[Rd] Is an R sub-session somehow possible?

[Philippe Grosjean]

Hello,

Di you already look at svSocket (try the version on R-forge that 
corrects a couple of bugs recently -will be soon on CRAN, but only after 
further testing-)? It uses Tcl that already benefits from the modified 
even loop you mention, and it is well-tested since a long time since the 
tcltk package is a recommended R package and is widely used.

With svSocket, you can easily do something like calltip, or completion 
list calculation while R is processing other commands, say at the 
command line, or through other calls to svSocket: it manages multiple 
clients simultaneously (or multiple connections from the same client, 
say, one for evaluation of R code, and another one to get calltip or 
completion list calculation, no matter if R is doing other calculations 
or not). If you want to get inspiration, you can inspect how SciViews-K 
is implemented (http://www.sciviews.org/SciViews-K).
Best,

Philippe

..............................................<°}))><........
  ) ) ) ) )
( ( ( ( (    Prof. Philippe Grosjean
  ) ) ) ) )
( ( ( ( (    Numerical Ecology of Aquatic Systems
  ) ) ) ) )   Mons University, Belgium
( ( ( ( (
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On 08/09/10 00:27, ghostwheel wrote:
>
>
> Simon Urbanek wrote:
>>
>>
>>
>> It doesn't really matter where the R is as long as you have some way of
>> getting at the results. You are still leaving us in the dark as of what
>> exactly you do (technically) so there is not much detail we can provide...
>>
>>
>
> Sorry, I'll try to provide more detail:
>
> I am trying to provide a good connection between the TeXmacs editor and R.
> (A really nice overview of such connections can be found in
> http://www.r-project.org/conferences/useR-2004/abstracts/supplements/Urbanek.pdf
> ;)
> What I do is fake a terminal, and interact with the command line interface
> to R (something like what the program 'expect' does). To detect that R is
> waiting for input I have to check various properties of the terminal. Not
> really pretty.
> What happens is that:
> 1. TeXmacs sends me a string to execute.
> 2. I pass it to R, and wait for a prompt.
> 3. I pass all of R's return, somewhat processed back to TeXmacs. Thus, when
> I want to put a graphics inside TeXmacs' buffer, I have to print something
> like 'start postscipt graphics', then the postscript file, then 'end
> postscript'.
>
> When the user asks for tab completion, TeXmacs sends me a special message
> saying that this string needs to be completed. I call a function in R, and
> return the result.
>
> My program is able to interact with a remote R session, i.e. the session
> will start on a different machine than the one TeXmacs runs on. Luckily, it
> is also possible to detect when R waits for a prompt in a remote session by
> doing these ugly terminal hacks.
>
> In some cases the R prompt won't be a prompt for another command, but
> instead, R is just waiting for user input, or for completion of the previous
> input.
>
> Now, my remaining question is this:
> When I run R remotely, by emulating a terminal, and interacting with R in
> command line mode, AND
> when at the same time R is not waiting for a command, but instead for some
> other kind of user interaction, my interface can't send to R a request to
> execute the code to complete a certain string.
> (I.e. call the function t.tab.complete that I attached below).
>
> If I understand correctly, one solution is to write a replacement input
> loop, so that R will call my ReadConsole() from time to time, and while I'm
> inside that function, I could call R functions to provide tab completion.
>
> In that case, for remote sessions, I would have to compile on the remote
> computer this alternative R input loop, and I would have to have one for
> every version of R that a user might want to run on the remote machine (the
> machine I am currently working with remotely has 11 versions of R
> installed...). I was wondering if there is still a way to avoid that, and
> interact with the regular input loop, or maybe it is possible to load an
> alternative input loop from a package/library inside an already running
> regular R interface?
> I would like the user to have to do as little as possible in terms of
> installing additional programs on a remote machine.
>
> Thanks,
> I'm not sure if this was the type of additional information you meant...
> Michael
>
> Here is my tab completion routine, ("\2" and "\5" are the codes for TeXmacs
> for a start and a stop of blocks. (basically like brackets) ).
> -----
> t.tab.comp<-function(s,curs)
>    {
>      rc.settings(help=F) #This is because of a bug in matchAvailableTopics in
> package utils
>      rc.settings(file=T)
>
>      utils:::.assignLinebuffer(substr(s,1,curs))
>      utils:::.assignEnd(nchar(s))
>      utils:::.guessTokenFromLine()
>      utils:::.completeToken()
>      l=utils:::.retrieveCompletions()
>      l=sapply(l,function(x) {
>        substr(x, nchar(utils:::.CompletionEnv[["token"]])+1,nchar(x) )
>      } )
>      i=grep("=$",l)
>      if( (length(l[-i])>  10)&  (length(i)>0 ) )
>      l=c(l[i])
>      s3=utils:::.CompletionEnv[["token"]]
>      s3=gsub("\"","\\\\\"",s3)
>      deb.l<<- l
>
>      cat("\2scheme:(tuple \"",s3,"\"",sep="") ;
>      cat(" \"")
>      if( length(l)>  0 )
>      {
>        cat(l,sep="\" \"")
>      }
>      else
>      {
>        #cat(s)
>        cat("\"\"")
>      }
>      cat("\"")
>      cat(")\5")
>
>    ----
>