Stop an R program without error

Question

Is there any way to stop an R program without error?

For example I have a big source, defining several functions and after it there are some calls to the functions.

Answer 1

Just return something at the line you want to quit the function:

f <- function(x, dry=F) { 
   message("hi1")
   if (dry) return(x)
   message("hi2")
   x <- 2*x 
}
y1 <- f(2) # = 4 hi1 hi2
y2 <- f(2, dry=T) # = 2 hi1