[R] readline() for passwords?

[Barry Rowlingson]

Ulf Mehlig wrote:

> I am using RODBC to access a password-protected database. Is there a
> possibility to prevent that the password appears on the screen when
> issuing the odbcConnect() command? I thought of something like
> readline() without echo. I guess that a getpass()-based solution
> wouldn't work for ESS/Emacs, anyway, would it?

tk has a way of doing this, so you can build a function that uses the 
tcltk package. Something like:

getPassword <- function(){
   require(tcltk)
   tt <- tktoplevel()
   pass=tclVar("")
   label.widget <- tklabel(tt, text="Enter Password")
   password.widget <-  tkentry(tt,show="*",textvariable=pass)
   ok <- tkbutton(tt,text="Ok",command=function()tkdestroy(tt))
   tkpack(label.widget, password.widget,ok)
   tkwait.window(tt)
   return(tclvalue(pass))
}

The vital part here is the 'show="*"' option in the tkentry widget.

Of course this is no use if you aren't in a graphical environment at the 
time.

Barry