[R] How to specify search order for require()

[Frank E Harrell Jr]

Thank you Thomas Lumley and Luke Tierney for your responses.  I think in the long run Luke's approach is a good one.  For now I decided to be expeditious by redefining library to take a pos= argument.  All that's needed is to pass this to the attach( ) inside library, which I hope R-core will add to the library function.  I also modified require (calling it requirePos) to implement a pos argument.  My usage of these is as follows:

library(Hmisc)    
# attaches Hmisc library, redefine library, define requirePos

library(Design, pos=2)

.First.lib in Design:

.First.lib <- function(lib, pkg) {
  library.dynam("Design", pkg, lib)
  requirePos('Hmisc',pos=2)
  requirePos('survival',pos=3)
  p <- .packages()
  if(match('Design',p) > match('survival',p))
    warning('By not specifying library(Design,pos=2), functions in the\nsurvival package such as survfit will override those in Design.')
  invisible()
}

I realize that overrides are to be avoided but there are a few I couldn't get around easily.  I hope that library and require are enhanced with pos=.

Frank

On Fri, 12 Apr 2002 12:06:31 -0400
Frank E Harrell Jr <fharrell at virginia.edu> wrote:

> In a .First.lib I want to issue two require()s to insure that two other packages are loaded.  But I want the package being loaded by .First.lib using library.dynam("mypackage",pkb,lib) to be higher in the search order than the two required packages, because I want to have a couple of functions from the two required packages overridden.  What is the best way to do that?  Thanks in advance -Frank
> 
> -- 
> Frank E Harrell Jr              Prof. of Biostatistics & Statistics
> Div. of Biostatistics & Epidem. Dept. of Health Evaluation Sciences
> U. Virginia School of Medicine  http://hesweb1.med.virginia.edu/biostat
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-- 
Frank E Harrell Jr              Prof. of Biostatistics & Statistics
Div. of Biostatistics & Epidem. Dept. of Health Evaluation Sciences
U. Virginia School of Medicine  http://hesweb1.med.virginia.edu/biostat
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r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
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