#
#  Global vs local variables
#    how to use "<<-" to set global variable and functions
#    7/11/2011
#
#===========================================================

if (stage==2) {

  a <- function(x) {
    b <- 3
    return( b*x)
  }

  a(5)    # use function above
  b       # can't find


  #--- set global variable with "<<-" -----
  a <- function(x) {
    b <<- 3
    return( b*x)
  }

  a(5)    # use function above
  b       # now this is 3

  #--- now set global function ---
  k <- function(x) {
    b <<- function(x) print(x*20)
    return(5*x)
  }

  k(5)
  b
  b(3)

}