selections_collection.rs

  1use std::{
  2    cell::Ref,
  3    cmp, iter, mem,
  4    ops::{Deref, Range, Sub},
  5    sync::Arc,
  6};
  7
  8use collections::HashMap;
  9use gpui::{AppContext, ModelHandle, MutableAppContext};
 10use itertools::Itertools;
 11use language::{rope::TextDimension, Bias, Point, Selection, SelectionGoal, ToPoint};
 12use util::post_inc;
 13
 14use crate::{
 15    display_map::{DisplayMap, DisplaySnapshot, ToDisplayPoint},
 16    Anchor, DisplayPoint, ExcerptId, MultiBuffer, MultiBufferSnapshot, SelectMode, ToOffset,
 17};
 18
 19#[derive(Clone)]
 20pub struct PendingSelection {
 21    pub selection: Selection<Anchor>,
 22    pub mode: SelectMode,
 23}
 24
 25#[derive(Clone)]
 26pub struct SelectionsCollection {
 27    display_map: ModelHandle<DisplayMap>,
 28    buffer: ModelHandle<MultiBuffer>,
 29    pub next_selection_id: usize,
 30    pub line_mode: bool,
 31    disjoint: Arc<[Selection<Anchor>]>,
 32    pending: Option<PendingSelection>,
 33}
 34
 35impl SelectionsCollection {
 36    pub fn new(display_map: ModelHandle<DisplayMap>, buffer: ModelHandle<MultiBuffer>) -> Self {
 37        Self {
 38            display_map,
 39            buffer,
 40            next_selection_id: 1,
 41            line_mode: false,
 42            disjoint: Arc::from([]),
 43            pending: Some(PendingSelection {
 44                selection: Selection {
 45                    id: 0,
 46                    start: Anchor::min(),
 47                    end: Anchor::min(),
 48                    reversed: false,
 49                    goal: SelectionGoal::None,
 50                },
 51                mode: SelectMode::Character,
 52            }),
 53        }
 54    }
 55
 56    fn display_map(&self, cx: &mut MutableAppContext) -> DisplaySnapshot {
 57        self.display_map.update(cx, |map, cx| map.snapshot(cx))
 58    }
 59
 60    fn buffer<'a>(&self, cx: &'a AppContext) -> Ref<'a, MultiBufferSnapshot> {
 61        self.buffer.read(cx).read(cx)
 62    }
 63
 64    pub fn set_state(&mut self, other: &SelectionsCollection) {
 65        self.next_selection_id = other.next_selection_id;
 66        self.line_mode = other.line_mode;
 67        self.disjoint = other.disjoint.clone();
 68        self.pending = other.pending.clone();
 69    }
 70
 71    pub fn count<'a>(&self) -> usize {
 72        let mut count = self.disjoint.len();
 73        if self.pending.is_some() {
 74            count += 1;
 75        }
 76        count
 77    }
 78
 79    pub fn disjoint_anchors(&self) -> Arc<[Selection<Anchor>]> {
 80        self.disjoint.clone()
 81    }
 82
 83    pub fn pending_anchor(&self) -> Option<Selection<Anchor>> {
 84        self.pending
 85            .as_ref()
 86            .map(|pending| pending.selection.clone())
 87    }
 88
 89    pub fn pending<D: TextDimension + Ord + Sub<D, Output = D>>(
 90        &self,
 91        cx: &AppContext,
 92    ) -> Option<Selection<D>> {
 93        self.pending_anchor()
 94            .as_ref()
 95            .map(|pending| pending.map(|p| p.summary::<D>(&self.buffer(cx))))
 96    }
 97
 98    pub fn pending_mode(&self) -> Option<SelectMode> {
 99        self.pending.as_ref().map(|pending| pending.mode.clone())
100    }
101
102    pub fn all<'a, D>(&self, cx: &AppContext) -> Vec<Selection<D>>
103    where
104        D: 'a + TextDimension + Ord + Sub<D, Output = D> + std::fmt::Debug,
105    {
106        let disjoint_anchors = &self.disjoint;
107        let mut disjoint =
108            resolve_multiple::<D, _>(disjoint_anchors.iter(), &self.buffer(cx)).peekable();
109
110        let mut pending_opt = self.pending::<D>(cx);
111
112        iter::from_fn(move || {
113            if let Some(pending) = pending_opt.as_mut() {
114                while let Some(next_selection) = disjoint.peek() {
115                    if pending.start <= next_selection.end && pending.end >= next_selection.start {
116                        let next_selection = disjoint.next().unwrap();
117                        if next_selection.start < pending.start {
118                            pending.start = next_selection.start;
119                        }
120                        if next_selection.end > pending.end {
121                            pending.end = next_selection.end;
122                        }
123                    } else if next_selection.end < pending.start {
124                        return disjoint.next();
125                    } else {
126                        break;
127                    }
128                }
129
130                pending_opt.take()
131            } else {
132                disjoint.next()
133            }
134        })
135        .collect()
136    }
137
138    // Returns all of the selections, adjusted to take into account the selection line_mode
139    pub fn all_adjusted(&self, cx: &mut MutableAppContext) -> Vec<Selection<Point>> {
140        let mut selections = self.all::<Point>(cx);
141        if self.line_mode {
142            let map = self.display_map(cx);
143            for selection in &mut selections {
144                let new_range = map.expand_to_line(selection.range());
145                selection.start = new_range.start;
146                selection.end = new_range.end;
147            }
148        }
149        selections
150    }
151
152    pub fn all_adjusted_display(
153        &self,
154        cx: &mut MutableAppContext,
155    ) -> (DisplaySnapshot, Vec<Selection<DisplayPoint>>) {
156        if self.line_mode {
157            let selections = self.all::<Point>(cx);
158            let map = self.display_map(cx);
159            let result = selections
160                .into_iter()
161                .map(|mut selection| {
162                    let new_range = map.expand_to_line(selection.range());
163                    selection.start = new_range.start;
164                    selection.end = new_range.end;
165                    selection.map(|point| point.to_display_point(&map))
166                })
167                .collect();
168            (map, result)
169        } else {
170            self.all_display(cx)
171        }
172    }
173
174    pub fn disjoint_in_range<'a, D>(
175        &self,
176        range: Range<Anchor>,
177        cx: &AppContext,
178    ) -> Vec<Selection<D>>
179    where
180        D: 'a + TextDimension + Ord + Sub<D, Output = D> + std::fmt::Debug,
181    {
182        let buffer = self.buffer(cx);
183        let start_ix = match self
184            .disjoint
185            .binary_search_by(|probe| probe.end.cmp(&range.start, &buffer))
186        {
187            Ok(ix) | Err(ix) => ix,
188        };
189        let end_ix = match self
190            .disjoint
191            .binary_search_by(|probe| probe.start.cmp(&range.end, &buffer))
192        {
193            Ok(ix) => ix + 1,
194            Err(ix) => ix,
195        };
196        resolve_multiple(&self.disjoint[start_ix..end_ix], &buffer).collect()
197    }
198
199    pub fn all_display(
200        &self,
201        cx: &mut MutableAppContext,
202    ) -> (DisplaySnapshot, Vec<Selection<DisplayPoint>>) {
203        let display_map = self.display_map(cx);
204        let selections = self
205            .all::<Point>(cx)
206            .into_iter()
207            .map(|selection| selection.map(|point| point.to_display_point(&display_map)))
208            .collect();
209        (display_map, selections)
210    }
211
212    pub fn newest_anchor(&self) -> &Selection<Anchor> {
213        self.pending
214            .as_ref()
215            .map(|s| &s.selection)
216            .or_else(|| self.disjoint.iter().max_by_key(|s| s.id))
217            .unwrap()
218    }
219
220    pub fn newest<D: TextDimension + Ord + Sub<D, Output = D>>(
221        &self,
222        cx: &AppContext,
223    ) -> Selection<D> {
224        resolve(self.newest_anchor(), &self.buffer(cx))
225    }
226
227    pub fn newest_display(&self, cx: &mut MutableAppContext) -> Selection<DisplayPoint> {
228        let display_map = self.display_map(cx);
229        let selection = self
230            .newest_anchor()
231            .map(|point| point.to_display_point(&display_map));
232        selection
233    }
234
235    pub fn oldest_anchor(&self) -> &Selection<Anchor> {
236        self.disjoint
237            .iter()
238            .min_by_key(|s| s.id)
239            .or_else(|| self.pending.as_ref().map(|p| &p.selection))
240            .unwrap()
241    }
242
243    pub fn oldest<D: TextDimension + Ord + Sub<D, Output = D>>(
244        &self,
245        cx: &AppContext,
246    ) -> Selection<D> {
247        resolve(self.oldest_anchor(), &self.buffer(cx))
248    }
249
250    pub fn first<D: TextDimension + Ord + Sub<D, Output = D>>(
251        &self,
252        cx: &AppContext,
253    ) -> Selection<D> {
254        self.all(cx).first().unwrap().clone()
255    }
256
257    pub fn last<D: TextDimension + Ord + Sub<D, Output = D>>(
258        &self,
259        cx: &AppContext,
260    ) -> Selection<D> {
261        self.all(cx).last().unwrap().clone()
262    }
263
264    #[cfg(any(test, feature = "test-support"))]
265    pub fn ranges<D: TextDimension + Ord + Sub<D, Output = D> + std::fmt::Debug>(
266        &self,
267        cx: &AppContext,
268    ) -> Vec<Range<D>> {
269        self.all::<D>(cx)
270            .iter()
271            .map(|s| {
272                if s.reversed {
273                    s.end.clone()..s.start.clone()
274                } else {
275                    s.start.clone()..s.end.clone()
276                }
277            })
278            .collect()
279    }
280
281    #[cfg(any(test, feature = "test-support"))]
282    pub fn display_ranges(&self, cx: &mut MutableAppContext) -> Vec<Range<DisplayPoint>> {
283        let display_map = self.display_map(cx);
284        self.disjoint_anchors()
285            .iter()
286            .chain(self.pending_anchor().as_ref())
287            .map(|s| {
288                if s.reversed {
289                    s.end.to_display_point(&display_map)..s.start.to_display_point(&display_map)
290                } else {
291                    s.start.to_display_point(&display_map)..s.end.to_display_point(&display_map)
292                }
293            })
294            .collect()
295    }
296
297    pub fn build_columnar_selection(
298        &mut self,
299        display_map: &DisplaySnapshot,
300        row: u32,
301        columns: &Range<u32>,
302        reversed: bool,
303    ) -> Option<Selection<Point>> {
304        let is_empty = columns.start == columns.end;
305        let line_len = display_map.line_len(row);
306        if columns.start < line_len || (is_empty && columns.start == line_len) {
307            let start = DisplayPoint::new(row, columns.start);
308            let end = DisplayPoint::new(row, cmp::min(columns.end, line_len));
309
310            Some(Selection {
311                id: post_inc(&mut self.next_selection_id),
312                start: start.to_point(display_map),
313                end: end.to_point(display_map),
314                reversed,
315                goal: SelectionGoal::ColumnRange {
316                    start: columns.start,
317                    end: columns.end,
318                },
319            })
320        } else {
321            None
322        }
323    }
324
325    pub(crate) fn change_with<R>(
326        &mut self,
327        cx: &mut MutableAppContext,
328        change: impl FnOnce(&mut MutableSelectionsCollection) -> R,
329    ) -> (bool, R) {
330        let mut mutable_collection = MutableSelectionsCollection {
331            collection: self,
332            selections_changed: false,
333            cx,
334        };
335
336        let result = change(&mut mutable_collection);
337        assert!(
338            !mutable_collection.disjoint.is_empty() || mutable_collection.pending.is_some(),
339            "There must be at least one selection"
340        );
341        (mutable_collection.selections_changed, result)
342    }
343}
344
345pub struct MutableSelectionsCollection<'a> {
346    collection: &'a mut SelectionsCollection,
347    selections_changed: bool,
348    cx: &'a mut MutableAppContext,
349}
350
351impl<'a> MutableSelectionsCollection<'a> {
352    fn display_map(&mut self) -> DisplaySnapshot {
353        self.collection.display_map(self.cx)
354    }
355
356    fn buffer(&self) -> Ref<MultiBufferSnapshot> {
357        self.collection.buffer(self.cx)
358    }
359
360    pub fn clear_disjoint(&mut self) {
361        self.collection.disjoint = Arc::from([]);
362    }
363
364    pub fn delete(&mut self, selection_id: usize) {
365        let mut changed = false;
366        self.collection.disjoint = self
367            .disjoint
368            .into_iter()
369            .filter(|selection| {
370                let found = selection.id == selection_id;
371                changed |= found;
372                !found
373            })
374            .cloned()
375            .collect();
376
377        self.selections_changed |= changed;
378    }
379
380    pub fn clear_pending(&mut self) {
381        if self.collection.pending.is_some() {
382            self.collection.pending = None;
383            self.selections_changed = true;
384        }
385    }
386
387    pub fn set_pending_range(&mut self, range: Range<Anchor>, mode: SelectMode) {
388        self.collection.pending = Some(PendingSelection {
389            selection: Selection {
390                id: post_inc(&mut self.collection.next_selection_id),
391                start: range.start,
392                end: range.end,
393                reversed: false,
394                goal: SelectionGoal::None,
395            },
396            mode,
397        });
398        self.selections_changed = true;
399    }
400
401    pub fn set_pending(&mut self, selection: Selection<Anchor>, mode: SelectMode) {
402        self.collection.pending = Some(PendingSelection { selection, mode });
403        self.selections_changed = true;
404    }
405
406    pub fn try_cancel(&mut self) -> bool {
407        if let Some(pending) = self.collection.pending.take() {
408            if self.disjoint.is_empty() {
409                self.collection.disjoint = Arc::from([pending.selection]);
410            }
411            self.selections_changed = true;
412            return true;
413        }
414
415        let mut oldest = self.oldest_anchor().clone();
416        if self.count() > 1 {
417            self.collection.disjoint = Arc::from([oldest]);
418            self.selections_changed = true;
419            return true;
420        }
421
422        if !oldest.start.cmp(&oldest.end, &self.buffer()).is_eq() {
423            let head = oldest.head();
424            oldest.start = head.clone();
425            oldest.end = head;
426            self.collection.disjoint = Arc::from([oldest]);
427            self.selections_changed = true;
428            return true;
429        }
430
431        return false;
432    }
433
434    pub fn insert_range<T>(&mut self, range: Range<T>)
435    where
436        T: 'a + ToOffset + ToPoint + TextDimension + Ord + Sub<T, Output = T> + std::marker::Copy,
437    {
438        let mut selections = self.all(self.cx);
439        let mut start = range.start.to_offset(&self.buffer());
440        let mut end = range.end.to_offset(&self.buffer());
441        let reversed = if start > end {
442            mem::swap(&mut start, &mut end);
443            true
444        } else {
445            false
446        };
447        selections.push(Selection {
448            id: post_inc(&mut self.collection.next_selection_id),
449            start,
450            end,
451            reversed,
452            goal: SelectionGoal::None,
453        });
454        self.select(selections);
455    }
456
457    pub fn select<T>(&mut self, mut selections: Vec<Selection<T>>)
458    where
459        T: ToOffset + ToPoint + Ord + std::marker::Copy + std::fmt::Debug,
460    {
461        let buffer = self.buffer.read(self.cx).snapshot(self.cx);
462        selections.sort_unstable_by_key(|s| s.start);
463        // Merge overlapping selections.
464        let mut i = 1;
465        while i < selections.len() {
466            if selections[i - 1].end >= selections[i].start {
467                let removed = selections.remove(i);
468                if removed.start < selections[i - 1].start {
469                    selections[i - 1].start = removed.start;
470                }
471                if removed.end > selections[i - 1].end {
472                    selections[i - 1].end = removed.end;
473                }
474            } else {
475                i += 1;
476            }
477        }
478
479        self.collection.disjoint = Arc::from_iter(selections.into_iter().map(|selection| {
480            let end_bias = if selection.end > selection.start {
481                Bias::Left
482            } else {
483                Bias::Right
484            };
485            Selection {
486                id: selection.id,
487                start: buffer.anchor_after(selection.start),
488                end: buffer.anchor_at(selection.end, end_bias),
489                reversed: selection.reversed,
490                goal: selection.goal,
491            }
492        }));
493
494        self.collection.pending = None;
495        self.selections_changed = true;
496    }
497
498    pub fn select_anchors(&mut self, selections: Vec<Selection<Anchor>>) {
499        let buffer = self.buffer.read(self.cx).snapshot(self.cx);
500        let resolved_selections =
501            resolve_multiple::<usize, _>(&selections, &buffer).collect::<Vec<_>>();
502        self.select(resolved_selections);
503    }
504
505    pub fn select_ranges<I, T>(&mut self, ranges: I)
506    where
507        I: IntoIterator<Item = Range<T>>,
508        T: ToOffset,
509    {
510        let buffer = self.buffer.read(self.cx).snapshot(self.cx);
511        let selections = ranges
512            .into_iter()
513            .map(|range| {
514                let mut start = range.start.to_offset(&buffer);
515                let mut end = range.end.to_offset(&buffer);
516                let reversed = if start > end {
517                    mem::swap(&mut start, &mut end);
518                    true
519                } else {
520                    false
521                };
522                Selection {
523                    id: post_inc(&mut self.collection.next_selection_id),
524                    start,
525                    end,
526                    reversed,
527                    goal: SelectionGoal::None,
528                }
529            })
530            .collect::<Vec<_>>();
531
532        self.select(selections)
533    }
534
535    pub fn select_anchor_ranges<I: IntoIterator<Item = Range<Anchor>>>(&mut self, ranges: I) {
536        let buffer = self.buffer.read(self.cx).snapshot(self.cx);
537        let selections = ranges
538            .into_iter()
539            .map(|range| {
540                let mut start = range.start;
541                let mut end = range.end;
542                let reversed = if start.cmp(&end, &buffer).is_gt() {
543                    mem::swap(&mut start, &mut end);
544                    true
545                } else {
546                    false
547                };
548                Selection {
549                    id: post_inc(&mut self.collection.next_selection_id),
550                    start,
551                    end,
552                    reversed,
553                    goal: SelectionGoal::None,
554                }
555            })
556            .collect::<Vec<_>>();
557
558        self.select_anchors(selections)
559    }
560
561    #[cfg(any(test, feature = "test-support"))]
562    pub fn select_display_ranges<T>(&mut self, ranges: T)
563    where
564        T: IntoIterator<Item = Range<DisplayPoint>>,
565    {
566        let display_map = self.display_map();
567        let selections = ranges
568            .into_iter()
569            .map(|range| {
570                let mut start = range.start;
571                let mut end = range.end;
572                let reversed = if start > end {
573                    mem::swap(&mut start, &mut end);
574                    true
575                } else {
576                    false
577                };
578                Selection {
579                    id: post_inc(&mut self.collection.next_selection_id),
580                    start: start.to_point(&display_map),
581                    end: end.to_point(&display_map),
582                    reversed,
583                    goal: SelectionGoal::None,
584                }
585            })
586            .collect();
587        self.select(selections);
588    }
589
590    pub fn move_with(
591        &mut self,
592        mut move_selection: impl FnMut(&DisplaySnapshot, &mut Selection<DisplayPoint>),
593    ) {
594        let mut changed = false;
595        let display_map = self.display_map();
596        let selections = self
597            .all::<Point>(self.cx)
598            .into_iter()
599            .map(|selection| {
600                let mut moved_selection =
601                    selection.map(|point| point.to_display_point(&display_map));
602                move_selection(&display_map, &mut moved_selection);
603                let moved_selection =
604                    moved_selection.map(|display_point| display_point.to_point(&display_map));
605                if selection != moved_selection {
606                    changed = true;
607                }
608                moved_selection
609            })
610            .collect();
611
612        if changed {
613            self.select(selections)
614        }
615    }
616
617    pub fn move_heads_with(
618        &mut self,
619        mut update_head: impl FnMut(
620            &DisplaySnapshot,
621            DisplayPoint,
622            SelectionGoal,
623        ) -> (DisplayPoint, SelectionGoal),
624    ) {
625        self.move_with(|map, selection| {
626            let (new_head, new_goal) = update_head(map, selection.head(), selection.goal);
627            selection.set_head(new_head, new_goal);
628        });
629    }
630
631    pub fn move_cursors_with(
632        &mut self,
633        mut update_cursor_position: impl FnMut(
634            &DisplaySnapshot,
635            DisplayPoint,
636            SelectionGoal,
637        ) -> (DisplayPoint, SelectionGoal),
638    ) {
639        self.move_with(|map, selection| {
640            let (cursor, new_goal) = update_cursor_position(map, selection.head(), selection.goal);
641            selection.collapse_to(cursor, new_goal)
642        });
643    }
644
645    pub fn replace_cursors_with(
646        &mut self,
647        mut find_replacement_cursors: impl FnMut(&DisplaySnapshot) -> Vec<DisplayPoint>,
648    ) {
649        let display_map = self.display_map();
650        let new_selections = find_replacement_cursors(&display_map)
651            .into_iter()
652            .map(|cursor| {
653                let cursor_point = cursor.to_point(&display_map);
654                Selection {
655                    id: post_inc(&mut self.collection.next_selection_id),
656                    start: cursor_point,
657                    end: cursor_point,
658                    reversed: false,
659                    goal: SelectionGoal::None,
660                }
661            })
662            .collect();
663        self.select(new_selections);
664    }
665
666    /// Compute new ranges for any selections that were located in excerpts that have
667    /// since been removed.
668    ///
669    /// Returns a `HashMap` indicating which selections whose former head position
670    /// was no longer present. The keys of the map are selection ids. The values are
671    /// the id of the new excerpt where the head of the selection has been moved.
672    pub fn refresh(&mut self) -> HashMap<usize, ExcerptId> {
673        let mut pending = self.collection.pending.take();
674        let mut selections_with_lost_position = HashMap::default();
675
676        let anchors_with_status = {
677            let buffer = self.buffer();
678            let disjoint_anchors = self
679                .disjoint
680                .iter()
681                .flat_map(|selection| [&selection.start, &selection.end]);
682            buffer.refresh_anchors(disjoint_anchors)
683        };
684        let adjusted_disjoint: Vec<_> = anchors_with_status
685            .chunks(2)
686            .map(|selection_anchors| {
687                let (anchor_ix, start, kept_start) = selection_anchors[0].clone();
688                let (_, end, kept_end) = selection_anchors[1].clone();
689                let selection = &self.disjoint[anchor_ix / 2];
690                let kept_head = if selection.reversed {
691                    kept_start
692                } else {
693                    kept_end
694                };
695                if !kept_head {
696                    selections_with_lost_position
697                        .insert(selection.id, selection.head().excerpt_id.clone());
698                }
699
700                Selection {
701                    id: selection.id,
702                    start,
703                    end,
704                    reversed: selection.reversed,
705                    goal: selection.goal,
706                }
707            })
708            .collect();
709
710        if !adjusted_disjoint.is_empty() {
711            let resolved_selections =
712                resolve_multiple(adjusted_disjoint.iter(), &self.buffer()).collect();
713            self.select::<usize>(resolved_selections);
714        }
715
716        if let Some(pending) = pending.as_mut() {
717            let buffer = self.buffer();
718            let anchors =
719                buffer.refresh_anchors([&pending.selection.start, &pending.selection.end]);
720            let (_, start, kept_start) = anchors[0].clone();
721            let (_, end, kept_end) = anchors[1].clone();
722            let kept_head = if pending.selection.reversed {
723                kept_start
724            } else {
725                kept_end
726            };
727            if !kept_head {
728                selections_with_lost_position.insert(
729                    pending.selection.id,
730                    pending.selection.head().excerpt_id.clone(),
731                );
732            }
733
734            pending.selection.start = start;
735            pending.selection.end = end;
736        }
737        self.collection.pending = pending;
738        self.selections_changed = true;
739
740        selections_with_lost_position
741    }
742}
743
744impl<'a> Deref for MutableSelectionsCollection<'a> {
745    type Target = SelectionsCollection;
746    fn deref(&self) -> &Self::Target {
747        self.collection
748    }
749}
750
751// Panics if passed selections are not in order
752pub fn resolve_multiple<'a, D, I>(
753    selections: I,
754    snapshot: &MultiBufferSnapshot,
755) -> impl 'a + Iterator<Item = Selection<D>>
756where
757    D: TextDimension + Ord + Sub<D, Output = D> + std::fmt::Debug,
758    I: 'a + IntoIterator<Item = &'a Selection<Anchor>>,
759{
760    let (to_summarize, selections) = selections.into_iter().tee();
761    let mut summaries = snapshot
762        .summaries_for_anchors::<D, _>(
763            to_summarize
764                .flat_map(|s| [&s.start, &s.end])
765                .collect::<Vec<_>>(),
766        )
767        .into_iter();
768    selections.map(move |s| Selection {
769        id: s.id,
770        start: summaries.next().unwrap(),
771        end: summaries.next().unwrap(),
772        reversed: s.reversed,
773        goal: s.goal,
774    })
775}
776
777fn resolve<D: TextDimension + Ord + Sub<D, Output = D>>(
778    selection: &Selection<Anchor>,
779    buffer: &MultiBufferSnapshot,
780) -> Selection<D> {
781    selection.map(|p| p.summary::<D>(&buffer))
782}