[Rd] tkStartGUI fails under RW1091 (PR#7101)

[Philippe Grosjean]

Peter,

I think it should be possible to find a different solution to completelly
replace the R console by a Tcl/Tk console. The basic idea is to redirect
inputs and outputs of the R console in Rgui (SDI mode), and then hide R
console itself, thus without touching to the event loop(s). There are some
parts of such an implementation in John Fox's Rcmdr (redirection of output
to a Tcl/Tk window), and for the input (it is the way SciViews-R
communicates with external programs, but in this case, it is the Tcl/Tk
window that is hidden, not the original R console). Indeed, I just reworked
some code in the air for a simple code editor in tcltk (you present it in
your R-news paper about tcltk, isn't it).

Moreover, under Windows, the program that spawns a console can specify
different channels for input, output and error before spawning the console
(this works with Rterm only, of course). I use this in the SciViews R plug.
Indeed, R is driven by the R plug in --ess mode by redirecting input, output
and error to pipes. Under Windows NT/2000/XP, it is possible to specify
named pipes. Those are very convenient, because they can be handled as
files, including through the net. However, Windows 9X/Me/Millenium can only
connect to existing named pipes, but cannot create new ones. So, a solution
that works with any Windows platform should not use names pipes. This is a
different approach we could use. However, in this case, the solution would
be Windows-specific, I imagine. So, it means we would end up with a
different mechanisms under Unix/Linux, and under Windows.

Please, note that in both solutions, I have code capable to interrupt
calculation in R. I think this is a required feature, but it is not easy to
implement with all mechanisms.

I plan to replace totally my Visual Basic code by platform-independent code
in SciViews in the future. Using a Tcl/Tk console window may be a solution,
so I *may* further develop the concept. However, I am still looking at
potentially interesting alternatives, like James Wettenhall's wxPython, or
some improved Tcl/Tk solution based on your tcltk package, supplemented with
Tile and other supplemental widgets (I find the basic Tk widgets too limited
to implement the GUI I want to build with them).

Best,

Philippe

.......................................................<?}))><....
 ) ) ) ) )
( ( ( ( (   Prof. Philippe Grosjean
\  ___   )
 \/ECO\ (   Numerical Ecology of Aquatic Systems
 /\___/  )  Mons-Hainaut University, Pentagone
/ ___  /(   8, Av. du Champ de Mars, 7000 Mons, Belgium
 /NUM\/  )
 \___/\ (   phone: + 32.65.37.34.97, fax: + 32.65.37.33.12
       \ )  email: Philippe.Grosjean at umh.ac.be
 ) ) ) ) )  SciViews project coordinator (http://www.sciviews.org)
( ( ( ( (
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-----Original Message-----
From: r-devel-bounces at stat.math.ethz.ch
[mailto:r-devel-bounces at stat.math.ethz.ch]On Behalf Of Peter Dalgaard
Sent: Monday, 26 July, 2004 07:26
To: joehl at gmx.de
Cc: R-bugs at biostat.ku.dk; r-devel at stat.math.ethz.ch
Subject: Re: [Rd] tkStartGUI fails under RW1091 (PR#7101)


joehl at gmx.de writes:

> > library(tcltk)
> > tkStartGUI()
> Error in .C("RTcl_ActivateConsole", PACKAGE = "tcltk") :
>         C function name not in DLL for package tcltk

Yes. The source code for that function sits inside #ifndef Win32, so
it's hardly a bug, except that the documentation might be clearer (or
the R wrapper could throw a more explicit error). The whole thing is
quite experimental, on Unix too -- really just a proof of concept
thing at present.

The fundamental issue is that the way Tk takes over R's event loop
involves redefining ptr_R_ReadConsole and friends. This is quite
Unix-specific and the relevant declarations are lifted from
src/unix/devUI.h.

I don't know what the equivalent would be on Windows (a platform I use
reluctantly myself), and I kind of suspect that it can only work from
Rterm, not Rgui. Contributions from knowledgeable Windows programmers
would be welcome.

--
   O__  ---- Peter Dalgaard             Blegdamsvej 3
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907

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