Feature suggestion: switch between console and shell (like radian/Julia/arf)

Request to make it possible for the Console to have a modal switch that puts it in shell mode. This is inspired by Julia's interactive shell, where typing ; puts you in "shell mode", wherein commands are interpreted as shell commands instead of Julia commands. This makes it possible to interleave interpreter commands and shell commands in the same history and reduces pane switching.

This feature has been imitated in Radian and in arf, where :shell puts you in shell mode.

Also requested on Bluesky: https://bsky.app/profile/geoeconomica.bsky.social/post/3mixxh7xsnk2m

Discussed in https://github.com/posit-dev/positron/discussions/12911

^{Originally posted by francisbarton April 9, 2026}
Prompted to post this by learning that radian is no longer under development.

Ever since starting to use Positron I have been very happy with the integrated R console. I used to use radian in VSCode, and I am also a Julia user. One neat Julia console feature, which radian adopted, was the ability to switch from console/REPL mode to shell mode with ; (and backspace to return to the console).

The "option to use radian" issue is understandably closed as won't but there is an invitation there to post feature "gaps" as requests on here. So here I am 😃.

A "switch to shell" mode feature would be a wonderful asset to Positron as it develops further.

No implementation files, tests, or entry points are identified. Start by reviewing the linked Positron discussion and the existing Console behavior, then compare the requested interaction with Julia, Radian, and arf. Done means the Console can switch between interpreter and shell modes while preserving the requested shared-history workflow.