match pairs which don't form a standalone TS node

helix-core/src/match_brackets.rs

@@ -1,8 +1,13 @@
+use std::iter;
+
+use ropey::RopeSlice;
 use tree_sitter::Node;
 
-use crate::{Rope, Syntax};
+use crate::movement::Direction::{self, Backward, Forward};
+use crate::Syntax;
 
 const MAX_PLAINTEXT_SCAN: usize = 10000;
+const MATCH_LIMIT: usize = 16;
 
 // Limit matching pairs to only ( ) { } [ ] < > ' ' " "
 const PAIRS: &[(char, char)] = &[
@@ -24,7 +29,7 @@ const PAIRS: &[(char, char)] = &[
 ///
 /// If no matching bracket is found, `None` is returned.
 #[must_use]
-pub fn find_matching_bracket(syntax: &Syntax, doc: &Rope, pos: usize) -> Option<usize> {
+pub fn find_matching_bracket(syntax: &Syntax, doc: RopeSlice, pos: usize) -> Option<usize> {
     if pos >= doc.len_chars() || !is_valid_bracket(doc.char(pos)) {
         return None;
     }
@@ -42,35 +47,80 @@ pub fn find_matching_bracket(syntax: &Syntax, doc: &Rope, pos: usize) -> Option<
 //
 // If no surrounding scope is found, the function returns `None`.
 #[must_use]
-pub fn find_matching_bracket_fuzzy(syntax: &Syntax, doc: &Rope, pos: usize) -> Option<usize> {
+pub fn find_matching_bracket_fuzzy(syntax: &Syntax, doc: RopeSlice, pos: usize) -> Option<usize> {
     find_pair(syntax, doc, pos, true)
 }
 
-fn find_pair(syntax: &Syntax, doc: &Rope, pos: usize, traverse_parents: bool) -> Option<usize> {
+fn find_pair(
+    syntax: &Syntax,
+    doc: RopeSlice,
+    pos_: usize,
+    traverse_parents: bool,
+) -> Option<usize> {
     let tree = syntax.tree();
-    let pos = doc.char_to_byte(pos);
+    let pos = doc.char_to_byte(pos_);
 
-    let mut node = tree.root_node().named_descendant_for_byte_range(pos, pos)?;
+    let mut node = tree.root_node().descendant_for_byte_range(pos, pos)?;
 
     loop {
-        let (start_byte, end_byte) = surrounding_bytes(doc, &node)?;
-        let (start_char, end_char) = (doc.byte_to_char(start_byte), doc.byte_to_char(end_byte));
+        if node.is_named() {
+            let (start_byte, end_byte) = surrounding_bytes(doc, &node)?;
+            let (start_char, end_char) = (doc.byte_to_char(start_byte), doc.byte_to_char(end_byte));
+
+            if is_valid_pair(doc, start_char, end_char) {
+                if end_byte == pos {
+                    return Some(start_char);
+                }
+
+                // We return the end char if the cursor is either on the start char
+                // or at some arbitrary position between start and end char.
+                if traverse_parents || start_byte == pos {
+                    return Some(end_char);
+                }
+            }
+        }
+        // this node itselt wasn't a pair but maybe its siblings are
+
+        // check if we are *on* the pair (special cased so we don't look
+        // at the current node twice and to jump to the start on that case)
+        if let Some(open) = as_close_pair(doc, &node) {
+            if let Some(pair_start) = find_pair_end(doc, node.prev_sibling(), open, Backward) {
+                return Some(pair_start);
+            }
+        }
 
-        if is_valid_pair(doc, start_char, end_char) {
-            if end_byte == pos {
-                return Some(start_char);
+        if !traverse_parents {
+            // check if we are *on* the opening pair (special cased here as
+            // an opptimization since we only care about bracket on the cursor
+            // here)
+            if let Some(close) = as_open_pair(doc, &node) {
+                if let Some(pair_end) = find_pair_end(doc, node.next_sibling(), close, Forward) {
+                    return Some(pair_end);
+                }
+            }
+            if node.is_named() {
+                break;
             }
-            // We return the end char if the cursor is either on the start char
-            // or at some arbitrary position between start and end char.
-            return Some(end_char);
         }
 
-        if traverse_parents {
-            node = node.parent()?;
-        } else {
-            return None;
+        for close in
+            iter::successors(node.next_sibling(), |node| node.next_sibling()).take(MATCH_LIMIT)
+        {
+            let Some(open) = as_close_pair(doc, &close) else { continue; };
+            if find_pair_end(doc, Some(node), open, Backward).is_some() {
+                return doc.try_byte_to_char(close.start_byte()).ok();
+            }
         }
+        let Some(parent) = node.parent() else { break; };
+        node = parent;
     }
+    let node = tree.root_node().named_descendant_for_byte_range(pos, pos)?;
+    if node.child_count() != 0 {
+        return None;
+    }
+    let node_start = doc.byte_to_char(node.start_byte());
+    find_matching_bracket_plaintext(doc.byte_slice(node.byte_range()), pos_ - node_start)
+        .map(|pos| pos + node_start)
 }
 
 /// Returns the position of the matching bracket under cursor.
@@ -85,10 +135,7 @@ fn find_pair(syntax: &Syntax, doc: &Rope, pos: usize, traverse_parents: bool) ->
 ///
 /// If no matching bracket is found, `None` is returned.
 #[must_use]
-pub fn find_matching_bracket_current_line_plaintext(
-    doc: &Rope,
-    cursor_pos: usize,
-) -> Option<usize> {
+pub fn find_matching_bracket_plaintext(doc: RopeSlice, cursor_pos: usize) -> Option<usize> {
     // Don't do anything when the cursor is not on top of a bracket.
     let bracket = doc.char(cursor_pos);
     if !is_valid_bracket(bracket) {
@@ -144,11 +191,11 @@ fn is_forward_bracket(c: char) -> bool {
     PAIRS.iter().any(|(l, _)| *l == c)
 }
 
-fn is_valid_pair(doc: &Rope, start_char: usize, end_char: usize) -> bool {
+fn is_valid_pair(doc: RopeSlice, start_char: usize, end_char: usize) -> bool {
     PAIRS.contains(&(doc.char(start_char), doc.char(end_char)))
 }
 
-fn surrounding_bytes(doc: &Rope, node: &Node) -> Option<(usize, usize)> {
+fn surrounding_bytes(doc: RopeSlice, node: &Node) -> Option<(usize, usize)> {
     let len = doc.len_bytes();
 
     let start_byte = node.start_byte();
@@ -161,18 +208,67 @@ fn surrounding_bytes(doc: &Rope, node: &Node) -> Option<(usize, usize)> {
     Some((start_byte, end_byte))
 }
 
+/// Tests if this node is a pair close char and returns the expected open char
+fn as_close_pair(doc: RopeSlice, node: &Node) -> Option<char> {
+    let close = as_char(doc, node)?.1;
+    PAIRS
+        .iter()
+        .find_map(|&(open, close_)| (close_ == close).then_some(open))
+}
+
+/// Checks if `node` or its siblings (at most MATCH_LIMIT nodes) is the specified closing char
+///
+/// # Returns
+///
+/// The position of the found node or `None` otherwise
+fn find_pair_end(
+    doc: RopeSlice,
+    node: Option<Node>,
+    end_char: char,
+    direction: Direction,
+) -> Option<usize> {
+    let advance = match direction {
+        Forward => Node::next_sibling,
+        Backward => Node::prev_sibling,
+    };
+    iter::successors(node, advance)
+        .take(MATCH_LIMIT)
+        .find_map(|node| {
+            let (pos, c) = as_char(doc, &node)?;
+            (end_char == c).then_some(pos)
+        })
+}
+
+/// Tests if this node is a pair close char and returns the expected open char
+fn as_open_pair(doc: RopeSlice, node: &Node) -> Option<char> {
+    let open = as_char(doc, node)?.1;
+    PAIRS
+        .iter()
+        .find_map(|&(open_, close)| (open_ == open).then_some(close))
+}
+
+/// If node is a single char return it (and its char position)
+fn as_char(doc: RopeSlice, node: &Node) -> Option<(usize, char)> {
+    // TODO: multi char/non ASCII pairs
+    if node.byte_range().len() != 1 {
+        return None;
+    }
+    let pos = doc.try_byte_to_char(node.start_byte()).ok()?;
+    Some((pos, doc.char(pos)))
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
 
     #[test]
     fn test_find_matching_bracket_current_line_plaintext() {
         let assert = |input: &str, pos, expected| {
-            let input = &Rope::from(input);
-            let actual = find_matching_bracket_current_line_plaintext(input, pos);
+            let input = RopeSlice::from(input);
+            let actual = find_matching_bracket_plaintext(input, pos);
             assert_eq!(expected, actual.unwrap());
 
-            let actual = find_matching_bracket_current_line_plaintext(input, expected);
+            let actual = find_matching_bracket_plaintext(input, expected);
             assert_eq!(pos, actual.unwrap(), "expected symmetrical behaviour");
         };
 

helix-term/src/commands.rs

@@ -4535,8 +4535,8 @@ fn match_brackets(cx: &mut Context) {
     let selection = doc.selection(view.id).clone().transform(|range| {
         let pos = range.cursor(text_slice);
         if let Some(matched_pos) = doc.syntax().map_or_else(
-            || match_brackets::find_matching_bracket_current_line_plaintext(text, pos),
-            |syntax| match_brackets::find_matching_bracket_fuzzy(syntax, text, pos),
+            || match_brackets::find_matching_bracket_plaintext(text.slice(..), pos),
+            |syntax| match_brackets::find_matching_bracket_fuzzy(syntax, text.slice(..), pos),
         ) {
             range.put_cursor(text_slice, matched_pos, is_select)
         } else {

helix-term/src/ui/editor.rs

@@ -501,7 +501,9 @@ impl EditorView {
             use helix_core::match_brackets;
             let pos = doc.selection(view.id).primary().cursor(text);
 
-            if let Some(pos) = match_brackets::find_matching_bracket(syntax, doc.text(), pos) {
+            if let Some(pos) =
+                match_brackets::find_matching_bracket(syntax, doc.text().slice(..), pos)
+            {
                 // ensure col is on screen
                 if let Some(highlight) = theme.find_scope_index_exact("ui.cursor.match") {
                     return vec![(highlight, pos..pos + 1)];