Add multiline support

src/engine.rs

@@ -307,6 +307,95 @@ impl Reedline {
         self.line_buffer.clear();
     }
 
+    fn up_command(&mut self) {
+        // If we're at the top, then:
+        if !self.line_buffer.get_buffer()[0..self.line_buffer.insertion_point().offset]
+            .contains('\n')
+        {
+            // If we're at the top, move to previous history
+            self.previous_history();
+        } else {
+            // If we're not at the top, move up a line in the multiline buffer
+            let mut position = self.line_buffer.insertion_point().offset;
+            let mut num_of_move_lefts = 0;
+            let buffer = self.line_buffer.get_buffer().to_string();
+
+            // Move left until we're looking at the newline
+            // Observe what column we were on
+            while position > 0 && &buffer[(position - 1)..position] != "\n" {
+                self.line_buffer.move_left();
+                num_of_move_lefts += 1;
+                position = self.line_buffer.insertion_point().offset;
+            }
+
+            // Find start of previous line
+            let mut matches = buffer[0..(position - 1)].rmatch_indices('\n');
+
+            if let Some((pos, _)) = matches.next() {
+                position = pos + 1;
+            } else {
+                position = 0;
+            }
+            self.line_buffer.set_insertion_point(InsertionPoint {
+                line: 0,
+                offset: position,
+            });
+
+            // Move right from this position to the column we were at
+            while &buffer[position..(position + 1)] != "\n" && num_of_move_lefts > 0 {
+                self.line_buffer.move_right();
+                position = self.line_buffer.insertion_point().offset;
+                num_of_move_lefts -= 1;
+            }
+        }
+    }
+
+    fn down_command(&mut self) {
+        // If we're at the top, then:
+        if !self.line_buffer.get_buffer()[self.line_buffer.insertion_point().offset..]
+            .contains('\n')
+        {
+            // If we're at the top, move to previous history
+            self.next_history();
+        } else {
+            // If we're not at the top, move up a line in the multiline buffer
+            let mut position = self.line_buffer.insertion_point().offset;
+            let mut num_of_move_lefts = 0;
+            let buffer = self.line_buffer.get_buffer().to_string();
+
+            // Move left until we're looking at the newline
+            // Observe what column we were on
+            while position > 0 && &buffer[(position - 1)..position] != "\n" {
+                self.line_buffer.move_left();
+                num_of_move_lefts += 1;
+                position = self.line_buffer.insertion_point().offset;
+            }
+
+            // Find start of next line
+            let mut matches = buffer[position..].match_indices('\n');
+
+            // Assume this always succeeds
+
+            let (pos, _) = matches
+                .next()
+                .expect("internal error: should have found newline");
+
+            position += pos + 1;
+
+            self.line_buffer.set_insertion_point(InsertionPoint {
+                line: 0,
+                offset: position,
+            });
+
+            // Move right from this position to the column we were at
+            while &buffer[position..(position + 1)] != "\n" && num_of_move_lefts > 0 {
+                self.line_buffer.move_right();
+                position = self.line_buffer.insertion_point().offset;
+                num_of_move_lefts -= 1;
+            }
+        }
+    }
+
     fn append_to_history(&mut self) {
         self.history.append(self.insertion_line().to_string());
     }
@@ -485,6 +574,12 @@ impl Reedline {
                 EditCommand::NextHistory => {
                     self.next_history();
                 }
+                EditCommand::Up => {
+                    self.up_command();
+                }
+                EditCommand::Down => {
+                    self.down_command();
+                }
                 EditCommand::SearchHistory => {
                     self.search_history();
                 }

src/enums.rs

@@ -23,6 +23,8 @@ pub enum EditCommand {
     MoveRight,
     MoveWordLeft,
     MoveWordRight,
+    Up,
+    Down,
     InsertChar(char),
     Backspace,
     Delete,

src/keybindings.rs

@@ -179,6 +179,11 @@ pub fn default_emacs_keybindings() -> Keybindings {
         Char('t'),
         vec![EditCommand::SwapGraphemes],
     );
+    keybindings.add_binding(
+        KeyModifiers::ALT,
+        Enter,
+        vec![EditCommand::InsertChar('\n')],
+    );
     keybindings.add_binding(
         KeyModifiers::ALT,
         Char('b'),
@@ -227,8 +232,8 @@ pub fn default_emacs_keybindings() -> Keybindings {
     keybindings.add_binding(KeyModifiers::NONE, Delete, vec![EditCommand::Delete]);
     keybindings.add_binding(KeyModifiers::NONE, Home, vec![EditCommand::MoveToStart]);
     keybindings.add_binding(KeyModifiers::NONE, End, vec![EditCommand::MoveToEnd]);
-    keybindings.add_binding(KeyModifiers::NONE, Up, vec![EditCommand::PreviousHistory]);
-    keybindings.add_binding(KeyModifiers::NONE, Down, vec![EditCommand::NextHistory]);
+    keybindings.add_binding(KeyModifiers::NONE, Up, vec![EditCommand::Up]);
+    keybindings.add_binding(KeyModifiers::NONE, Down, vec![EditCommand::Down]);
     keybindings.add_binding(KeyModifiers::NONE, Left, vec![EditCommand::MoveLeft]);
     keybindings.add_binding(KeyModifiers::NONE, Right, vec![EditCommand::MoveRight]);
 

src/painter.rs

@@ -106,16 +106,38 @@ impl Painter {
             .highlight(&original_line)
             .render_around_insertion_point(cursor_position_in_buffer);
 
-        self.stdout
-            .queue(MoveTo(prompt_offset.0, prompt_offset.1))?
-            .queue(Print(highlighted_line.0))?
+        let (before_cursor, after_cursor) = highlighted_line;
+
+        let before_cursor_lines = before_cursor.lines();
+        let after_cursor_lines = after_cursor.lines();
+
+        let mut commands = self
+            .stdout
+            .queue(MoveTo(prompt_offset.0, prompt_offset.1))?;
+
+        for (idx, before_cursor_line) in before_cursor_lines.enumerate() {
+            if idx != 0 {
+                commands = commands.queue(Print("\r\n"))?;
+            }
+            commands = commands.queue(Print(before_cursor_line))?;
+        }
+
+        commands = commands
             .queue(SavePosition)?
             .queue(Print(self.hinter.handle(
                 &original_line,
                 cursor_position_in_buffer,
                 history,
-            )))?
-            .queue(Print(highlighted_line.1))?
+            )))?;
+
+        for (idx, after_cursor_line) in after_cursor_lines.enumerate() {
+            if idx != 0 {
+                commands = commands.queue(Print("\r\n"))?;
+            }
+            commands = commands.queue(Print(after_cursor_line))?;
+        }
+
+        commands
             .queue(Clear(ClearType::FromCursorDown))?
             .queue(RestorePosition)?
             .flush()?;