Add 'Repeat last command' ('.')

Fixes #29

help.txt

@@ -101,6 +101,7 @@ Editing:
                   ( -> )
                   / -> \
 - ; : Go to prompt mode
+- . : Repeat the previous command
 
 
 # Insert

src/core/exec.rs

@@ -220,6 +220,14 @@ impl Editor {
             (Command(Normal), Char('~')) => {
                 self.invert_chars(n);
             }
+            (Command(Normal), Char('.')) => {
+                if let Some(inst) = self.previous_instruction {
+                    self.exec(inst);
+                } else {
+                    self.status_bar.msg = "No previous command".into();
+                    self.redraw_task = RedrawTask::StatusBar;
+                }
+            }
             (Command(Normal), Char(c)) => {
                 self.status_bar.msg = format!("Unknown command: {}", c);
                 self.redraw_task = RedrawTask::StatusBar;
@@ -249,5 +257,9 @@ impl Editor {
         if mov {
             self.redraw_task = RedrawTask::Cursor(bef, self.pos());
         }
+
+        if !(self.cursor().mode == Command(Normal) && cmd.key == Char('.')) {
+            self.previous_instruction = Some(Inst(para, cmd));
+        }
     }
 }

src/state/editor.rs

@@ -37,6 +37,8 @@ pub struct Editor {
     pub key_state: KeyState,
     /// Redraw
     pub redraw_task: RedrawTask,
+    /// The previous instruction
+    pub previous_instruction: Option<Inst>,
 }
 
 impl Editor {
@@ -59,6 +61,7 @@ impl Editor {
             options: Options::new(),
             key_state: KeyState::new(),
             redraw_task: RedrawTask::None,
+            previous_instruction: None,
         };
 
         #[cfg(not(feature = "orbital"))]
@@ -73,6 +76,7 @@ impl Editor {
             options: Options::new(),
             key_state: KeyState::new(),
             redraw_task: RedrawTask::None,
+            previous_instruction: None,
         };
 
         if let Some(x) = args().skip(1).next() {