[R] add checkbutton and the variable(wrong length of vector "b")

[solares@unsl.edu.ar]

Hello it wanted to add a boton of checkup in a menu, ¿How I do to create so 
many variables as  checkbutton?  I try with the code that continues, use a 
vector that is charged dynamicamente while I open files but the component 
of vector "b" is associates with a Tcl variable  and load 3 components 
(environment, value and pointer) I wanted alone to charge the value (0 done 
not select and 1 selected), and the length its wrong.  Good, here are the 
script so that they see it.  Thanks Ruben

library(tcltk)
vectPath<-c()
b<-c()
archivos<-function(){
          f<-tkcmd("tk_getOpenFile")
          temparch<-tclvalue(f)
          assign("vectPath",c(vectPath,temparch),.GlobalEnv)
          temp<-0
          assign("b",c(b,temp),.GlobalEnv) #charge the variable for the 
checkbutton
          cant<-length(vectPath)
          j<-vectPath[cant]                  
          tkadd(m, "check", label=j, variable=b[cant]) #add the variable
}

ver<-function(){
     i<-1 
     while (i<=length(b)) { #the length of b is wrong!!
     print(tclvalue(b[i]))
     i<-i+1
     }
}

borra<-function(){
	 assign("vectPath",c(),.GlobalEnv)
	 assign("b",c(),.GlobalEnv)	 
     tkdelete(m,"0","end")
}
tt <- tktoplevel()
tkpack(mb <- tkmenubutton(tt, text="Datos"))
m <- tkmenu(mb,tearoff=FALSE) 
tkconfigure(mb,menu=m)
b<-tkbutton(tt,text="abrir",command=function()archivos())
tkpack(b)
b3<-tkbutton(tt,text="ver",command=function()ver())
tkpack(b3)
b4<-tkbutton(tt,text="Borrar",command=function()borra())
tkpack(b4)