feat: find closest pair using tree-sitter

helix-core/src/match_brackets.rs

@@ -9,16 +9,32 @@ use crate::Syntax;
 const MAX_PLAINTEXT_SCAN: usize = 10000;
 const MATCH_LIMIT: usize = 16;
 
-// Limit matching pairs to only ( ) { } [ ] < > ' ' " "
-const PAIRS: &[(char, char)] = &[
+pub const BRACKETS: [(char, char); 7] = [
     ('(', ')'),
     ('{', '}'),
     ('[', ']'),
     ('<', '>'),
-    ('\'', '\''),
-    ('\"', '\"'),
+    ('«', '»'),
+    ('「', '」'),
+    ('（', '）'),
 ];
 
+// The difference between BRACKETS and PAIRS is that we can find matching
+// BRACKETS in a plain text file, but we can't do the same for PAIRs.
+// PAIRS also contains all BRACKETS.
+pub const PAIRS: [(char, char); BRACKETS.len() + 3] = {
+    let mut pairs = [(' ', ' '); BRACKETS.len() + 3];
+    let mut idx = 0;
+    while idx < BRACKETS.len() {
+        pairs[idx] = BRACKETS[idx];
+        idx += 1;
+    }
+    pairs[idx] = ('"', '"');
+    pairs[idx + 1] = ('\'', '\'');
+    pairs[idx + 2] = ('`', '`');
+    pairs
+};
+
 /// Returns the position of the matching bracket under cursor.
 ///
 /// If the cursor is on the opening bracket, the position of
@@ -30,7 +46,7 @@ const PAIRS: &[(char, char)] = &[
 /// If no matching bracket is found, `None` is returned.
 #[must_use]
 pub fn find_matching_bracket(syntax: &Syntax, doc: RopeSlice, pos: usize) -> Option<usize> {
-    if pos >= doc.len_chars() || !is_valid_bracket(doc.char(pos)) {
+    if pos >= doc.len_chars() || !is_valid_pair(doc.char(pos)) {
         return None;
     }
     find_pair(syntax, doc, pos, false)
@@ -67,7 +83,7 @@ fn find_pair(
             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 is_valid_pair_on_pos(doc, start_char, end_char) {
                 if end_byte == pos {
                     return Some(start_char);
                 }
@@ -140,14 +156,22 @@ fn find_pair(
 /// If no matching bracket is found, `None` is returned.
 #[must_use]
 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.get_char(cursor_pos)?;
+    let matching_bracket = {
+        let pair = get_pair(bracket);
+        if pair.0 == bracket {
+            pair.1
+        } else {
+            pair.0
+        }
+    };
+    // Don't do anything when the cursor is not on top of a bracket.
     if !is_valid_bracket(bracket) {
         return None;
     }
 
     // Determine the direction of the matching.
-    let is_fwd = is_forward_bracket(bracket);
+    let is_fwd = is_open_bracket(bracket);
     let chars_iter = if is_fwd {
         doc.chars_at(cursor_pos + 1)
     } else {
@@ -159,19 +183,7 @@ pub fn find_matching_bracket_plaintext(doc: RopeSlice, cursor_pos: usize) -> Opt
     for (i, candidate) in chars_iter.take(MAX_PLAINTEXT_SCAN).enumerate() {
         if candidate == bracket {
             open_cnt += 1;
-        } else if is_valid_pair(
-            doc,
-            if is_fwd {
-                cursor_pos
-            } else {
-                cursor_pos - i - 1
-            },
-            if is_fwd {
-                cursor_pos + i + 1
-            } else {
-                cursor_pos
-            },
-        ) {
+        } else if candidate == matching_bracket {
             // Return when all pending brackets have been closed.
             if open_cnt == 1 {
                 return Some(if is_fwd {
@@ -187,15 +199,49 @@ pub fn find_matching_bracket_plaintext(doc: RopeSlice, cursor_pos: usize) -> Opt
     None
 }
 
-fn is_valid_bracket(c: char) -> bool {
-    PAIRS.iter().any(|(l, r)| *l == c || *r == c)
+/// Returns the open and closing chars pair. If not found in
+/// [`BRACKETS`] returns (ch, ch).
+///
+/// ```
+/// use helix_core::match_brackets::get_pair;
+///
+/// assert_eq!(get_pair('['), ('[', ']'));
+/// assert_eq!(get_pair('}'), ('{', '}'));
+/// assert_eq!(get_pair('"'), ('"', '"'));
+/// ```
+pub fn get_pair(ch: char) -> (char, char) {
+    PAIRS
+        .iter()
+        .find(|(open, close)| *open == ch || *close == ch)
+        .copied()
+        .unwrap_or((ch, ch))
+}
+
+pub fn is_open_bracket(ch: char) -> bool {
+    BRACKETS.iter().any(|(l, _)| *l == ch)
+}
+
+pub fn is_close_bracket(ch: char) -> bool {
+    BRACKETS.iter().any(|(_, r)| *r == ch)
+}
+
+pub fn is_valid_bracket(ch: char) -> bool {
+    BRACKETS.iter().any(|(l, r)| *l == ch || *r == ch)
+}
+
+pub fn is_open_pair(ch: char) -> bool {
+    PAIRS.iter().any(|(l, _)| *l == ch)
+}
+
+pub fn is_close_pair(ch: char) -> bool {
+    PAIRS.iter().any(|(_, r)| *r == ch)
 }
 
-fn is_forward_bracket(c: char) -> bool {
-    PAIRS.iter().any(|(l, _)| *l == c)
+pub fn is_valid_pair(ch: char) -> bool {
+    PAIRS.iter().any(|(l, r)| *l == ch || *r == ch)
 }
 
-fn is_valid_pair(doc: RopeSlice, start_char: usize, end_char: usize) -> bool {
+fn is_valid_pair_on_pos(doc: RopeSlice, start_char: usize, end_char: usize) -> bool {
     PAIRS.contains(&(doc.char(start_char), doc.char(end_char)))
 }
 

helix-core/src/selection.rs

@@ -122,7 +122,7 @@ impl Range {
     }
 
     /// `Direction::Backward` when head < anchor.
-    /// `Direction::Backward` otherwise.
+    /// `Direction::Forward` otherwise.
     #[inline]
     #[must_use]
     pub fn direction(&self) -> Direction {

helix-core/src/surround.rs

@@ -1,18 +1,16 @@
 use std::fmt::Display;
 
-use crate::{movement::Direction, search, Range, Selection};
+use crate::{
+    graphemes::next_grapheme_boundary,
+    match_brackets::{
+        find_matching_bracket, find_matching_bracket_fuzzy, get_pair, is_close_bracket,
+        is_open_bracket,
+    },
+    movement::Direction,
+    search, Range, Selection, Syntax,
+};
 use ropey::RopeSlice;
 
-pub const PAIRS: &[(char, char)] = &[
-    ('(', ')'),
-    ('[', ']'),
-    ('{', '}'),
-    ('<', '>'),
-    ('«', '»'),
-    ('「', '」'),
-    ('（', '）'),
-];
-
 #[derive(Debug, PartialEq, Eq)]
 pub enum Error {
     PairNotFound,
@@ -34,32 +32,68 @@ impl Display for Error {
 
 type Result<T> = std::result::Result<T, Error>;
 
-/// Given any char in [PAIRS], return the open and closing chars. If not found in
-/// [PAIRS] return (ch, ch).
+/// Finds the position of surround pairs of any [`crate::match_brackets::PAIRS`]
+/// using tree-sitter when possible.
 ///
-/// ```
-/// use helix_core::surround::get_pair;
+/// # Returns
 ///
-/// assert_eq!(get_pair('['), ('[', ']'));
-/// assert_eq!(get_pair('}'), ('{', '}'));
-/// assert_eq!(get_pair('"'), ('"', '"'));
-/// ```
-pub fn get_pair(ch: char) -> (char, char) {
-    PAIRS
-        .iter()
-        .find(|(open, close)| *open == ch || *close == ch)
-        .copied()
-        .unwrap_or((ch, ch))
+/// Tuple `(anchor, head)`, meaning it is not always ordered.
+pub fn find_nth_closest_pairs_pos(
+    syntax: Option<&Syntax>,
+    text: RopeSlice,
+    range: Range,
+    skip: usize,
+) -> Result<(usize, usize)> {
+    match syntax {
+        Some(syntax) => find_nth_closest_pairs_ts(syntax, text, range, skip),
+        None => find_nth_closest_pairs_plain(text, range, skip),
+    }
 }
 
-pub fn find_nth_closest_pairs_pos(
+fn find_nth_closest_pairs_ts(
+    syntax: &Syntax,
     text: RopeSlice,
     range: Range,
     mut skip: usize,
 ) -> Result<(usize, usize)> {
-    let is_open_pair = |ch| PAIRS.iter().any(|(open, _)| *open == ch);
-    let is_close_pair = |ch| PAIRS.iter().any(|(_, close)| *close == ch);
+    let mut opening = range.from();
+    // We want to expand the selection if we are already on the found pair,
+    // otherwise we would need to subtract "-1" from "range.to()".
+    let mut closing = range.to();
+
+    while skip > 0 {
+        closing = find_matching_bracket_fuzzy(syntax, text, closing).ok_or(Error::PairNotFound)?;
+        opening = find_matching_bracket(syntax, text, closing).ok_or(Error::PairNotFound)?;
+        // If we're already on a closing bracket "find_matching_bracket_fuzzy" will return
+        // the position of the opening bracket.
+        if closing < opening {
+            (opening, closing) = (closing, opening);
+        }
+
+        // In case found brackets are partially inside current selection.
+        if range.from() < opening || closing < range.to() - 1 {
+            closing = next_grapheme_boundary(text, closing);
+        } else {
+            skip -= 1;
+            if skip != 0 {
+                closing = next_grapheme_boundary(text, closing);
+            }
+        }
+    }
+
+    // Keep the original direction.
+    if let Direction::Forward = range.direction() {
+        Ok((opening, closing))
+    } else {
+        Ok((closing, opening))
+    }
+}
 
+fn find_nth_closest_pairs_plain(
+    text: RopeSlice,
+    range: Range,
+    mut skip: usize,
+) -> Result<(usize, usize)> {
     let mut stack = Vec::with_capacity(2);
     let pos = range.from();
     let mut close_pos = pos.saturating_sub(1);
@@ -67,7 +101,7 @@ pub fn find_nth_closest_pairs_pos(
     for ch in text.chars_at(pos) {
         close_pos += 1;
 
-        if is_open_pair(ch) {
+        if is_open_bracket(ch) {
             // Track open pairs encountered so that we can step over
             // the corresponding close pairs that will come up further
             // down the loop. We want to find a lone close pair whose
@@ -76,7 +110,7 @@ pub fn find_nth_closest_pairs_pos(
             continue;
         }
 
-        if !is_close_pair(ch) {
+        if !is_close_bracket(ch) {
             // We don't care if this character isn't a brace pair item,
             // so short circuit here.
             continue;
@@ -157,7 +191,11 @@ pub fn find_nth_pairs_pos(
         )
     };
 
-    Option::zip(open, close).ok_or(Error::PairNotFound)
+    // preserve original direction
+    match range.direction() {
+        Direction::Forward => Option::zip(open, close).ok_or(Error::PairNotFound),
+        Direction::Backward => Option::zip(close, open).ok_or(Error::PairNotFound),
+    }
 }
 
 fn find_nth_open_pair(
@@ -249,6 +287,7 @@ fn find_nth_close_pair(
 /// are automatically detected around each cursor (note that this may result
 /// in them selecting different surround characters for each selection).
 pub fn get_surround_pos(
+    syntax: Option<&Syntax>,
     text: RopeSlice,
     selection: &Selection,
     ch: Option<char>,
@@ -257,9 +296,13 @@ pub fn get_surround_pos(
     let mut change_pos = Vec::new();
 
     for &range in selection {
-        let (open_pos, close_pos) = match ch {
-            Some(ch) => find_nth_pairs_pos(text, ch, range, skip)?,
-            None => find_nth_closest_pairs_pos(text, range, skip)?,
+        let (open_pos, close_pos) = {
+            let range_raw = match ch {
+                Some(ch) => find_nth_pairs_pos(text, ch, range, skip)?,
+                None => find_nth_closest_pairs_pos(syntax, text, range, skip)?,
+            };
+            let range = Range::new(range_raw.0, range_raw.1);
+            (range.from(), range.to())
         };
         if change_pos.contains(&open_pos) || change_pos.contains(&close_pos) {
             return Err(Error::CursorOverlap);

helix-core/src/textobject.rs

@@ -7,9 +7,9 @@ use crate::chars::{categorize_char, char_is_whitespace, CharCategory};
 use crate::graphemes::{next_grapheme_boundary, prev_grapheme_boundary};
 use crate::line_ending::rope_is_line_ending;
 use crate::movement::Direction;
-use crate::surround;
 use crate::syntax::LanguageConfiguration;
 use crate::Range;
+use crate::{surround, Syntax};
 
 fn find_word_boundary(slice: RopeSlice, mut pos: usize, direction: Direction, long: bool) -> usize {
     use CharCategory::{Eol, Whitespace};
@@ -199,25 +199,28 @@ pub fn textobject_paragraph(
 }
 
 pub fn textobject_pair_surround(
+    syntax: Option<&Syntax>,
     slice: RopeSlice,
     range: Range,
     textobject: TextObject,
     ch: char,
     count: usize,
 ) -> Range {
-    textobject_pair_surround_impl(slice, range, textobject, Some(ch), count)
+    textobject_pair_surround_impl(syntax, slice, range, textobject, Some(ch), count)
 }
 
 pub fn textobject_pair_surround_closest(
+    syntax: Option<&Syntax>,
     slice: RopeSlice,
     range: Range,
     textobject: TextObject,
     count: usize,
 ) -> Range {
-    textobject_pair_surround_impl(slice, range, textobject, None, count)
+    textobject_pair_surround_impl(syntax, slice, range, textobject, None, count)
 }
 
 fn textobject_pair_surround_impl(
+    syntax: Option<&Syntax>,
     slice: RopeSlice,
     range: Range,
     textobject: TextObject,
@@ -226,8 +229,7 @@ fn textobject_pair_surround_impl(
 ) -> Range {
     let pair_pos = match ch {
         Some(ch) => surround::find_nth_pairs_pos(slice, ch, range, count),
-        // Automatically find the closest surround pairs
-        None => surround::find_nth_closest_pairs_pos(slice, range, count),
+        None => surround::find_nth_closest_pairs_pos(syntax, slice, range, count),
     };
     pair_pos
         .map(|(anchor, head)| match textobject {

helix-term/src/commands.rs

@@ -5409,13 +5409,22 @@ fn select_textobject(cx: &mut Context, objtype: textobject::TextObject) {
                         'e' => textobject_treesitter("entry", range),
                         'p' => textobject::textobject_paragraph(text, range, objtype, count),
                         'm' => textobject::textobject_pair_surround_closest(
-                            text, range, objtype, count,
+                            doc.syntax(),
+                            text,
+                            range,
+                            objtype,
+                            count,
                         ),
                         'g' => textobject_change(range),
                         // TODO: cancel new ranges if inconsistent surround matches across lines
-                        ch if !ch.is_ascii_alphanumeric() => {
-                            textobject::textobject_pair_surround(text, range, objtype, ch, count)
-                        }
+                        ch if !ch.is_ascii_alphanumeric() => textobject::textobject_pair_surround(
+                            doc.syntax(),
+                            text,
+                            range,
+                            objtype,
+                            ch,
+                            count,
+                        ),
                         _ => range,
                     }
                 });
@@ -5440,7 +5449,7 @@ fn select_textobject(cx: &mut Context, objtype: textobject::TextObject) {
         ("c", "Comment (tree-sitter)"),
         ("T", "Test (tree-sitter)"),
         ("e", "Data structure entry (tree-sitter)"),
-        ("m", "Closest surrounding pair"),
+        ("m", "Closest surrounding pair (tree-sitter)"),
         ("g", "Change"),
         (" ", "... or any character acting as a pair"),
     ];
@@ -5454,7 +5463,7 @@ fn surround_add(cx: &mut Context) {
         // surround_len is the number of new characters being added.
         let (open, close, surround_len) = match event.char() {
             Some(ch) => {
-                let (o, c) = surround::get_pair(ch);
+                let (o, c) = match_brackets::get_pair(ch);
                 let mut open = Tendril::new();
                 open.push(o);
                 let mut close = Tendril::new();
@@ -5505,13 +5514,14 @@ fn surround_replace(cx: &mut Context) {
         let text = doc.text().slice(..);
         let selection = doc.selection(view.id);
 
-        let change_pos = match surround::get_surround_pos(text, selection, surround_ch, count) {
-            Ok(c) => c,
-            Err(err) => {
-                cx.editor.set_error(err.to_string());
-                return;
-            }
-        };
+        let change_pos =
+            match surround::get_surround_pos(doc.syntax(), text, selection, surround_ch, count) {
+                Ok(c) => c,
+                Err(err) => {
+                    cx.editor.set_error(err.to_string());
+                    return;
+                }
+            };
 
         let selection = selection.clone();
         let ranges: SmallVec<[Range; 1]> = change_pos.iter().map(|&p| Range::point(p)).collect();
@@ -5526,7 +5536,7 @@ fn surround_replace(cx: &mut Context) {
                 Some(to) => to,
                 None => return doc.set_selection(view.id, selection),
             };
-            let (open, close) = surround::get_pair(to);
+            let (open, close) = match_brackets::get_pair(to);
 
             // the changeset has to be sorted to allow nested surrounds
             let mut sorted_pos: Vec<(usize, char)> = Vec::new();
@@ -5563,13 +5573,14 @@ fn surround_delete(cx: &mut Context) {
         let text = doc.text().slice(..);
         let selection = doc.selection(view.id);
 
-        let mut change_pos = match surround::get_surround_pos(text, selection, surround_ch, count) {
-            Ok(c) => c,
-            Err(err) => {
-                cx.editor.set_error(err.to_string());
-                return;
-            }
-        };
+        let mut change_pos =
+            match surround::get_surround_pos(doc.syntax(), text, selection, surround_ch, count) {
+                Ok(c) => c,
+                Err(err) => {
+                    cx.editor.set_error(err.to_string());
+                    return;
+                }
+            };
         change_pos.sort_unstable(); // the changeset has to be sorted to allow nested surrounds
         let transaction =
             Transaction::change(doc.text(), change_pos.into_iter().map(|p| (p, p + 1, None)));