Milestone 14 — Implementation Log

Plan: Milestone 14 - Rust Code Editor. Design: Code Editor Implementations.

Steps 1–5 done (2026-09-21) — the Rust editor opens, highlights, saves and switches; 107 native tests, 37 browser suites

Code Editor (Rust) (dev.moonkale.editor-code-native, opt-in) shows a text document in dioxus-code-editor: tree-sitter highlighting in Rust/wasm for every core language — Lean, Nix and Typst included, which CodeMirror’s bundle never had — with the CodeMirror panel’s toolbar (Save, Reload, Ctrl+S, dirty dot) and a CodeMirror switch; the CodeMirror panel gets a Rust switch; editor.implementation picks the default. The word under the caret is a Workspace signal now (cursor, cursor_word()), fed by both editors — CodeMirror already reported line and column, the Rust editor reads the textarea’s caret with one property read. Two dependency knots on the way: one tree-sitter runtime per binary (the index moved to arborium’s, P-113) and wasm’s missing stderr (P-114). The Rust terminal’s cut rows (P-112) re-measure on a timer and anchor to the bottom.

Steps as executed

#	step	outcome	notes
1	packages/editors/code-native: NativeCodeExtension (panels for editor_for(node) == "native", skipping markdown/flow like CodeMirror’s), NativeCodePanel (toolbar, CodeEditor, language_of, theme by app theme, Document.text from oninput), csrc/wasm_stubs.c + build.rs	✅ 2 unit tests; wasm client links; code-native.mjs: main.rs opens with 36 tree-sitter tokens, no CodeMirror mounted	editor-code-native.md
2	Workspace::{editor_choice, editor_for, choose_editor}, editor.implementation (settings + both extensions’ settings sections), CodeMirror’s panels() filter and Rust switch, on_panel_closed that respects a move	✅ code-native.mjs: CodeMirror → .cm-content with the edited text, Rust → back; lsp, highlight suites unchanged
3	Workspace::{cursor, set_cursor, cursor_word} + word_at (unit test); CodeMirror passes the column it already had; the Rust panel reads selectionStart on onkeyup/onclick/onselect (line_col from UTF-16 offsets, unit test) and shows ‹word› in its toolbar	✅ code-native.mjs: ‹u32› after moving the caret into u32
4	Rust terminal: 600 ms re-measure timer from onmounted, bottom-anchored screen	✅ terminal-native.mjs still passes; the desktop case (P-112) needs Daniel’s look — the E2E viewport never showed it
5	moonkale-index on arborium-tree-sitter + arborium-{rust,julia,python}	✅ the three extractor tests and index_source pass unchanged	index.md
6	verify, log, vault, catalogue	✅ full batch 37/37; this note; Extension Catalogue, JavaScript Inventory, Core Languages, Problem Log P-112–P-114

Answer to the question

Is the code editor aware of the word under the cursor? CodeMirror: yes, and since this milestone Rust is too — Workspace::cursor_word() gives the identifier under the caret of the active document, from the (line, column) the bundle reports on every selection change (throttled 250 ms); the mouse position stays on demand through the LSP hover path. Rust editor: the crate exposes nothing, so the panel reads the textarea’s selectionStart on caret-moving events (one document::eval, no bundle) and feeds the same signal; the pointer is not tracked. Detail in Code Editor Implementations.

What the user sees

• Extensions → Code Editor (Rust) on; its settings row (and the CodeMirror one) has Which editor opens a text file. Open .rs, .jl, .lean, .nix, .typ… — highlighted in the Rust editor; ‹word› in the toolbar follows the caret; Save/Reload/Ctrl+S as always.
• CodeMirror / Rust buttons in the toolbars move the open file between the editors (the text and the dirty state carry over; the browser’s undo history does not).
• The Rust terminal keeps its prompt in view when the panel changes size.

Deviations from the plan

1. The index changed tree-sitter runtimes — not planned; forced by Cargo’s links rule. The upside is real (the index parsers compile to wasm), the risk (arborium’s forks of the grammars drifting from upstream) is covered by the extractor tests.
2. wasm needed two C stubs of our own (stderr, fprintf) — arborium’s sysroot crate is never linked because nothing references it; reported upstream-worthy.
3. The Rust terminal fix is verified on the web only; the desktop symptom came from Daniel and is expected to be gone with the timer (the measured height now follows the tile within 0.6 s).
4. No modal chooser for editors (the plan’s decision): the setting is the default and the toolbar switches per document.

Numbers

• editors/code-native: 330 lines + 15 lines of C; arborium grammars for 20 languages add ~2 minutes to a clean build and ~1.8 MB to the wasm client.
• Tokens on main.rs (the fixture, 9 lines): 36 highlight spans.
• Tests: 107 native (+3), 37 browser suites (+1).