add redraw command (helix-editor#4354)

* add redraw command

* update docs

* Update helix-term/src/commands/typed.rs

Co-authored-by: Michael Davis <mcarsondavis@gmail.com>

* update docs

Co-authored-by: Michael Davis <mcarsondavis@gmail.com>

book/src/generated/typable-cmd.md

@@ -73,3 +73,4 @@
 | `:pipe` | Pipe each selection to the shell command. |
 | `:pipe-to` | Pipe each selection to the shell command, ignoring output. |
 | `:run-shell-command`, `:sh` | Run a shell command |
+| `:redraw` | Clear and re-render the whole UI |

helix-term/src/commands/typed.rs

@@ -1808,6 +1808,28 @@ fn run_shell_command(
     Ok(())
 }
 
+fn redraw(
+    cx: &mut compositor::Context,
+    _args: &[Cow<str>],
+    event: PromptEvent,
+) -> anyhow::Result<()> {
+    if event != PromptEvent::Validate {
+        return Ok(());
+    }
+
+    let callback = Box::pin(async move {
+        let call: job::Callback = Box::new(|_editor, compositor| {
+            compositor.clear().expect("unable to redraw");
+        });
+
+        Ok(call)
+    });
+
+    cx.jobs.callback(callback);
+
+    Ok(())
+}
+
 pub const TYPABLE_COMMAND_LIST: &[TypableCommand] = &[
         TypableCommand {
             name: "quit",
@@ -2323,6 +2345,13 @@ pub const TYPABLE_COMMAND_LIST: &[TypableCommand] = &[
             fun: run_shell_command,
             completer: Some(completers::directory),
         },
+        TypableCommand {
+            name: "redraw",
+            aliases: &[],
+            doc: "Clear and re-render the whole UI",
+            fun: redraw,
+            completer: None,
+        },
     ];
 
 pub static TYPABLE_COMMAND_MAP: Lazy<HashMap<&'static str, &'static TypableCommand>> =

helix-term/src/compositor.rs

@@ -197,6 +197,10 @@ impl Compositor {
             .find(|component| component.id() == Some(id))
             .and_then(|component| component.as_any_mut().downcast_mut())
     }
+
+    pub fn clear(&mut self) -> std::io::Result<()> {
+        self.terminal.clear()
+    }
 }
 
 // View casting, taken straight from Cursive