Macros (#1234)

* Macros WIP

`helix_term::compositor::Callback` changed to take a `&mut Context` as
a parameter for use by `play_macro`

* Default to `@` register for macros

* Import `KeyEvent`

* Special-case shift-tab -> backtab in `KeyEvent` conversion

* Move key recording to the compositor

* Add comment

* Add persistent display of macro recording status

When macro recording is active, the pending keys display will be shifted
3 characters left, and the register being recorded to will be displayed
between brackets — e.g., `[@]` — right of the pending keys display.

* Fix/add documentation

1 files changed, 7 insertions, 2 deletions

diff --git a/helix-term/src/compositor.rs b/helix-term/src/compositor.rs
index 30554ebb..321f56a5 100644
--- a/helix-term/src/compositor.rs
+++ b/helix-term/src/compositor.rs
@@ -7,7 +7,7 @@ use helix_view::graphics::{CursorKind, Rect};
 use crossterm::event::Event;
 use tui::buffer::Buffer as Surface;
 
-pub type Callback = Box<dyn FnOnce(&mut Compositor)>;
+pub type Callback = Box<dyn FnOnce(&mut Compositor, &mut Context)>;
 
 // --> EventResult should have a callback that takes a context with methods like .popup(),
 // .prompt() etc. That way we can abstract it from the renderer.
@@ -131,12 +131,17 @@ impl Compositor {
     }
 
     pub fn handle_event(&mut self, event: Event, cx: &mut Context) -> bool {
+        // If it is a key event and a macro is being recorded, push the key event to the recording.
+        if let (Event::Key(key), Some((_, keys))) = (event, &mut cx.editor.macro_recording) {
+            keys.push(key.into());
+        }
+
         // propagate events through the layers until we either find a layer that consumes it or we
         // run out of layers (event bubbling)
         for layer in self.layers.iter_mut().rev() {
             match layer.handle_event(event, cx) {
                 EventResult::Consumed(Some(callback)) => {
-                    callback(self);
+                    callback(self, cx);
                     return true;
                 }
                 EventResult::Consumed(None) => return true,