[R] tcltk table "validateCommand"

[Dalthorp, Daniel]

Yes, Peter's suggestion worked just right.

Here's an example that prints out the proposed cell content and will not
allow 'w' or '\n' to be entered into the table:

require(tcltk2)
tt<-tktoplevel(); tfr<-tkframe(tt); tkgrid(tfr)
tableData<-tclArray()

valChar<-function(S){
  print(S); flush.console()
  if (length(grep("\n",S))>0){ #
    return(tcl("expr", FALSE))
  } else if (length(grep("w",S))>0){ #
    return(tcl("expr", FALSE))
  } else {
    return(tcl("expr", TRUE))# but other kinds of space are not-->
error-checking if good value is added
  }
}

table1<-tk2table(tfr,
  rows = 1,cols = 1,
  variable = tableData,
  validate = T,
  vcmd = valChar
)

tcl(table1, "tag", "configure", "active", fg='black', bg='yellow')
tkgrid(table1)

# I believe when you define vcmd, it has the effect of reserving the %
arguments for their meanings as defined "in the manual"
# there's no need to think about the %'s thereafter.
# for some arguments, it doesn't seem to work as expected

-Dan


On Thu, Nov 17, 2016 at 3:12 PM, Cleber N.Borges via R-help <
r-help at r-project.org> wrote:

> Hi Dan
> Were you able to find a way to access the % S values ??
>
> Do you have any examples of how this works?
>
> Thank you for your attention.
> Cleber
>
>
> Em 25/01/2016 08:21, peter dalgaard escreveu:
> > It's been so long that I have forgotten how to get the package with the
> table widget installed on OSX, so I cannot check things for you. However,
> the canonical way to handle %S type arguments is to pass them as formal
> arguments to the callback, e.g.
> >
> >> .Tcl.callback(function(x,y)x+y)
> > [1] "R_call 0x7f9a34806ca0 %x %y"
> >
> > so I would assume that you should just define your
> >
> > CellValidation <- function(S){....}
> >
> > and then just access S as a variable inside the function.
> >
> > As far as I remember, this only works at entry completion, though. That
> does sort of make sense since not every prefix of a valid entry is valid
> ("1e-2" is a double, "1e-" is not). If you want to actually disable certain
> keys during entry, then you have a larger task on your hand.
> >
> > -pd
> >
> > On 22 Jan 2016, at 21:25 , Dalthorp, Daniel <ddalthorp at usgs.gov> wrote:
> >
> >> I'd like to allow users to edit data in tcltk tables and to use vcmd to
> >> validate data entry, e.g., not allowing non-numbers to be entered in
> >> numeric cells and not allowing '\n' to be entered in text cells.
> >>
> >> The problem is that I can't figure out how to "see" their data entry
> before
> >> it is entered, although it looks like %S can be somehow used in vcmd to
> get
> >> this information.
> >>
> >> Example: to disallow '\n' to be entered into a cell in an editable
> table:
> >>
> >> require(tcltk2)
> >> tt<-tktoplevel(); tfr<-tkframe(tt); tkgrid(tfr)
> >> tableData<-tclArray()
> >> tableData[[0,0]]<-"junk"
> >>
> >> CellValidation<-function(){
> >>
> >> ## http://www.tcl.tk/community/hobbs/tcl/capp/tkTable/tkTable.html
> says:
> >> ## *%S* For *ValidateCommand*, it is the potential new value of the cell
> >> being validated.
> >> ## which is exactly what I want, but I can't figure out how to do that.
> >> ## The following allows one bad character and then disallows further
> edits
> >>
> >>   testval<-tclvalue(tcl(table1,"curvalue"))
> >>
> >>   if (length(grep("\n",testval))>0)  return(tcl("expr", FALSE))  else
> >> return(tcl("expr", TRUE))
> >> }
> >>
> >> table1<<-tk2table(tfr,
> >>   rows=1,cols=1,
> >>   selectmode="extended",
> >>   variable=tableData,
> >>   validate=T,
> >>   vcmd=CellValidation
> >> )
> >>
> >> tcl(table1,"tag","configure", "active", fg='black',bg=colors()[411])
> >> tkgrid(table1)
> >>
> >> How can I get the %S value rather than the tcl(table1,"curvalue")?
> >>
> >> Much thanks for any help.
> >>
> >> -Dan
> >>
>
>
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-- 
Dan Dalthorp, PhD
USGS Forest and Rangeland Ecosystem Science Center
Forest Sciences Lab, Rm 189
3200 SW Jefferson Way
Corvallis, OR 97331
ph: 541-750-0953
ddalthorp at usgs.gov

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