circular holes in rectangular polygon

Jan Quets Jan.Quets at ua.ac.be writes:

I want to make a rectangular window with circular holes within.
I have tried and searched but not found a solution yet.

library(spatstat)
R <- owin(c(0,4),c(0,5))
O <- disc(radius=1, centre=c(2, 3))
W <- complement.owin(O, frame=R)
plot(W)