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assignInNamespace and new bindings

2 messages · Thomas Friedrichsmeier, Luke Tierney

Original
Thomas Friedrichsmeier
# 
Hi,
On Tuesday 31 May 2011, luke-tierney at uiowa.edu wrote:
sorry to insist, but I was hoping for a slightly more specific pointer. I'll 
try asking it another way:

Suppose I was using assignInNamespace() entirely bona fide, i.e. to develop and 
test patches with the intent to offer them to the package maintainer(s) for 
inclusion. What sort of gotchas should I be looking out for, specifically with 
respect to the compiler? Also, if the package that I'm trying to improve is a 
base package?

Regards
Thomas

P.S.: Just to let you know, why I do not feel too much ashamed or scared of 
changing things in other people's packages, here's (slighlty simplified) the 
pattern that I'm following:

backup <- original
replacement <- function() {
      call.my.hook()
      eval(body(backup))
}
formals(replacement) <- formals(backup)
environment(replacement) <- environment(backup)
assignInNamespace(...)

I know that leaves subtle differences beyond anything the compiler may be 
doing, such as in the sys.calls(). I am also pretty certain that these subtle 
differences are completely irrelevant *in those functions that I modify* this 
way. And I have a bunch of automated tests to make me sleep better, too.

Ok, and for a select few functions, my replacements are more "radical", such 
as for utils::savehistory(). But then, that is essentially non-functional in 
my use-case in its original incarnation, in the first place, so I'm not really 
scared of making things worse, there, either.
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Luke Tierney
#
On Wed, 1 Jun 2011, Thomas Friedrichsmeier wrote:

            

      
      
      
    

        
At the moment the main issue is that the assignment may not have any
effect on compiled code because the compiled code accesses the
finctionality known to be provided by these funcions in some more
direct way.  Examples are BUILTIN functions, which are called directly
through the internal table, and some functions that are simple
wrappers around .Internal calls where the compiled code in effect goes
directly to the .Internal call.  At the moment this applies only to
some functions in base packages but may in the future extend to other
packages.

Best,

luke