[R] Question: write an R script with help information available to the user

[Gabor Grothendieck]

On Sat, Feb 2, 2013 at 6:31 PM, Chee Chen <chen418 at purdue.edu> wrote:
> Dear All,
>
> I would like to ask a question on how to incorporate into an R script help information for the user. I vaguely recall that I saw some instructions on an R manual, but am not able to figure them out. Hereunder is the basic setting:
>
> 1.  I finished writing an R script, my_script.r, that is a function (the function is named "my_func") for a statistical procedure. This means that the user only needs to: source("directory_of_script\my_script.r"), then run, my_func(arg1, arg2, ..), to execute the procedure.
>
> 2. I would like to add some lines into "my_script.r", so that a user can get information on this file and function by using "?my_func"
>


You may wish to create a package from your script; however, if you
would prefer not then a workaround would be to redefine the ? function
in your script to provide some help.  For example if you had this line
in your script:

`?` <- function(...) if (match.call()[[2]] == "mytopic")
cat("whatever\n") else help(...)

then this would work:

> ?mytopic
whatever
> ?dim

where the last line launches normal help.  If you wish to display a
file rather than cat strings to the console then use: file.show


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