Stop packages and datasets to be loaded on startup.

Hi.

I would like to know how to start an embedded R session, and avoid datasets and the standard library packages to be loaded on startup.

I've been looking at littler's code (so this is partly a question to Dirk Eddelbuettel...):

       /* We don't require() default packages upon startup; rather, we
        * set up delayedAssign's instead. see autoloads().
        */
       if (setenv("R_DEFAULT_PACKAGES","NULL",1) != 0){
               perror("ERROR: couldn't set/replace R_DEFAULT_PACKAGES");
               exit(1);
       }

The code above happens before Rf_initEmbeddedR in littler.

So I gather that just setting R_DEFAULT_PACKAGES to NULL should be OK. But then, what is the rather complicated stuff in the autoload() function in littler.c for?

And concerning datasets, how do you avoid loading them?

So I gather that just setting R_DEFAULT_PACKAGES to NULL should be OK. But then, what is the rather complicated stuff in the autoload() function in littler.c for?

And concerning datasets, how do you avoid loading them?

Setting R_DEFAULT_PACKAGES to NULL makes sure that default packages are not loaded. Note that "datasets" are not loaded at all -- you can load the datasets package which will make them available, but they are not really "loaded". The minimal setup is simply

R_DEFAULT_PACKAGES=NULL R --vanilla

However, it's your responsibility to load any packages that your code needs in that case.

Cheers,
Simon

yziquel at seldon:~$ ocaml
        Objective Caml version 3.11.1

# #use "topfind";;
- : unit = ()
Findlib has been successfully loaded. Additional directives:
  #require "package";;      to load a package
  #list;;                   to list the available packages
  #camlp4o;;                to load camlp4 (standard syntax)
  #camlp4r;;                to load camlp4 (revised syntax)
  #predicates "p,q,...";;   to set these predicates
  Topfind.reset();;         to force that packages will be reloaded
  #thread;;                 to enable threads

- : unit = ()
# #require "R.interpreter";;
/usr/lib/ocaml/unix.cma: loaded
/usr/lib/ocaml/str.cma: loaded
/usr/lib/ocaml/calendar: added to search path
/usr/lib/ocaml/calendar/calendarLib.cma: loaded
/usr/lib/ocaml/R: added to search path
/usr/lib/ocaml/R/r.cma: loaded
/usr/lib/ocaml/R/oCamlR.cmo: loaded
# R.strings_of_t (R.eval_string "loadedNamespaces()");;
- : string list = ["base"]
# R.strings_of_t (R.eval_string "search()");;
- : string list = [".GlobalEnv"; "Autoloads"; "package:base"]
#

| I've been looking at littler's code (so this is partly a question to 
| Dirk Eddelbuettel...):

Credit where credit is due. Littler is a project by Jeff Horner and myself
building on Jeff's work with rapache which is another industry-strength use
of embedding of the R engine.

| >         /* We don't require() default packages upon startup; rather, we
| >          * set up delayedAssign's instead. see autoloads().
| >          */
| >         if (setenv("R_DEFAULT_PACKAGES","NULL",1) != 0){
| >                 perror("ERROR: couldn't set/replace R_DEFAULT_PACKAGES");
| >                 exit(1);
| >         }
| 
| The code above happens before Rf_initEmbeddedR in littler.
| 
| So I gather that just setting R_DEFAULT_PACKAGES to NULL should be OK. 

Yes, see Simon's reply.

| But then, what is the rather complicated stuff in the autoload() 
| function in littler.c for?

We load what we need for littler. And nothing more. See autoloads.h which is
autogenerated by make using autoloads.R during the build process.

On-demand Loading of Packages

Description:

     ?autoload? creates a promise-to-evaluate ?autoloader? and stores
     it with name ?name? in ?.AutoloadEnv? environment.  When R
     attempts to evaluate ?name?, ?autoloader? is run, the package is
     loaded and ?name? is re-evaluated in the new package's
     environment.  The result is that R behaves as if ?file? was loaded
     but it does not occupy memory.

     ?.Autoloaded? contains the names of the packages for which
     autoloading has been promised.

| And concerning datasets, how do you avoid loading them?

Maybe by not loading the datasets package?  But note that packages may fail
their examples.

Simon Urbanek a ?crit :

So I gather that just setting R_DEFAULT_PACKAGES to NULL should be OK. But then, what is the rather complicated stuff in the autoload() function in littler.c for?

And concerning datasets, how do you avoid loading them?

Setting R_DEFAULT_PACKAGES to NULL makes sure that default packages are not loaded. Note that "datasets" are not loaded at all -- you can load the datasets package which will make them available, but they are not really "loaded". The minimal setup is simply
R_DEFAULT_PACKAGES=NULL R --vanilla
However, it's your responsibility to load any packages that your code needs in that case.
Cheers,
Simon

OK. Thanks. Just one more question concerning package base. It seems that setting R_DEFAULT_PACKAGES to NULL doesn't remove the base package. Is the base package removable?