Xontrib: Allow using cocounut in rc files and @(...) syntax

[slacksystem]

I don't know if this would be possible but it would be really great if we could use coconut code in xonsh rc files, python-mode syntax within subprocess mode, and functions.

Example: rg -n "TODO" @( Path(".").rglob("*.py") |> filter$(p => not p.match("tests/**")) |> filter$(p => p.stat().st_mtime > time.time() - 86400) |> map$(.as_posix()) |> list

[evhub]

The reason that this isn't currently allowed is that it's really slow unless you can cache it to a file. It should be possible to cache it to a file, but that's the thing that would need to be implemented for this.

[slacksystem]

Do you mean that caching is something that would have to be implemented in coconut, or xonsh?

[evhub]

Coconut needs to implement it.

[slacksystem]

Is this something you'd consider implementing?