Binding::Action(Action::CommandComplete))
+            Some(Binding::Action(
+                Action::CommandComplete | Action::CommandCompletePrevious
+            ))
         ) {
             self.active.view.command_completion_prefix = None;
         }
@@ -8437,7 +8449,7 @@ impl Editor {
         self.active.view.mode = Mode::Command;
     }
 
-    fn complete_command(&mut self) {
+    fn complete_command(&mut self, forward: bool) {
         let view = &mut self.active.view;
         let command = view.command_line.trim_start();
         let name = command.strip_prefix(':').unwrap_or(command);
@@ -8449,6 +8461,9 @@ impl Editor {
         let prefix = view
             .command_completion_prefix
             .get_or_insert_with(|| name.to_owned());
+        let precedes = |left: &str, right: &str| {
+            if forward { left < right } else { left > right }
+        };
         let mut first = None;
         let mut next = None;
         for candidate in self.features.values().flat_map(|feature| &feature.commands) {
@@ -8456,10 +8471,13 @@ impl Editor {
             if !candidate.starts_with(prefix.as_str()) {
                 continue;
             }
-            if first.is_none_or(|first| candidate < first) {
+            if first.is_none_or(|first| precedes(candidate, first)) {
                 first = Some(candidate);
             }
-            if cycling && candidate > name && next.is_none_or(|next| candidate < next) {
+            if cycling
+                && precedes(name, candidate)
+                && next.is_none_or(|next| precedes(candidate, next))
+            {
                 next = Some(candidate);
             }
         }
@@ -8563,7 +8581,9 @@ impl Editor {
         let count = self.count.take().unwrap_or(1);
         self.clear_sequence();
         match action {
-            Action::CommandComplete => self.complete_command(),
+            Action::CommandComplete | Action::CommandCompletePrevious => {
+                self.complete_command(action == Action::CommandComplete);
+            }
             Action::SnippetNext => {
                 if self.snippet.is_some() {
                     self.navigate_snippet(true);