added append mode

src/main.rs

@@ -20,7 +20,7 @@ use std::io::{ stdin, stdout, Read, Stdout, Write };
 
 use crossterm::{
     cursor,
-    event::{Event, KeyCode, KeyEvent}
+    event::{ Event, KeyCode, KeyEvent, read },
     terminal,
     ExecutableCommand,
     Result
@@ -116,6 +116,7 @@ enum Mode {
     Normal,
     Command,
     Visual,
+    Append,
     Insert,
 }
 
@@ -125,6 +126,7 @@ impl Mode {
         match self {
             Mode::Normal => Style::SteadyBlock,
             Mode::Visual => Style::BlinkingBlock,
+            Mode::Append => Style::BlinkingBar,
             Mode::Insert => Style::BlinkingBar,
             Mode::Command => Style::SteadyUnderScore,
         }
@@ -174,6 +176,7 @@ impl State {
             Mode::Normal => self.on_normal_event(event),
             Mode::Command => self.on_command_event(event),
             Mode::Visual => self.on_visual_event(event),
+            Mode::Append => self.on_append_event(event),
             Mode::Insert => self.on_insert_event(event),
         }
     }
@@ -184,6 +187,10 @@ impl State {
                 KeyCode::Char('i') => {
                     self.mode = Mode::Insert;
                 }
+                KeyCode::Char('a') => {
+                    self.move_cursor(Direction::Right);
+                    self.mode = Mode::Append;
+                }
                 KeyCode::Char(':') => {
                     self.mode = Mode::Command;
                 }
@@ -223,6 +230,19 @@ impl State {
         }
     }
 
+    fn on_append_event(&mut self, event: Event) {
+        match event {
+            Event::Key(KeyEvent { code, .. }) => match code {
+                KeyCode::Esc => {
+                    self.move_cursor(Direction::Left);
+                    self.mode = Mode::Normal;
+                }
+            _ => self.on_insert_event(event),
+            },
+            _ => {}
+        }
+    }
+
     fn on_insert_event(&mut self, event: Event) {
         match event {
             Event::Key(KeyEvent { code, .. }) => match code {
@@ -274,7 +294,7 @@ impl State {
 fn screen_main(stdout: &mut Stdout, mut state: State) -> Result<()> {
     while !state.quit {
         state.draw(stdout)?;
-        let event = event::read()?;
+        let event = read()?;
         state.on_event(event);
     }