The variables package offers a small collection of objects describing conceptual variables and corresponding methods, for example for generating a grid of values for a (yet) unmeasured variable.
The package was written to support the basefun and mlt packages and will be of limited use outside these packages.
This package is authored by Torsten Hothorn <Torsten.Hothorn@R-project.org>.
Torsten Hothorn (2018), Most Likely Transformations: The mlt Package, Journal of Statistical Software, forthcoming. URL: https://cran.r-project.org/package=mlt.docreg