Dirk Eddelbuettel a écrit :
| 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.
No harm intended.
| > /* 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.
I had a look at help(Autoload):
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.
But I do not understand a few things about it:
-1- If I do not want autoloading, I should simply remove the
.AutoloadEnv environment? Or keep it empty?
-2- How is this environment populated at startup? How can I ensure that
it be empty?
| And concerning datasets, how do you avoid loading them?
Maybe by not loading the datasets package? But note that packages may fail
their examples.
Thanks a lot.
--
Guillaume Yziquel
http://yziquel.homelinux.org/
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