ignore library path for renv and packrat

[colearendt]

When using tools like renv or packrat, styler seems to be going through the entire library by default (and styling all of the R packages in use).

By default, styler should probably either:

• ignore .libPaths() folders
• be savvy about recognizing a library of R packages (and ignore)

[lorenzwalthert]

thanks. Are you talking about the style_dir() API or which function?
Related as far as file filtering goes: #515
I don't think we can easily or should use .libPaths(). But we could potentially ignore renv and packrat directories.

[colearendt]

Yes, I believe it was style_dir() that gave me this behavior. Ignoring renv / packrat would work just fine - I was hoping there was a more generic implementation (lest some other package have the same behavior). However, renv / packrat is simple enough and solves the need 😄

[lorenzwalthert]

I think we better add an argument exclude_dirs to style_dir() and make the default such that packrat and renv are ignored, so it's transparent to the end user what happens.