Reimplement tree motions in terms of syntax::TreeCursor

This uses the new TreeCursor type from the parent commit to reimplement
the tree-sitter motions (`A-p/o/i/n`). Other tree-sitter related
features like textobjects are not touched with this change and will
need a different, unrelated approach to solve.

2 files changed, 63 insertions, 8 deletions

diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index 291ab1fe..ff72cee1 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -26,7 +26,6 @@ use helix_core::{
     syntax::{BlockCommentToken, LanguageServerFeature},
     text_annotations::TextAnnotations,
     textobject,
-    tree_sitter::Node,
     unicode::width::UnicodeWidthChar,
     visual_offset_from_block, Deletion, LineEnding, Position, Range, Rope, RopeGraphemes,
     RopeReader, RopeSlice, Selection, SmallVec, Tendril, Transaction,
@@ -4775,18 +4774,17 @@ fn shrink_selection(cx: &mut Context) {
     cx.editor.apply_motion(motion);
 }
 
-fn select_sibling_impl<F>(cx: &mut Context, sibling_fn: &'static F)
+fn select_sibling_impl<F>(cx: &mut Context, sibling_fn: F)
 where
-    F: Fn(Node) -> Option<Node>,
+    F: Fn(&helix_core::Syntax, RopeSlice, Selection) -> Selection + 'static,
 {
-    let motion = |editor: &mut Editor| {
+    let motion = move |editor: &mut Editor| {
         let (view, doc) = current!(editor);
 
         if let Some(syntax) = doc.syntax() {
             let text = doc.text().slice(..);
             let current_selection = doc.selection(view.id);
-            let selection =
-                object::select_sibling(syntax, text, current_selection.clone(), sibling_fn);
+            let selection = sibling_fn(syntax, text, current_selection.clone());
             doc.set_selection(view.id, selection);
         }
     };
@@ -4794,11 +4792,11 @@ where
 }
 
 fn select_next_sibling(cx: &mut Context) {
-    select_sibling_impl(cx, &|node| Node::next_sibling(&node))
+    select_sibling_impl(cx, object::select_next_sibling)
 }
 
 fn select_prev_sibling(cx: &mut Context) {
-    select_sibling_impl(cx, &|node| Node::prev_sibling(&node))
+    select_sibling_impl(cx, object::select_prev_sibling)
 }
 
 fn move_node_bound_impl(cx: &mut Context, dir: Direction, movement: Movement) {
diff --git a/helix-term/tests/test/movement.rs b/helix-term/tests/test/movement.rs
index 4ebaae85..1c25032c 100644
--- a/helix-term/tests/test/movement.rs
+++ b/helix-term/tests/test/movement.rs
@@ -635,3 +635,60 @@ async fn test_surround_delete() -> anyhow::Result<()> {
 
     Ok(())
 }
+
+#[tokio::test(flavor = "multi_thread")]
+async fn tree_sitter_motions_work_across_injections() -> anyhow::Result<()> {
+    test_with_config(
+        AppBuilder::new().with_file("foo.html", None),
+        (
+            "<script>let #[|x]# = 1;</script>",
+            "<A-o>",
+            "<script>let #[|x = 1]#;</script>",
+        ),
+    )
+    .await?;
+
+    // When the full injected layer is selected, expand_selection jumps to
+    // a more shallow layer.
+    test_with_config(
+        AppBuilder::new().with_file("foo.html", None),
+        (
+            "<script>#[|let x = 1;]#</script>",
+            "<A-o>",
+            "#[|<script>let x = 1;</script>]#",
+        ),
+    )
+    .await?;
+
+    test_with_config(
+        AppBuilder::new().with_file("foo.html", None),
+        (
+            "<script>let #[|x = 1]#;</script>",
+            "<A-i>",
+            "<script>let #[|x]# = 1;</script>",
+        ),
+    )
+    .await?;
+
+    test_with_config(
+        AppBuilder::new().with_file("foo.html", None),
+        (
+            "<script>let #[|x]# = 1;</script>",
+            "<A-n>",
+            "<script>let x #[|=]# 1;</script>",
+        ),
+    )
+    .await?;
+
+    test_with_config(
+        AppBuilder::new().with_file("foo.html", None),
+        (
+            "<script>let #[|x]# = 1;</script>",
+            "<A-p>",
+            "<script>#[|let]# x = 1;</script>",
+        ),
+    )
+    .await?;
+
+    Ok(())
+}