[R] coordinates of mouse position

[solares@unsl.edu.ar]

HI, I need known the position of mouse, but i not know how obtain the
parameter %X used in tcl. the script in Tcl is:

set w .probe
catch {destroy $w}
toplevel $w
proc Captura_Datos { ancho alto } {
puts "El ancho es $ancho"
puts "El alto es $alto"
} bind $w <Configure> "Captura_Datos %X %Y"

In R
w<-tktoplevel()
f<-function(a,b)^`
print(a)
print(b)

tkbind(w,"<Configure>",f(%X,%Y))
Not works. How to do this? thanks Ruben