[Rd] R History: Why is there no importFrom() function?

[Michael Lawrence]

I can't speak to the history per se, but I can give an opinion on the
current situation. R is a programming language, as is Python, but R is
also a system for interactive data analysis. Outside of the
software/package context, library() is almost always sufficient. When
it is not, consider "foo <- package::foo". While not as well
structured as an importFrom() call, it does make the side effect
explicit. When that becomes onerous, it is probably past time to
transition to a package.

Michael

On Sat, Jul 21, 2018 at 7:54 PM, Aaron Jacobs <atheriel using gmail.com> wrote:
> Excuse me if this is inappropriate content for this list, but I thought it
> might be the best place -- and the best audience -- to ask about a design
> decision for the R language.
>
> Programs or analyses written in R typically use library() to pull in
> functions from non-core packages. This differs markedly from most
> languages*, which usually offer some way to selectively import symbols. For
> example, in Python you'd see "from random import randint", and so on.
>
> Within R packages, the NAMESPACE file provides this exact functionality
> with the importFrom() directive, but the R language itself does not expose
> this as a function for regular users.
>
> I know that R did not have namespaces for some of its early existence, but
> I'm curious as to why the language never acquired an import() or
> importFrom() replacement for library() when it did get them. Was it purely
> for compatibility with S and earlier R versions? Or was there a principled
> difference of opinion on how R code should be written at stake?
>
> Any insight from those of you familiar with R's history would be deeply
> appreciated.
>
> Regards,
> Aaron
>
> ps. I am aware of the very clever "import" package, which provides exactly
> this feature -- I am more wondering why such an approach was never adopted
> by the language itself.
>
> * Most languages with real modules/namespaces, I mean.
>
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