From 9ebe2361a98fca58ca2e363419733b8ee790c49b Mon Sep 17 00:00:00 2001
From: Joscha <joscha@plugh.de>
Date: Sun, 7 Aug 2022 00:25:53 +0200
Subject: [PATCH] Move cursor one word left/right

---
 src/ui/util.rs           |  4 ++++
 src/ui/widgets/editor.rs | 44 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/src/ui/util.rs b/src/ui/util.rs
index 67e258f..402372f 100644
--- a/src/ui/util.rs
+++ b/src/ui/util.rs
@@ -54,6 +54,8 @@ pub fn list_editor_key_bindings(
     // Cursor movement
     bindings.binding("ctrl+b, ←", "move cursor left");
     bindings.binding("ctrl+f, →", "move cursor right");
+    bindings.binding("alt+b, ctrl+←", "move cursor left a word");
+    bindings.binding("alt+f, ctrl+→", "move cursor right a word");
     bindings.binding("ctrl+a, home", "move cursor to start of line");
     bindings.binding("ctrl+e, end", "move cursor to end of line");
     bindings.binding("↑/↓", "move cursor up/down");
@@ -86,6 +88,8 @@ pub fn handle_editor_key_event(
         // Cursor movement
         key!(Ctrl + 'b') | key!(Left) => editor.move_cursor_left(terminal.frame()),
         key!(Ctrl + 'f') | key!(Right) => editor.move_cursor_right(terminal.frame()),
+        key!(Alt + 'b') | key!(Ctrl + Left) => editor.move_cursor_left_a_word(terminal.frame()),
+        key!(Alt + 'f') | key!(Ctrl + Right) => editor.move_cursor_right_a_word(terminal.frame()),
         key!(Ctrl + 'a') | key!(Home) => editor.move_cursor_to_start_of_line(terminal.frame()),
         key!(Ctrl + 'e') | key!(End) => editor.move_cursor_to_end_of_line(terminal.frame()),
         key!(Up) => editor.move_cursor_up(terminal.frame()),
diff --git a/src/ui/widgets/editor.rs b/src/ui/widgets/editor.rs
index 20f4a38..cae62ca 100644
--- a/src/ui/widgets/editor.rs
+++ b/src/ui/widgets/editor.rs
@@ -237,6 +237,42 @@ impl InnerEditorState {
         }
     }
 
+    fn move_cursor_left_a_word(&mut self, frame: &mut Frame) {
+        let boundaries = self.grapheme_boundaries();
+        let mut encountered_word = false;
+        for (start, end) in boundaries.iter().zip(boundaries.iter().skip(1)).rev() {
+            if *end == self.idx {
+                let g = &self.text[*start..*end];
+                let whitespace = g.chars().all(|c| c.is_whitespace());
+                if encountered_word && whitespace {
+                    break;
+                } else if !whitespace {
+                    encountered_word = true;
+                }
+                self.idx = *start;
+            }
+        }
+        self.record_cursor_col(frame);
+    }
+
+    fn move_cursor_right_a_word(&mut self, frame: &mut Frame) {
+        let boundaries = self.grapheme_boundaries();
+        let mut encountered_word = false;
+        for (start, end) in boundaries.iter().zip(boundaries.iter().skip(1)) {
+            if *start == self.idx {
+                let g = &self.text[*start..*end];
+                let whitespace = g.chars().all(|c| c.is_whitespace());
+                if encountered_word && whitespace {
+                    break;
+                } else if !whitespace {
+                    encountered_word = true;
+                }
+                self.idx = *end;
+            }
+        }
+        self.record_cursor_col(frame);
+    }
+
     fn move_cursor_to_start_of_line(&mut self, frame: &mut Frame) {
         let boundaries = self.line_boundaries();
         let (line, _, _) = self.cursor_line(&boundaries);
@@ -329,6 +365,14 @@ impl EditorState {
         self.0.lock().move_cursor_right(frame);
     }
 
+    pub fn move_cursor_left_a_word(&self, frame: &mut Frame) {
+        self.0.lock().move_cursor_left_a_word(frame);
+    }
+
+    pub fn move_cursor_right_a_word(&self, frame: &mut Frame) {
+        self.0.lock().move_cursor_right_a_word(frame);
+    }
+
     pub fn move_cursor_to_start_of_line(&self, frame: &mut Frame) {
         self.0.lock().move_cursor_to_start_of_line(frame);
     }