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Two tcltk questions and Re: [R] tcltk package functionality

2 messages · Peter Wolf, Peter Dalgaard

Original
Peter Wolf
# 
Sorry, for my mail from last night contains no subject.
Therefore, I send it again and two tcltk questions are appended.

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Prasad wrote:

            

      
      
      
    

        
To stop the evaluation of a function until a specific tcltk action is done
you have to use the tk-function tkwait.variable().
The following function -- a simple modification of Prasad's
tcltktst function -- shows an example:

tcltk.test <- function(x1=1:10, x2=10:1) {
 library("tcltk")
# define first toplevel-widget
 tt           <- tktoplevel()
 tktitle(tt)  <- "Diagnostics"
 label.widget <- tklabel(tt, text="Choose data for plot!")
 rbut.wid1    <- tkradiobutton(tt, text="x1", value="0", variable="choice")
 rbut.wid2    <- tkradiobutton(tt, text="x2", value="1", variable="choice")
 but.done     <- tkbutton(tt, text="FINISHED", command=function(){
                                                         tclvar$done <- "T"
                                                         tkdestroy(tt)
                                                       } )
 tkpack(label.widget, rbut.wid1, rbut.wid2, but.done)
# wait until FINISHED is pressed
 tclvar$choice <- "0"
 tkwait.variable("done")
# plot x1 or x2
 if(tclvar$choice == "0") x <- x1
 if(tclvar$choice == "1") x <- x2
 if(is.null(names(x))) names(x) <- x
 plot(x)
# define second toplevel widget
 tt2          <- tktoplevel()
 tktitle(tt2) <- "Action"
 but.wid21    <- tkbutton(tt2, text="print summary",
                          command=function()print(summary(x)))
 but.wid22    <- tkbutton(tt2, text="identify outlier",
                          command=function()identify(x))
 but.wid23    <- tkbutton(tt2, text="exit", command=function(){
                                                      tclvar$done<-"T"
                                                      tkdestroy(tt2)
                                                    } )
 tkpack(but.wid21, but.wid22, but.wid23)
# wait until exit is pressed
 tclvar$done <- "F"
 tkwait.variable("done")
}

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Here are another two tcltk question:

1. I want to add a scrollbar along the right side of a text widget. This can be
   achieved by .Tk.ID(). Is there a way to avoid to call .Tk.ID ---
   perhaps by using tkyview?

   tk.test1 <- function(nmax=3){
     library("tcltk")
     tl         <- tktoplevel()
     tl.text    <- tktext(tl)
     tl.yscroll <- tkscrollbar(tl)
     tkconfigure(tl.text,   yscrollcommand=paste(.Tk.ID(tl.yscroll),"set"  ))
     tkconfigure(tl.yscroll,       command=paste(.Tk.ID(tl.text),   "yview"))
     tkpack(tl.text, tl.yscroll, side="left", fill="y")
     tkpack(tkbutton(tl, text="exit", command=function()tclvar$done<-"T"))
     tclvar$done <- "F"; tkwait.variable("done")
     tkdestroy(tl)
   }


2. If I try to insert a text containing an unequal number of "{" and "}"
   brackets tkinsert stops with the error message:

     Error in .Tcl(.Tcl.args(...)) : [tcl] extra characters after close-brace.

   How can I change this behavior?

   tk.test2 <- function(nmax=3){
     library("tcltk")
     tl         <- tktoplevel()
     tl.text    <- tktext(tl)
     tkpack(tl.text)
     for(i in 1:nmax){
       cat("input text? "); input.text<-readline()
       tkinsert(tl.text,"0.0",input.text)
     }
     tkdestroy(tl)
   }

--------------------------------------------------------------------------

Version information:
platform hppa2.0-hp-hpux10.20
major    1
minor    1.0
year     2000
month    June
day      15

--------------------------------------------------------------------------

Peter Wolf

R + tktcl is a very fantastic combination! Thanks to all of the Core team!
--------------------------------------------------------------------------
Hans Peter Wolf                       pwolf at wiwi.uni-bielefeld.de
Fak. f. Wiwi.
Uni Bielefeld
33615 Bielefeld
Germany
-------------------------------------------------------------------------

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      Peter Dalgaard
    

    

      
      #
    

  


  

      
Peter Wolf <pwolf at wiwi.uni-bielefeld.de> writes:

            

      
      
      
    

        
One problem with this stuff is that the users seem to be quickly
becoming more proficient than the programmer... 

The first one is avoidable by a construction like

     tkconfigure(tl.text,
       yscrollcommand=function(...)tkset(tl.yscroll,..2,..3))
 
I.e. you get a callback to R instead. The yscrollcommand option works
by sticking arguments at the end of what the .Tcl.callback generates
for the function, so the callback is actually called with arguments
(%...,x,y) and you need to extract (x,y) by the above kludge (or
something equally kludgy). Ick.

Similarly, one can do 
     tkconfigure(tl.yscroll,
       command=function(...)tkyview(tl.yscroll,..2,..3))

*but* there's a varying number of arguments in this case, so it only
works on the slider of the scrollbar, not the arrowheads at the end.
You need to apply an alternate kludge to pass all arguments except the
first on to tkyview (exercise for the reader...)

Alternatively tell me how to avoid producing that "%..." argument on
callbacks and command=function(...)tkyview(tl.yscroll,...) should
work. I suspect that it might be easy.

            

      
      
      
    

        
By fixing the bug ;) This has been waiting to happen. The quoting
mechanisms of Tcl makes it impossible to get an unbalanced set of
braces into a {...}-delimited string and this is what the .Tcl
interface is producing. So one really needs to use "..." delimiting
with the entire morass of special character escapes. This is due to
sheer laziness on my part (or slightly nicer put: my mind was
focused elsewhere at the time).