Add very basic cursor control

core/src/editor_buffer/mod.rs

@@ -13,12 +13,23 @@ pub struct EditorBuffer {
     filepath: Option<PathBuf>,
 }
 
-#[derive(Debug)]
+#[derive(Debug, PartialEq)]
 pub enum CommandResponse {
+    Ok,
     Success(String),
     Failure(String),
 }
 
+impl CommandResponse {
+    pub fn is_ok(&self) -> bool {
+        match self {
+            Self::Ok => true,
+            Self::Success(_) => true,
+            Self::Failure(_) => false
+        }
+    }
+}
+
 impl EditorBuffer {
     /// Create new empty [EditorBuffer]
     pub fn new() -> Self {
@@ -40,8 +51,13 @@ impl EditorBuffer {
         }
     }
 
-    fn move_cursor_to_point(&mut self, _point: Point) -> CommandResponse {
-        todo!()
+    pub fn get_cursor_position(&self) -> Point {
+        self.cursor
+    }
+
+    fn move_cursor_to_point(&mut self, point: Point) -> CommandResponse {
+        self.cursor = point;
+        CommandResponse::Ok
     }
 
     fn move_cursor_to_line_number(&mut self, _line_num: usize) -> CommandResponse {
@@ -107,4 +123,25 @@ mod tests {
         let found_contents: String = target.buffer.iter_chars().collect();
         assert_eq!(expected_contents, found_contents);
     }
+
+    #[test]
+    fn cursor_at_beginning_after_file_opened() {
+        let test_file = create_simple_test_file();
+        let mut target = EditorBuffer::new();
+        target.execute(Command::OpenFile(test_file.path().into()));
+        assert_eq!(Point::Start, target.get_cursor_position());
+    }
+
+    #[test]
+    fn move_cursor_to_point_in_file() {
+        let test_file = create_simple_test_file();
+        let mut target = EditorBuffer::new();
+        target.execute(Command::OpenFile(test_file.path().into()));
+        assert!(target.execute(Command::MoveCursorTo(Point::LineColumn(0, 5))).is_ok());
+        assert_eq!(Point::LineColumn(0,5), target.get_cursor_position());
+        assert!(target.execute(Command::MoveCursorTo(Point::LineColumn(3, 11))).is_ok());
+        assert_eq!(Point::LineColumn(3,11), target.get_cursor_position());
+        assert!(target.execute(Command::MoveCursorTo(Point::LineColumn(3, 0))).is_ok());
+        assert_eq!(Point::LineColumn(3,0), target.get_cursor_position());
+    }
 }

core/src/text_buffer/mod.rs

@@ -16,10 +16,12 @@ pub struct TextBuffer {
 }
 
 /// A location in a [TextBuffer]
-#[derive(Default, Clone, Copy)]
+#[derive(Clone, Copy, Debug, Default, PartialEq)]
 pub enum Point {
     /// The end of the buffer
     #[default]
+    Start,
+    LineColumn(usize, usize),
     End,
 }
 
@@ -63,6 +65,14 @@ impl TextBuffer {
     /// Insert `text` at `point`.
     pub fn insert_text(&mut self, text: impl Into<String>, point: Point) {
         match point {
+            Point::Start => {
+                self.contents = self
+                    .contents
+                    .insert_at_char_index(0, text);
+            },
+            Point::LineColumn(_, _) => {
+                todo!()
+            }
             Point::End => {
                 self.contents = self
                     .contents
@@ -73,6 +83,14 @@ impl TextBuffer {
 
     pub fn insert_char(&mut self, c: char, point: Point) {
         match point {
+            Point::Start => {
+                self.contents = self
+                    .contents
+                    .insert_at_char_index(0, c)
+            },
+            Point::LineColumn(_, _) => {
+                todo!()
+            }
             Point::End => {
                 self.contents = self
                     .contents