[R-pkg-devel] if statements in NAMESPACE file

[Jeff Newmiller]

What if you are on Windows but running R at the command prompt, or via cygwin, or in the console window of RStudio?

This seems unstable to me.

On September 30, 2021 11:52:16 AM PDT, Andrew Simmons <akwsimmo using gmail.com> wrote:
>Hello,
>
>
>I'm updating my package 'this.path' which is supposed to retrieve the
>absolute path of the executing script when called. It's similar to 'here',
>except that 'here' constructs paths relative to a project directory,
>whereas 'this.path' constructs paths relative to script directories. I was
>updating the section where I retrieve the executing script's path while
>running from a script open in Rgui for Windows, and I needed
>utils::getWindowsHandles to do such a thing. But utils::getWindowsHandles
>is a Windows only function, I
>would imagine that 'utils' contains a similar line of code as above:
>
>
>if (.Platform$OS.type == "windows")
>    getWindowsHandles <- function() ...
>
>
>and then in the NAMESPACE:
>
>
>if (.Platform$OS.type == "windows")
>    export(getWindowsHandles)
>
>
>so I'd like to change my code to getWindowsHandles and import
>getWindowsHandles from utils, but I can only do that on Windows, and so the
>conditional importing should work for me. At no point does my function
>mis-behave because of a attempting to use a function that isn't exported on
>that platform, because within the function it only uses getWindowsHandles
>if the OS is Windows.
>
>
>On Thu, Sep 30, 2021 at 11:01 AM Mark Miller <mark.roman.miller using gmail.com>
>wrote:
>
>> Returning to the original question, if it's helpful: I'd like to know what
>> constraints led to considering an export only available on Windows, and see
>> if we can suggest some other designs. It'd be good to keep the user's
>> mental model abstracted from the platform they're working on. There are
>> often unavoidable differences due to platform, but usually they're handled
>> with warnings and errors rather than selective exports.
>>
>> On Thu, Sep 30, 2021 at 3:40 AM Berry Boessenkool <
>> berryboessenkool using hotmail.com> wrote:
>>
>> >
>> > One of the very best fortunes nominations!
>> >
>> > [...]
>> >
>> >   I suspect something like
>> >
>> >    if (stats::runif(1) > 0.5) export(someFunction)
>> >
>> > would work too, for a particularly frustrating experience for your
>> > users.  It would mean half the installs export the function, and half
>> > don't.
>> >
>> > Duncan Murdoch
>> >
>> >
>> >         [[alternative HTML version deleted]]
>> >
>> > ______________________________________________
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>> > https://stat.ethz.ch/mailman/listinfo/r-package-devel
>> >
>>
>>         [[alternative HTML version deleted]]
>>
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>
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>
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-- 
Sent from my phone. Please excuse my brevity.