Left assignment operator shortcut overrides macOS keyboard shortcut outside of R contexts in Quarto files

[andrewheiss]

System details:

Positron and OS details:

Positron Version: 2025.03.0 (Universal) build 116
Code - OSS Version: 1.96.0
Commit: 7f0f938
Date: 2025-03-01T18:51:44.014Z
Electron: 32.2.6
Chromium: 128.0.6613.186
Node.js: 20.18.1
V8: 12.8.374.38-electron.0
OS: Darwin arm64 24.3.0

Interpreter details:

R 4.4.2 + Quarto 1.7.13

Describe the issue:

(I'm not sure if this is a Quarto extension issue or a Positron issue—it's weird behavior nonetheless.)

On macOS, the keystroke ⌥- (alt/option + -) inserts an en-dash (–). In Positron (inheriting from RStudio settings), ⌥- inserts the left assignment operator <-. That's all great and fine—there's rarely any reason to use proper en-dashes in R code (beyond things like typographically correct plot titles).

Positron includes a keybinding setting in the R language pack called 'R: Insert the "<-" assignment operator', which contains this:

{
  "key": "alt+-",
  "command": "r.insertLeftAssignment",
  "when": "editorTextFocus && editorLangId == 'r' || editorTextFocus && quarto.document.languageId == 'r'"
}

It makes Positron insert a <- in R scripts and Quarto documents that use R.

However, it seems to be a little too aggressive in when it is enabled. Here are some little videos to illustrate what's happening…

Steps to reproduce the issue:

On macOS, in a new Quarto document with no code chunks, alt+- inserts an en-dash as expected:

part-1.mov

If a Python chunk is added, alt+- continues to insert an en-dash, both in the code chunk and in the Markdown area. This is good and expected—<- isn't a thing in Python:

part-2.mov

If an R chunk is added, alt+- inserts a <- in the R chunk, which is good and expected, BUT it also inserts a <- outside of the chunk in the Markdown. This is unexpected.

part-3.mov

If the R chunk is removed, alt+- returns to working with en-dashes:

part-4.mov

Essentially, if there's an R chunk anywhere in a Quarto document, alt+- inserts <- in all contexts (YAML, Markdown, R). If the document contains chunks with multiple languages (e.g., R and Python), alt+- will insert <- in the other language chunks too. The existence of an R chunk enables the left assignment shortcut for the whole document.

Expected or desired behavior

It would be nice if the alt+- shortcut could be limited to only R code chunks. My current workaround is to use a systemwide keyboard shortcut (;enn) that expands to an en-dash—I just have to remember to use it when working in Markdown in Positron 🤷‍♂️

[juliasilge]

To get this working better, we need to implement a context key that is like quarto.cell.languageId, similar to how we implemented quarto.document.languageId in quarto-dev/quarto#608. That was my original goal in that PR, but everything I tried there for a per-cell context key did NOT work well; we'd need to revisit and see if we can find a better approach.