[R] updating a helper function in a R package

[Tao Shi]

Hi list,

Sorry for the vague title, but here is the scenario.  

I’m writing an R package, let’s say, ‘pkg1’, which contains 3 functions: f1, f2, f3.  f2 and f3 are helper functions for f1, i.e. f1 calls f2 which in turn calls f3.

f1 <- function(…) {
	….
	f2()
	…
}

f2 <- function(…){
	…
	f3(…)
	…
}

f3 <- function(...){
       ....
}

Then, I wrote a new version of f3 and I want to test it.  With the old version of ‘pkg1’ already loaded into my R session, I tried just copy-and-paste the new ‘f3’ to R console and hope f1 will pick the new ‘f3’ up.  It obviously didn’t work.  I know it’s b/c the new f3 and old f3 are in different environments and when f1 is called, only old f3 is used.  Then I tried to change the environment of new f3 to the same as the old f3's by calling:

environment(f3) <- environment(pkg1:::f3)

but it wasn't working either.

So,  
1)	Could somebody help me to put all these into perspectives?
2)	Is there an easier way to update f3 without rebuilding the package? (by that I mean, writing the new version of f3 in a way that I only need to copy-and-paste to R console and I’m good to go.  I know it’s kind of stupid but I’m curious to know) 

I'm using R-2.5.1, on WinXP.

Many thanks,

…Tao


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