refactor: move some things with their appropriate verticals

src/app/draw.rs

@@ -1,5 +1,26 @@
 use crate::*;
 
+/// The [Draw] implementation for [App] handles the loaded view,
+/// which is defined in terms of [dizzle] DSL.
+///
+/// If there is an error, the error is displayed. FIXME: overlay it
+/// Then, every top-level form of the DSL description is rendered.
+impl Draw<Tui> for App {
+    fn draw (self, to: &mut Tui) -> Usually<XYWH<u16>> {
+        let xywh = to.area().into();
+        if let Some(e) = self.error.read().unwrap().as_ref() {
+            to.show(xywh, e.as_ref())?;
+        }
+        for (index, dsl) in self.mode.view.iter().enumerate() {
+            if let Err(e) = self.interpret(to, dsl) {
+                *self.error.write().unwrap() = Some(format!("view #{index}: {e}").into());
+                break;
+            }
+        }
+        Ok(xywh)
+    }
+}
+
 impl Interpret<Tui, XYWH<u16>> for App {
     fn interpret_expr <'a> (&'a self, to: &mut Tui, lang: &'a impl Expression)
         -> Usually<XYWH<u16>>