replace package finding logic with packrat

[AdamSpannbauer]

yeah. it does it better

[AdamSpannbauer]

I added a first pass and it fails devtools::check from a CRAN perspective. Using non-exported functions is kind of a no-go from a safe code perspective (i.e. packrat could change what the non-exported function is doing without warning since they don't intend for others to use it).

We'd have to gut the logic and make it our own.

[AdamSpannbauer]

from R packages by Hadley

Similarly you are not allowed to use ::: to access non-exported functions from other packages. Either ask the package maintainer to export the function you need, or write your own version of it using exported functions. Alternatively, if the licenses are compatible you can copy and paste the exported function into your own package. If you do this, remember to update Authors@R.

I think if we go with packrat's process, then it's worth posting an issue in packrat requesting the functionality we're after to be exported. The entirety of the logic they use would be a lot to copy/paste/maintain. It supports pulling dependencies from .R, .Rmd, .Rnw, & .Rpres. I pulled all the logic just for .R, and it would be maintainable IMO, but the logic for the inlcusion of all the formats gets fairly large/complex.

The current logic 'supports' all these file types given that it uses dumb string matching logic rather than parsing expressions. The dumbness grants flexibility at the cost of 'safety' (i.e. listing a string with ':::' being a dependency).

[AdamSpannbauer]

I'd say we put this issue on hold to see what packrat devs respond to my issue with. If they refuse we should discuss how to best proceed.

[AdamSpannbauer]

Got a response on the issue in packrat. Working is being done on renv to replace packrat. renv will have renv::dependencies() that could serve us well. Not sure release date for renv, but it is currently not on CRAN