Set a functions environment to that of the calling environment (parent.frame) from within function

Question

I am still struggling with R scoping and environments. I would like to be able to construct simple helper functions that get called from my 'main' functions that can directly reference all the variables within those main functions - but I don't want to have to define the helper functions within each of my main functions.

helpFunction<-function(){
#can I add a line here to alter the environment of this helper function to that of the calling function?
return(importantVar1+1)
}

mainFunction<-function(importantVar1){
return(helpFunction())
}

mainFunction(importantVar1=3) #so this should output 4

Answer 1

If you declare each of your functions to be used with dynamic scoping at the beginning of mainfunction as shown in the example below it will work. Using helpFunction defined in the question:

mainfunction <- function(importantVar1) {

    # declare each of your functions to be used with dynamic scoping like this:
    environment(helpFunction) <- environment()

    helpFunction()
}

mainfunction(importantVar1=3)

The source of the helper functions themselves does not need to be modified.

By the way you might want to look into Reference Classes or the proto package since it seems as if you are trying to do object oriented programming through the back door.