Command to install and load packages

[GitHunter0]

Cool package. One very useful addition would be to have a command similar to pacman::p_load() to load packages after installation (if necessary). Do you guys plan to add that?

[gaborcsardi]

Loading the package is a very different operation from installing it, it is better not to mix the two, so we won't add that.

[holgerbrandl]

Clearly, it's different operations, but it's the most typical workflow in the beginning of most R scripts: check if a package is locally installed, install it if not, and load it subsequently. So in this regard p_load serves a very common need. I struggle to envision use cases where one may not want to load a package that was just installed.

[gaborcsardi]

I don't doubt that people want this kind of function, there is plenty of p_load() use on GitHub. Although, if they are happy with p_load(), then I am not sure if we need another implementation of the same thing in pak.

[gaborcsardi]

For the record, p_load() has a lot of issues so if we'll ever have a function that you'd call at the top of scripts to install & load the required packages, it would work somewhat differently.

Most importantly, it would be nice if

pak::script_init_lib(c("user/repo", "pkg1", "pkg2"))

could ensure that the required versions are installed, i.e. user/repo from GitHub, and pkg1 and pkg2 from some CRAN-like repo.

(The script_init_lib() name is temporary.)

Plus possibly, it could

• check if these packages are already loaded, and warn/error if the wrong versions are loaded,
• optionally install the packages into a local library and load them from there,
• optionally print a nice package version table.

Anything else?

[holgerbrandl]

Thank you for looking into the idea.

Regarding the question about the need for another implementation. https://github.com/trinker/pacman has not been touched for 4 years, so the clock is clicking until it fails to work. That's why I got curious about pak in the first place.

Regarding your requirements analysis, I've never looked under the hood of p_load and I can't contribute anything substantial here. I feel that p_load is more important than p_load_gh since most packages are released on cran or similar, but 1 out 10 packages comes directly from github in my experience so p_load_gh
would be also important for consistency.