R help - Feb 2013 - Building a Package & using gWidgets

Hi,

For the past few months I've been building a simulation in R I hope to
package. It consists of two usable functions, and many internal ones which one
of the two usable functions call while looping, to perform the stages of
simulation.

A simple conceptual example is:

# Abstract representation 1st Usable function, generates object containing
settings for simulation.
settings <- function(){
  matrix(c(1:4),nrow=2,ncol=2)
}

# Abstract representation of one of many internal functions, does some action in
simulation.
int.func <- function(x){
  out <- x*2
  return(out)
}

# Abstract representation of second usable function, takes settings &
invokes internal functions generates results & saves as R object files.
sim.func <- function(x){
  ans <- int.func(x)
  ans2 <- ans-2
  save(ans2, file="outtest")
}

With my package so far, using it is done like so after loading and attaching the
package with library():

INPUT <- settings()
fix(settings) # If you want to change from the defaults.
sim.func(INPUT)

Nothing needs returning from the simulation because it gets saved as an object
to be read in afterwards.

Now I'd like it to have a simple GUI which can be used in conjunction with
command line - think Rcmdr but much more simple, to allow my co-workes who have
never touched R to use it.
The gui needs to be able to edit the settings - like with the fix command above,
to save a settings object to file, and to read in setting from an object file.
I've built this with gWidgets:

gui <- function(){
  INPUT <- matrix(c(1:4),nrow=2,ncol=2)

  mainwin <- gwindow("MainWindow")

  button1 <- gbutton("Edit Settings", cont=mainwin, handler        
function(h,...){
                         fix(INPUT)
                         print("Settings Edited")
                       })

  button2 <- gbutton("RUN", cont=mainwin, handler                  
function(h,...){
                         sim.func(INPUT)
                         print("The run is done")
                       })

  savebutton <- gbutton("Write Settings to File",cont=mainwin,
handler                          function(h,...){
                            setfilename <- ginput("Please enter the
filename")
                            save(INPUT, file=setfilename)
                          })

  loadutton <- gbutton("Load Settings from File", cont=mainwin,
                   handler=function(h,...){
                     fname <- gfile(test="Choose a file",
                                    type="open",
                                    action="print",
                                    handler                                     
function(h,...){
                                        do.call(h$action, list(h$file))
                                      }
                     )
                     load(fname)})
}

Note the job of the settings function from before is now done by the first line
of this gui function.
I add this to the same R file as the three functions above, add 'gui' to
the namespace as an export, set gWidgets stuff as imports, and rebuild, then I
library() the package and do gui().
The interface shows up. However I have a few issues:
The gui shows up fine, but if I click button1 to edit settings through
fix(INPUT), then change the values, close the editor and click the button again
to see if the changes have persisted and been stored in INPUT, they have not.
Same goes for reading in an object, it does not overwrite the INPUT object
generated by default in the first line of function gui().

I think this has something to do with environments of functions but I'm not
too sure. In the gui-less version of my package, the user generates the object
containing settings, which is in workspace and feeds it to the simulation
function as an argument. However since with the gui version, everything is run
inside the function gui() and gWidgets handlers makes use of functions(h,...) I
can't help but feel as if environments are the issue here. It's odd that
when clicking on button 1, it will find INPUT from the gui() environment, but
won't make the changes back there.

Can anybody help out with this and suggest what it is I need to do?

Apologies for a long email, but I've tried to explain clearly. Code is
reproducible, as is the issue, just by having library(gWidgets, gWidgetstcltk)
and copying and pasting code. The abstract example I've provided faithfully
reproduces the same issues I have with my proper simulation functions so if I
can't get it working, I won't get the real thing working.

Thanks,

Ben W.
UEA
The Sainsbury Laboratory.

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