R help - Feb 2010 - How to source files from a search path?

Suppose some environment variable (say MY_R_INC) has a number of
paths. I want to source some file relative to some path in $MY_R_INC
(just as #include in C++ does, which looks for header file in a number
of directories). I RSiteSearch'ed, but I don't find any function that
satisfies my need. Could somebody let me know if I overlooked
something?

1. Etiquette on this list is to sign posts with your real name.

2. Please use R's Help facilities (beyond RSiteSearch()) first before
posting:

?help.search

help.search("environment variable") 


Bert Gunter
Genentech Nonclinical Statistics

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On
Behalf Of blue sky
Sent: Friday, February 12, 2010 2:55 PM
To: r-help at stat.math.ethz.ch
Subject: [R] How to source files from a search path?

Suppose some environment variable (say MY_R_INC) has a number of
paths. I want to source some file relative to some path in $MY_R_INC
(just as #include in C++ does, which looks for header file in a number
of directories). I RSiteSearch'ed, but I don't find any function that
satisfies my need. Could somebody let me know if I overlooked
something?

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On Fri, Feb 12, 2010 at 6:11 PM, Don MacQueen <macq at llnl.gov>
wrote:
> Well, you still will need Sys.getenv() to get the value of the environment
> variable into R.
>
> Are you familiar with the function named list.files() ?
>
> This may do the job:
>
> ? source( list.files( Sys.getenv('SOMEENVVAR'),
pattern='myfilename') )
>
> But I haven't tested it.
This doesn't do what I want. Anyway, I made my own program. Let me
know if a function that does the same thing is available in some other
packages.

smart.source=function(partial_path) {
  source(full.path(partial_path))
}
full.path=function(partial_path) {
  found_rpath=base:::Find(
    function(p) {
      full_path=base:::file.path(p, partial_path)
      base:::file.exists(full_path)
    }
    , base:::unlist(base:::strsplit(base:::Sys.getenv('RPATH'),
':'))
    )

  if(is.null(found_rpath)) {
    stop(paste(partial_path, ' is not found in $RPATH', sep=''))
  } else {
    base:::file.path(found_rpath, partial_path)
  }
}


#shell environment variable
RPATH=/dir1:/dir2


I have the following R file, which is in /dir2.

$ cat main_test.R
f=function() {
  print('in f')
}


Then I can source the above file like the following.
> smart.source('smart.source/main_test.R')
> f()
[1] "in f"