Keybind for Extend/shrink selection up and down

helix-term/src/commands.rs

@@ -61,6 +61,7 @@ use crate::{
 use crate::job::{self, Jobs};
 use futures_util::{stream::FuturesUnordered, TryStreamExt};
 use std::{
+    cmp::Ordering,
     collections::{HashMap, HashSet},
     fmt,
     future::Future,
@@ -298,6 +299,8 @@ impl MappableCommand {
         extend_line, "Select current line, if already selected, extend to another line based on the anchor",
         extend_line_below, "Select current line, if already selected, extend to next line",
         extend_line_above, "Select current line, if already selected, extend to previous line",
+        select_line_above, "Select current line, if already selected, extend or shrink line above based on the anchor",
+        select_line_below, "Select current line, if already selected, extend or shrink line below based on the anchor",
         extend_to_line_bounds, "Extend selection to line bounds",
         shrink_to_line_bounds, "Shrink selection to line bounds",
         delete_selection, "Delete selection",
@@ -2392,6 +2395,7 @@ fn global_search(cx: &mut Context) {
     );
 }
 
+#[derive(Clone, Copy)]
 enum Extend {
     Above,
     Below,
@@ -2413,7 +2417,66 @@ fn extend_line_below(cx: &mut Context) {
 fn extend_line_above(cx: &mut Context) {
     extend_line_impl(cx, Extend::Above);
 }
+fn select_line_below(cx: &mut Context) {
+    select_line_impl(cx, Extend::Below);
+}
+fn select_line_above(cx: &mut Context) {
+    select_line_impl(cx, Extend::Above);
+}
+fn select_line_impl(cx: &mut Context, extend: Extend) {
+    let mut count = cx.count();
+    let (view, doc) = current!(cx.editor);
 
+    let text = doc.text();
+    let selection = doc.selection(view.id).clone().transform(|range| {
+        let (start_line, end_line) = range.line_range(text.slice(..));
+        let start = text.line_to_char(start_line);
+        let end = text.line_to_char(
+            (end_line + 1) // newline of end_line
+                .min(text.len_lines()),
+        );
+        let direction = range.direction();
+
+        // Extending to line bounds is counted as one step
+        if range.from() != start || range.to() != end {
+            count = count.saturating_sub(1)
+        }
+        let (anchor_line, head_line) = match (extend, direction) {
+            (Extend::Above, Direction::Forward) => (start_line, end_line.saturating_sub(count)),
+            (Extend::Above, Direction::Backward) => (end_line, start_line.saturating_sub(count)),
+            (Extend::Below, Direction::Forward) => {
+                (start_line, (end_line + count).min(text.len_lines()))
+            }
+            (Extend::Below, Direction::Backward) => {
+                (end_line, (start_line + count).min(text.len_lines()))
+            }
+        };
+        let (anchor, head) = match anchor_line.cmp(&head_line) {
+            Ordering::Less => (
+                text.line_to_char(anchor_line),
+                text.line_to_char((head_line + 1).min(text.len_lines())),
+            ),
+            Ordering::Equal => match extend {
+                Extend::Above => (
+                    text.line_to_char((anchor_line + 1).min(text.len_lines())),
+                    text.line_to_char(head_line),
+                ),
+                Extend::Below => (
+                    text.line_to_char(head_line),
+                    text.line_to_char((anchor_line + 1).min(text.len_lines())),
+                ),
+            },
+
+            Ordering::Greater => (
+                text.line_to_char((anchor_line + 1).min(text.len_lines())),
+                text.line_to_char(head_line),
+            ),
+        };
+        Range::new(anchor, head)
+    });
+
+    doc.set_selection(view.id, selection);
+}
 fn extend_line_impl(cx: &mut Context, extend: Extend) {
     let count = cx.count();
     let (view, doc) = current!(cx.editor);