move up a frame, debug R environment

Question

When debugging a function, I would like to move up to the parent frame and look at some variables there. How do I do this?

Here is a sample:

f <- fun         


        

Answer 1

Just call on.exit(browser()) when browsing f's body and you'll return back to it after you're done with g()

See output copied from the console below :

> f <- function() {
+   x <-1
+   g(x+1)
+ }
> g <- function(z) {
+   y = z+2
+   return(y)
+ }
> debug("f")
> debug("g")
> f()
debugging in: f()
debug at #1: {
    x <- 1
    g(x + 1)
}
Browse[2]> on.exit(browser()) # browser() will be run in this environment just before we exit
Browse[2]> 
debug at #2: x <- 1
Browse[2]> 
debug at #3: g(x + 1)
Browse[2]> 
debugging in: g(x + 1)
debug at #1: {
    y = z + 2
    return(y)
}
Browse[3]> 
debug at #2: y = z + 2
Browse[3]> 
debug at #3: return(y)
Browse[3]> 
exiting from: g(x + 1)
Browse[2]> x # we're back to f so we can investigate x
[1] 1
Browse[2]> 
exiting from: f()
[1] 4