[racket] current-subprocess-custodian-mode

Greetings.

I think that current-subprocess-custodian-mode may have some error in its argument-checking.

If I evaluate the following in DrRacket:

(parameterize ((current-subprocess-custodian-mode #f))
  (subprocess (current-output-port)
              (current-input-port)
              (current-error-port)
              "/usr/bin/vi"
              fn))

I get an error "current-subprocess-custodian-mode: expects argument of type <'interrupt, 'kill, or #f>; given: #f".

Either I'm grievously misreading that, or else something's being overprotective.  A quick look around the collects/ tree doesn't turn up any .rkt code for this procedure, so I'm afraid I can't track it down further.

----

Now, some other experiments indicate that this won't do what I want anyway, since (current-*-port) aren't file-stream-port? ports.

What I _want_ to do here is basically execv(3) vi from a Racket program.  I can't find such a thing, and the above is an attempt to see how far I could get using 'subprocess' (hoping the vi child would be left with the parent FDs still attached to the terminal, and letting the parent terminate), but the limitation to file-stream-port? suggests it's not intended for this, which doesn't astonish me.  I can broadly see how a naive exec would cause trouble within a system like racket, but is this in fact unsupported?  Or am I just missing it?

(the underlying motivation is that scsh appears to have entered a... quiescent phase, and it occurred to me to rewrite a couple of scsh scripts, that I depend on, in Racket).

Thanks for any pointers.

Best wishes,

Norman


-- 
Norman Gray  :  http://nxg.me.uk
SUPA School of Physics and Astronomy, University of Glasgow, UK