R-alpha: A Couple of Queries

Luke Tierney luke@stat.umn.edu
Mon, 19 May 1997 20:09:01 -0500 (CDT)

Ross Ihaka wrote:
> This is what I had in mind.  The functions in the library (and those
> exported) could see all functions and data in the library, but only the
> exported objects would be visible globally.  Of course, R scoping
> can be used to provide this kind privacy, but you have to think
> about setting up the libraries more carefully.

Is your design consistent with (maybe not now but later) allowing a
library to specify a static search path component for code defined in
it that comes before entries added dynamically at runtime? THis would
allow a "uses" specification where a library definition specifies
other libraries it uses and can be sure these will be used and not
whatever happens to be attached earlier on the search path. Among
other things, this might allow something like

	LIBRARY: survival
	EXPORTS: coxph, ...
	USES: S.compatibility, S.syntax, ...
	.... insert Terry's latest code ...

So when the library is loaded, S syntax is used (if it differs from
R's) and when the body of a function like coxph is executed,
definitions from the S compatibility library will be called instead of
standard R ones (if they differ).  This would make it easier for R to
go its own way when it that seems appropriate without losing the
ability to use S code.

Luke Tierney
University of Minnesota                      Phone:           612-625-7843
School of Statistics                         Fax:             612-624-8868
206 Church Street                            email:      luke@stat.umn.edu
Minneapolis, MN 55455 USA                    WWW:  http://www.stat.umn.edu
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