[ESS] launch help.start() in EWW browser

[Tyler Smith]

On Wed, Sep 10, 2025, at 6:42 AM, Naresh Gurbuxani wrote:
>  It does not work in Linux terminal emacs run inside AWS SageMaker.  
> Here it needs to open 
> /home/ec2-user/anaconda3/envs/R/lib/R/doc/html/index.html

This is interesting. If it needs to open a local file, that suggests the http server is not started. Can you tell me what the output of `print(tools::startDynamicHelp(NA))` (run from within R) is in that situation? The new version of my function (below) may fix this.

> On Mac emacs GUI, this function does not work with default settings.  
> This is the message displayed in in *eww* buffer:
> Loading http://127.0.0.1:ting httpd help server ... done
> [1] 23824/doc/html/index.html…

This is helpful! My original code didn't account for the extra text emitted when the http server is started the first time. The following should fix that:

```
(defun ess-eww ()
  (interactive)
  (let ((BUF (generate-new-buffer "URL"))
        (PORT)) 
    (ess-command "print(tools::startDynamicHelp(NA))" BUF)
    (with-current-buffer BUF
      (setq PORT (buffer-substring (search-forward-regexp "\\[1\\] ") (point-max)))
      (message (buffer-substring (point-min) (point-max))))
    (kill-buffer BUF)
    (eww (concat "http://127.0.0.1:" PORT "/doc/html/index.html"))))
```

This may also fix the problem in the Linux terminal. It works here using terminal Emacs (on Debian).

Question for the ESS devs - is there a simpler way to get text from the R process into Elisp? I've used `ess-command`, and then collected the relevant info out of the buffer the result is printed to. This requires a bit of fussing to get to the value I want (via `search-forward-regexp`). That might be brittle. If I could directly transfer the first value of an R vector into an Elisp variable that would be better.

- tyler