[R] Understanding contents of packages

[Ista Zahn]

Hi Dennis,

Out of curiosity, what is the purpose of this exercise?

Best,
Ista

On Thu, Apr 11, 2013 at 2:34 PM, Fisher Dennis <fisher at plessthan.com> wrote:
> Colleagues
>
> During the transition to R3.0.0 (OS X), one of the packages that I used -- SASxport -- did not work until I used the "type=source" option in install.packages.
>
> This led to an adventure:
>         1.  I downloaded the package source:            SASxport_1.2.4.tar.gz
>         2.  in the SASxport/R folder, I found all the functions that are part of the package.
> I became interested in whether I could "source" these functions directly into R and re-create the functionality of the package without installing/"require"ing the package.
>
> This started with some success until I encountered one problem that I could not overcome.
> When I executed the function write.xport, I received the following error message:
>         Error in .C("fill_file_header", cDate = xport.dateFMT(cDate), mDate = xport.dateFMT(mDate), :
>           C symbol name "fill_file_header" not in load table
>
> This appears to be coming from the following line of code in write.xport:
>         out(xport.file.header( cDate = cDate, sasVer = sasVer, osType = osType))
> The problem appears to be in
>         xport.file.header
> for which the entire code is:
>
> xport.file.header <-
>   function(cDate=Sys.time(), mDate=cDate, sasVer="7.00", osType="Unknown" )
>   {
>     .C("fill_file_header",
>        cDate = xport.dateFMT(cDate),           # Creation date
>        mDate = xport.dateFMT(mDate),           # Modification date
>        sasVer = toupper(as.character(sasVer)), # SAS version number
>        osType = as.character(osType) # Operating System (can include lowercase)
>        )
>
>     .Call("getRawBuffer", PACKAGE="SASxport")
>
>   }
>
> Of note, I commented out the line:
>         .Call("getRawBuffer", PACKAGE="SASxport")
> and the same error occurred (I did not expect this is solve the problem).
>
> I then looked in SASxport/src and found three files (which appear to be coded in C):
>         init.c
>         writeSAS.c
>         writeSAS.h
> that refer to "fill_file_header"
>
> I suspect that these files need to be accessed in some manner in order for xport.file.header and other functions to work correctly.
> The question is how do I access these files:
>         Do I "source" them in some manner?
>         Put them in a particular location where they are sourced automatically?
>         I tried dyn.load but that does not appear to be the correct approach.
>
> Any help would be greatly appreciated.
>
> Thanks
>
> Dennis
>
>
> Dennis Fisher MD
> P < (The "P Less Than" Company)
> Phone: 1-866-PLessThan (1-866-753-7784)
> Fax: 1-866-PLessThan (1-866-753-7784)
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>
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