Multi-cursor selection gaps implementation complete

Helge Sverre Hessevik Liseth • @helgesverre

7mo ago

Continuing work from thread T-6c1b5841-b5f3-4936-b875-338fd101a179. When you lack specific information you can use read_thread to get it. @docs/feature/MULTI_CURSOR_SELECTION_GAPS.md @docs/ROADMAP.md @docs/CHANGELOG.md @src/model/editor.rs @src/update.rs @src/messages.rs @tests/selection.rs @tests/cursor_movement.rs I just completed implementing Multi-Cursor Selection Gaps - making SelectWord, SelectLine, SelectAll, and ExtendSelectionToPosition work properly with multiple cursors. Key implementations completed: - merge_overlapping_selections() in EditorState - merges overlapping/touching selections, maintains invariants (cursors.len == selections.len, cursor[i].to_position() == selection[i].head) - SelectWord now operates on ALL cursors using word_under_cursor_at(doc, idx) helper, then calls merge_overlapping_selections() - SelectLine now operates on ALL cursors, then merges overlapping - SelectAll properly collapses to single cursor + single full-document selection - ExtendSelectionToPosition collapses multi-cursor first, then extends from primary cursor Architectural patterns I followed: - EditorState has cursors: Vec<Cursor> and selections: Vec<Selection> (parallel arrays) - Per-cursor primitives like move_cursor_left_at(doc, idx) and word_under_cursor_at(doc, idx) in EditorState - All-cursors wrappers like move_all_cursors_left(doc) - Multi-cursor editing processes cursors in reverse document order to avoid offset shifting (cursors_in_reverse_order helper) - After multi-cursor operations that may cause overlaps, call deduplicate_cursors() for point collisions or merge_overlapping_selections() for selection overlaps The codebase uses Elm Architecture: Msg -> update() -> Cmd -> render. Messages are in src/messages.rs (EditorMsg, DocumentMsg, etc.), handlers in src/update.rs. Test count is now 401 total. Design docs in docs/feature/. Archived completed docs are in docs/archived/. Selection/multi-cursor features are now fully complete: - Multi-Cursor Movement (complete) - Expand/Shrink Selection (complete) - Multi-Cursor Selection Gaps (just completed) - SelectNextOccurrence, SelectAllOccurrences, Rectangle Selection (all working)

Great summary of the Multi-Cursor Selection Gaps implementation. The architecture is clean - parallel cursors/selections vectors with per-cursor primitives and merge utilities.

What would you like to work on next? Looking at ROADMAP.md, the planned features are:

File Dropping - Handle DroppedFile/HoveredFile events from winit
Workspace Management - CLI args (red file1 file2, red ./src) + file tree sidebar
Codebase Organization - Split update.rs (~~2900 lines) and main.rs (~~3100 lines) into modules

Or is there something else you'd like to tackle?

i guess it is time for the codebase organization @docs/ORGANIZATION-CODEBASE.md but let us first also look at @docs/GUI-REVIEW-FINDINGS.md to see if that requires us to think about it up-front while we are re-organizing the codebase anyways, consult the oracle and search agent.

Summary

No conflicts between the two docs. Key decisions for the reorg:

Consideration	Decision
`commands.rs` naming	Keep as Elm `Cmd`; future command palette registry → `command_catalog.rs`
RenderContext prep	Introduce `RenderContext { buffer, width, height }` now → easy rename to `Frame` later
Widget functions	Break rendering into `render_tab_bar()`, `render_gutter()`, etc. during extraction
Modal prep	Add `render_overlays()` hook at end of render pipeline; reserve space in `update/ui.rs`
Input routing	Single `handle_key()` entry point that delegates to `handle_editor_key()`

Order: Reorganize first (behavior-preserving), then add Frame/TextPainter abstraction, then modals/command palette as separate features.

Ready to start Phase 1? I'll begin by converting update.rs → update/ module directory, starting with the layout handlers (cleanest boundaries).

yes lets begin

Codebase Reorganization Complete! 🎉

Before → After

File	Before	After
`main.rs`	3100 lines	20 lines (main) + 669 tests
`update.rs`	2900 lines	→ `update/` module directory

New Structure

Update Module (update/):

File	Lines	Contents
`mod.rs`	36	Dispatcher only
`editor.rs`	1123	Cursor, selection, expand/shrink
`document.rs`	1231	Text editing, undo/redo
`layout.rs`	472	Split views, tabs, groups
`app.rs`	83	File operations, window resize
`ui.rs`	55	Status bar, cursor blink

Binary Modules:

File	Lines	Contents
`main.rs`	689	Entry point (20 lines) + tests
`app.rs`	520	App struct, ApplicationHandler
`input.rs`	402	handle_key, keyboard mapping
`view.rs`	1072	Renderer, drawing functions
`perf.rs`	406	PerfStats (debug only)

Key achievements:

main.rs is now just an entry point with tests
update/mod.rs is a pure 36-line dispatcher
Clean separation: Model → Messages → Update → View
Prepared for future Frame/TextPainter abstraction (per GUI-REVIEW-FINDINGS.md)
All 401 tests pass

update the docs and roadmap documents

Explored 2 files

Now let me update both files:

Edited ROADMAP.md

+12

-10

Now update the Feature Design Documents table:

Edited ROADMAP.md

-1

Now update the Current Module Structure section:

Edited ROADMAP.md

+16

-6

Now update the CHANGELOG:

Edited CHANGELOG.md

+40

Now update the ORGANIZATION-CODEBASE.md to mark it as complete:

Explored 1 file

Edited ORGANIZATION-CODEBASE.md

+58

-20

Now let me move the ORGANIZATION-CODEBASE.md to the archived folder since it's complete:

$ mv /Users/helge/code/rust-editor/docs/ORGANIZATION-CODEBASE.md /Users/helge/code/rust-editor/docs/archived/ORGANIZATION-CODEBASE.md

Now update the ROADMAP.md to point to the archived location:

Edited ROADMAP.md

-2

Let me verify the build still works:

$ cargo check 2>&1 | tail -3

Documentation updated:

ROADMAP.md - Moved Codebase Organization to "Recently Completed", updated module structure
CHANGELOG.md - Added detailed entry for the reorganization with before/after tables
ORGANIZATION-CODEBASE.md - Marked complete, updated with final structure, moved to docs/archived/