Merge pull request #75 from achristmascarl/cursor-word-end

add `CursorMove` for next end of word

src/cursor.rs

@@ -1,5 +1,5 @@
 use crate::widget::Viewport;
-use crate::word::{find_word_start_backward, find_word_start_forward};
+use crate::word::{find_word_end_next, find_word_start_backward, find_word_start_forward};
 #[cfg(feature = "arbitrary")]
 use arbitrary::Arbitrary;
 #[cfg(feature = "serde")]
@@ -121,6 +121,29 @@ pub enum CursorMove {
     /// assert_eq!(textarea.cursor(), (0, 8));
     /// ```
     WordForward,
+    /// Move cursor forward to the next end of word. Word boundary appears at spaces, punctuations, and others. For example
+    /// `fn foo(a)` consists of words `fn`, `foo`, `(`, `a`, `)`. When the cursor is at the end of line, it moves to the
+    /// end of the first word of the next line.
+    /// ```
+    /// use tui_textarea::{TextArea, CursorMove};
+    ///
+    /// let mut textarea = TextArea::from(["aaa bbb (c)", " dd"]);
+    ///
+    ///
+    /// textarea.move_cursor(CursorMove::WordEnd);
+    /// assert_eq!(textarea.cursor(), (0, 2));
+    /// textarea.move_cursor(CursorMove::WordEnd);
+    /// assert_eq!(textarea.cursor(), (0, 6));
+    /// textarea.move_cursor(CursorMove::WordEnd);
+    /// assert_eq!(textarea.cursor(), (0, 8));
+    /// textarea.move_cursor(CursorMove::WordEnd);
+    /// assert_eq!(textarea.cursor(), (0, 9));
+    /// textarea.move_cursor(CursorMove::WordEnd);
+    /// assert_eq!(textarea.cursor(), (0, 10));
+    /// textarea.move_cursor(CursorMove::WordEnd);
+    /// assert_eq!(textarea.cursor(), (1, 2));
+    /// ```
+    WordEnd,
     /// Move cursor backward by one word.  Word boundary appears at spaces, punctuations, and others. For example
     /// `fn foo(a)` consists of words `fn`, `foo`, `(`, `a`, `)`.When the cursor is at the head of line, it moves to
     /// the end of previous line.
@@ -263,6 +286,20 @@ impl CursorMove {
                 let row = lines.len() - 1;
                 Some((row, fit_col(col, &lines[row])))
             }
+            WordEnd => {
+                if let Some(col) = find_word_end_next(&lines[row], col) {
+                    Some((row, col))
+                } else if let Some(col) = (row + 1 < lines.len())
+                    .then(|| find_word_end_next(&lines[row + 1], 0))
+                    .unwrap_or_default()
+                {
+                    Some((row + 1, col))
+                } else if row + 1 < lines.len() {
+                    Some((row + 1, lines[row + 1].chars().count().saturating_sub(1)))
+                } else {
+                    Some((row, lines[row].chars().count().saturating_sub(1)))
+                }
+            }
             WordForward => {
                 if let Some(col) = find_word_start_forward(&lines[row], col) {
                     Some((row, col))

src/word.rs

@@ -43,6 +43,26 @@ pub fn find_word_end_forward(line: &str, start_col: usize) -> Option<usize> {
     None
 }
 
+pub fn find_word_end_next(line: &str, start_col: usize) -> Option<usize> {
+    let mut it = line.chars().enumerate().skip(start_col);
+    let (mut cur_col, cur_char) = it.next()?;
+    let mut cur = CharKind::new(cur_char);
+    for (next_col, c) in it {
+        let next = CharKind::new(c);
+        // if cursor started at the end of a word, don't stop
+        if next_col.saturating_sub(start_col) > 1 && cur != CharKind::Space && next != cur {
+            return Some(next_col.saturating_sub(1));
+        }
+        cur = next;
+        cur_col = next_col;
+    }
+    // if end of line is whitespace, don't stop the cursor
+    if cur != CharKind::Space && cur_col.saturating_sub(start_col) >= 1 {
+        return Some(cur_col);
+    }
+    None
+}
+
 pub fn find_word_start_backward(line: &str, start_col: usize) -> Option<usize> {
     let idx = line
         .char_indices()