On 24/06/2011 22:04, John Chambers wrote:
Strictly speaking, that is not meaningful. A class (like any R
object) is uniquely referenced by a name *and an environment*. The
name of a package can be used to construct the environment, but your
"character slot" won't identify a class reliably unless the character
string has a "package" attribute.
Look at class(x), for example, from an object from one of these
classes. It will have a "package" attribute identifying the package.
The character string with the package attribute is what you should be
storing in the slot (or else store the class definition---takes more
space but is slightly more efficient).
Thank you for this clarification, I will make my factory method for the
relevant class add the package attribute to the slot.
Storing the class would require recreating the object if the user makes
changes in the class definition. These objects are meant to be used when
developing new algorithms. In this context one expects the user to do
multiple tries and modifications, and I want to ease the process, by
using dynamic links to classes (a character slot) rather than static
links (result of getClass).
However, this does not explain why .onLoad does not find the class while
.onAttach finds it, does it?
Is .onLoad evaluated outside the namespace environment, while .onAttach
is evaluated within the namespace?
Thank you.
Renaud
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