Visual editor selection support (getSelectedText + selection-change e…

[stevehaigh]

Motivation

VS Code extensions can read the active editor's selection via window.activeTextEditor.selection, but Quarto's visual editor is a webview-based custom editor — its selection lives inside the webview and isn't visible to VS Code's text-editor API. As a result, extensions that act on the current selection (e.g. word-count tools, or sending a snippet to another command) work in source mode but go blind in visual mode. This PR exposes the visual editor's selection through Quarto's public extension API so those integrations work in both modes.

Summary

Adds read access to the Quarto visual editor's text selection, in two layers:

1. getSelectedText() — pull the current selection on demand

Plumbs a new getSelectedText() method through every layer of the editor RPC stack:

• EditorOperations.getSelectedText() and the Editor implementation (packages/editor)
• The EditorOperations object built in Editor.tsx (packages/editor-ui)
• The VSCodeVisualEditor interface and the VSC_VE_GetSelectedText RPC constant (packages/editor-types)
• The webview host server and client transport (apps/vscode-editor/sync.ts, apps/vscode/.../connection.ts)
• A quarto.editor.getSelectedText command returning the selection, or '' when no visual editor is active (apps/vscode/.../editor.ts)

Editor.getSelectedText() joins blocks with \n\n, preserves hard_break as a newline, and returns '' for an empty selection.

2. onDidChangeVisualEditorSelection — push selection changes to API consumers

Exposes a new event on the already-public QuartoExtensionApi:

onDidChangeVisualEditorSelection: vscode.Event<{ uri: vscode.Uri; selectedText: string }>

It rides the existing StateChangeEvent -> onEditorStateChanged plumbing:

• The selected text is carried in the onEditorStateChanged RPC payload (sync/cheap), forwarded through the webview transport.
• It is re-emitted on a vscode.EventEmitter exposed by createQuartoExtensionApi.

Design decisions:

• Push the text, not just a signal — the webview already has it, avoiding a round-trip.
• De-duplicate in Quarto (per-document, against the previous selection), but leave time-debouncing to consumers — StateChangeEvent fires on every cursor move.
• Empty selection ('') is a real event so consumers can reset UI on clear/blur.
• The getSelectedText command remains as a backward-compatible pull-based fallback.

Test plan

• Build the VS Code extension (yarn build-vscode) — green across all packages
• API tests pass (yarn test-vscode --label main --grep "Quarto Extension API"), including a new assertion that onDidChangeVisualEditorSelection is exposed
• Command test asserts quarto.editor.getSelectedText returns '' when no visual editor is active
• Manually: select text in the visual editor and confirm the command returns it and the event fires; confirm an empty selection emits ''

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[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR exposes the visual editor’s current text selection to VS Code extension consumers by adding a quarto.editor.getSelectedText command and a new public API event (onDidChangeVisualEditorSelection).

Changes:

• Added getSelectedText() plumbing from the ProseMirror editor through the webview RPC layer to the VS Code extension host.
• Introduced a public API event emitting { uri, selectedText } on visual editor state changes (with per-document de-duplication).
• Added VS Code extension tests covering the new command and updated the changelog.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
packages/editor/src/editor/editor.ts	Implements selection-to-text extraction with custom separators/leaf handling.
packages/editor-ui/src/editor/Editor.tsx	Exposes getSelectedText() via the UI editor ref facade.
packages/editor-types/src/vscode.ts	Adds RPC constant + API surface for getSelectedText and extends host callback signature.
apps/vscode/src/providers/editor/connection.ts	Wires new RPC method and updated host callback argument mapping.
apps/vscode-editor/src/sync.ts	Sends selected text on state change and exposes RPC endpoint to query it.
apps/vscode/src/providers/editor/editor.ts	Adds command quarto.editor.getSelectedText and emits selection-change events.
apps/vscode/src/main.ts	Creates and wires a shared EventEmitter into the public extension API.
apps/vscode/src/api.ts	Defines VisualEditorSelection and adds onDidChangeVisualEditorSelection to the public API.
apps/vscode/src/test/editor-commands.test.ts	Adds integration test for the new command when no visual editor is active.
apps/vscode/src/test/api.test.ts	Asserts the new API event exists.
apps/vscode/CHANGELOG.md	Documents the new command and API event.

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[stevehaigh]

Note that this PR will help with future work to address issue #717