Yeah - I specifically use it all the time with ggplot2 because you often change one parameter to see if it did what you want. Inevitably it doesn't so you change it again and re-run that same bit of code.

Any suggestions on where to start on implementing something like this? I'd love to contribute but haven't ever even approached messing around with vscode in this way.

I experimented a little bit now in RStudio and here's my understanding of how Re-Run Previous works:

1. If no text was selected when previous command was run, Re-Run Previous effectively runs Ctrl+Enter as if the cursor was still at the location it was at when code was run previously. That is, if the text has changed since the code was run, it intelligently selects text as if Ctrl+Enter was used again.
2. If text was selected when previous command was run and it has not changed, Re-Run Previous runs that text again.
3. If text was selected when previous command was run and it HAS changed, Re-Run Previous does nothing.

Here's where the vscode-R run commands are set:

Most (all?) of these are implemented in rTerminal.ts. In general, they select text from the editor and then call runTextInTerm(text).

When these commands are run, we would need to save the cursor location (if no selection) or the selection range and text (if there was a selection). Then, a new command Re-Run Previous would need to be added that chooses text based on that saved cursor location and then calls runTextInTerm(text).

Instructions on how to get set up to make edits to the vscode-R extension are here: https://github.com/REditorSupport/vscode-R/wiki/Contributing Hopefully they are clear but if you get stuck let us know.

Ok this is a great start and perusing rTerminal.ts has be very useful to know what I've been missing. That feels like the keys to the kingdom.

One question:

we would need to save the cursor location

Could you elaborate on this, specifically how these are saved? My typescript is a bit lacking though I can make sense of the most of it (especially since I've got the dev environment setup). But the save step has me a little confused. How/where is that happening? Even just an example would be much appreciated.

Thanks for helping me out here.

Sure! At the moment these cursor locations aren't saved. We would need to create a variable to hold them, like this at around line 17:

let previousRunSelection: textEditor.selection | undefined = undefined

(Note that textEditor.selection is just my guess and might not be the right type here.)

Then for example in runSelection() at line 41 we would add something like

previousRunSelection = textEditor.selection

Then we'd add a new function like runPrevious() that would be something like

export async function runPrevious(): Promise<void> {
    if (previousRunSelection === undefined) {
        // no code has been run yet    
    }
    else if (previousRunSelection.start === previousRunSelection.end) {
        // previous run did not use a selection, so run the code as if cursor is still at previousRunSelection.start
    }
    // handle other cases
}

I definitely have quarto installed and use it all the time. It is just that re-run previous that I am really after.

Then either run cells above or run current cell would work. Unless you're running code from console/terminal?

Here's how I would tackle your situation:

library(ggplot)

data <- read_csv(...)

data %>%
   ggplot(aes(...) +
   geom_point()

Make your changes to code chunk 3 and use your run current cell keybind. Or run cells above if you made changes to chunks 1 or 2.