Automatically track pseudo-pending text (helix-editor#4077)

This change automatically tracks pending text for for commands which use
on-next-key callbacks. For example, `t` will await the next key event
and "t" will be shown in the bottom right-hand corner to show that we're
in a pending state.

Previously, the text for these on-next-key commands needed to be
hard-coded into the command definition which had some drawbacks:

* It was easy to forget to write and clear the pending text.
* If a command was remapped in a custom config, the pending text would
  still show the old key.

With this change, pending text is automatically tracked based on the
key events that lead to the command being executed. This works even
when the command is remapped in config and when the on-next-key
callback is nested under some key sequence (for example `mi`).

helix-term/src/commands.rs

@@ -1094,27 +1094,18 @@ fn extend_next_long_word_end(cx: &mut Context) {
     extend_word_impl(cx, movement::move_next_long_word_end)
 }
 
-fn will_find_char<F>(
-    cx: &mut Context,
-    search_fn: F,
-    inclusive: bool,
-    extend: bool,
-    pseudo_pending: &str,
-) where
+fn will_find_char<F>(cx: &mut Context, search_fn: F, inclusive: bool, extend: bool)
+where
     F: Fn(RopeSlice, char, usize, usize, bool) -> Option<usize> + 'static,
 {
     // TODO: count is reset to 1 before next key so we move it into the closure here.
     // Would be nice to carry over.
     let count = cx.count();
 
-    cx.editor.pseudo_pending = Some(pseudo_pending.to_string());
-
     // need to wait for next key
     // TODO: should this be done by grapheme rather than char?  For example,
     // we can't properly handle the line-ending CRLF case here in terms of char.
     cx.on_next_key(move |cx, event| {
-        cx.editor.pseudo_pending = None;
-
         let ch = match event {
             KeyEvent {
                 code: KeyCode::Enter,
@@ -1217,35 +1208,35 @@ fn find_prev_char_impl(
 }
 
 fn find_till_char(cx: &mut Context) {
-    will_find_char(cx, find_next_char_impl, false, false, "t")
+    will_find_char(cx, find_next_char_impl, false, false)
 }
 
 fn find_next_char(cx: &mut Context) {
-    will_find_char(cx, find_next_char_impl, true, false, "f")
+    will_find_char(cx, find_next_char_impl, true, false)
 }
 
 fn extend_till_char(cx: &mut Context) {
-    will_find_char(cx, find_next_char_impl, false, true, "t")
+    will_find_char(cx, find_next_char_impl, false, true)
 }
 
 fn extend_next_char(cx: &mut Context) {
-    will_find_char(cx, find_next_char_impl, true, true, "f")
+    will_find_char(cx, find_next_char_impl, true, true)
 }
 
 fn till_prev_char(cx: &mut Context) {
-    will_find_char(cx, find_prev_char_impl, false, false, "T")
+    will_find_char(cx, find_prev_char_impl, false, false)
 }
 
 fn find_prev_char(cx: &mut Context) {
-    will_find_char(cx, find_prev_char_impl, true, false, "F")
+    will_find_char(cx, find_prev_char_impl, true, false)
 }
 
 fn extend_till_prev_char(cx: &mut Context) {
-    will_find_char(cx, find_prev_char_impl, false, true, "T")
+    will_find_char(cx, find_prev_char_impl, false, true)
 }
 
 fn extend_prev_char(cx: &mut Context) {
-    will_find_char(cx, find_prev_char_impl, true, true, "F")
+    will_find_char(cx, find_prev_char_impl, true, true)
 }
 
 fn repeat_last_motion(cx: &mut Context) {
@@ -4432,7 +4423,6 @@ fn select_textobject(cx: &mut Context, objtype: textobject::TextObject) {
 
     cx.on_next_key(move |cx, event| {
         cx.editor.autoinfo = None;
-        cx.editor.pseudo_pending = None;
         if let Some(ch) = event.char() {
             let textobject = move |editor: &mut Editor| {
                 let (view, doc) = current!(editor);
@@ -4481,33 +4471,31 @@ fn select_textobject(cx: &mut Context, objtype: textobject::TextObject) {
         }
     });
 
-    if let Some((title, abbrev)) = match objtype {
-        textobject::TextObject::Inside => Some(("Match inside", "mi")),
-        textobject::TextObject::Around => Some(("Match around", "ma")),
+    let title = match objtype {
+        textobject::TextObject::Inside => "Match inside",
+        textobject::TextObject::Around => "Match around",
         _ => return,
-    } {
-        let help_text = [
-            ("w", "Word"),
-            ("W", "WORD"),
-            ("p", "Paragraph"),
-            ("c", "Class (tree-sitter)"),
-            ("f", "Function (tree-sitter)"),
-            ("a", "Argument/parameter (tree-sitter)"),
-            ("o", "Comment (tree-sitter)"),
-            ("t", "Test (tree-sitter)"),
-            ("m", "Closest surrounding pair to cursor"),
-            (" ", "... or any character acting as a pair"),
-        ];
-
-        cx.editor.autoinfo = Some(Info::new(
-            title,
-            help_text
-                .into_iter()
-                .map(|(col1, col2)| (col1.to_string(), col2.to_string()))
-                .collect(),
-        ));
-        cx.editor.pseudo_pending = Some(abbrev.to_string());
     };
+    let help_text = [
+        ("w", "Word"),
+        ("W", "WORD"),
+        ("p", "Paragraph"),
+        ("c", "Class (tree-sitter)"),
+        ("f", "Function (tree-sitter)"),
+        ("a", "Argument/parameter (tree-sitter)"),
+        ("o", "Comment (tree-sitter)"),
+        ("t", "Test (tree-sitter)"),
+        ("m", "Closest surrounding pair to cursor"),
+        (" ", "... or any character acting as a pair"),
+    ];
+
+    cx.editor.autoinfo = Some(Info::new(
+        title,
+        help_text
+            .into_iter()
+            .map(|(col1, col2)| (col1.to_string(), col2.to_string()))
+            .collect(),
+    ));
 }
 
 fn surround_add(cx: &mut Context) {

helix-term/src/ui/editor.rs

@@ -33,6 +33,7 @@ use super::statusline;
 pub struct EditorView {
     pub keymaps: Keymaps,
     on_next_key: Option<Box<dyn FnOnce(&mut commands::Context, KeyEvent)>>,
+    pseudo_pending: Vec<KeyEvent>,
     last_insert: (commands::MappableCommand, Vec<InsertEvent>),
     pub(crate) completion: Option<Completion>,
     spinners: ProgressSpinners,
@@ -57,6 +58,7 @@ impl EditorView {
         Self {
             keymaps,
             on_next_key: None,
+            pseudo_pending: Vec::new(),
             last_insert: (commands::MappableCommand::normal_mode, Vec::new()),
             completion: None,
             spinners: ProgressSpinners::default(),
@@ -841,6 +843,7 @@ impl EditorView {
         event: KeyEvent,
     ) -> Option<KeymapResult> {
         let mut last_mode = mode;
+        self.pseudo_pending.extend(self.keymaps.pending());
         let key_result = self.keymaps.get(mode, event);
         cxt.editor.autoinfo = self.keymaps.sticky().map(|node| node.infobox());
 
@@ -1323,6 +1326,11 @@ impl Component for EditorView {
                 }
 
                 self.on_next_key = cx.on_next_key_callback.take();
+                match self.on_next_key {
+                    Some(_) => self.pseudo_pending.push(key),
+                    None => self.pseudo_pending.clear(),
+                }
+
                 // appease borrowck
                 let callback = cx.callback.take();
 
@@ -1433,8 +1441,8 @@ impl Component for EditorView {
             for key in self.keymaps.pending() {
                 disp.push_str(&key.key_sequence_format());
             }
-            if let Some(pseudo_pending) = &cx.editor.pseudo_pending {
-                disp.push_str(pseudo_pending.as_str())
+            for key in &self.pseudo_pending {
+                disp.push_str(&key.key_sequence_format());
             }
             let style = cx.editor.theme.get("ui.text");
             let macro_width = if cx.editor.macro_recording.is_some() {

helix-view/src/editor.rs

@@ -743,7 +743,6 @@ pub struct Editor {
 
     pub idle_timer: Pin<Box<Sleep>>,
     pub last_motion: Option<Motion>,
-    pub pseudo_pending: Option<String>,
 
     pub last_completion: Option<CompleteAction>,
 
@@ -824,7 +823,6 @@ impl Editor {
             idle_timer: Box::pin(sleep(conf.idle_timeout)),
             last_motion: None,
             last_completion: None,
-            pseudo_pending: None,
             config,
             auto_pairs,
             exit_code: 0,