[R] change function scope?

[Duncan Murdoch]

On 11-05-26 5:09 PM, James McCreight wrote:
> I'm still getting used to R's scoping. I've run into the following situation
>
> value=0
> thefunction<- function() print( value )
> somefunction<- function() { value=99; thefunction() }
> somefunction()
>
> now, I understand that somefunction() returns 0 because thefunction() was
> defined with value=0 in its parent envrionment, it dosent look at all in the
> environment of somefunction. My question is can I re-scope thefunction in
> the somefunction environment?? (So that somefunction() returns 99). I've
> tried various uses of eval() and assign() with their keywords in the
> definition of somefunction and have had no luck at all.
>
> I do see that i could define thefunction in some external file and source it
> inside somefunction, but that seems clumsy.
>

Yes, you've been told how to do it:  but you almost certainly shouldn't. 
  Think of functions as functions, not as macros.  Changing the 
environment of a function is like editing it.  Would you ask how to 
change the body of thefunction from within somefunction?  You can in R, 
but you shouldn't.

Duncan Murdoch