A collection of high-level, machine- and OS-independent tools
    for making reproducible and reusable content in R.
    The two workhorse functions are Cache() and prepInputs(). Cache()
    allows for nested caching, is robust to environments and objects with
    environments (like functions), and has deals with some classes of 
    file-backed R objects e.g., from terra and raster packages. 
    Both functions have been developed to 
    be foundational components of data retrieval
    and processing in continuous workflow situations. In both functions,
    efforts are made to make the first and subsequent calls of functions have 
    the same result, but faster at subsequent times by way of checksums
    and digesting. Several features are still under development, including
    cloud storage of cached objects, allowing for sharing between users. Several
    advanced options are available, see ?reproducibleOptions().

Transform coordinates from a specified source to a specified 
 target map projection. This uses the 'PROJ' library directly, by wrapping the 
 'PROJ' package which leverages 'libproj', otherwise the 'proj4' package. The 'reproj()' 
 function is generic, methods may be added to remove the need for an explicit 
 source definition. If 'proj4' is in use 'reproj()' handles the requirement for 
 conversion of angular units where necessary. This is for use primarily to 
 transform generic data formats and direct leverage of the underlying
 'PROJ' library. (There are transformations that aren't possible with 'PROJ' and
 that are provided by the 'GDAL' library, a limitation which users of this 
 package should be aware of.) The 'PROJ' library is available at 
 <https://proj.org/>.

Root Expected Proportion Squared Difference (REPSD) is a nonparametric
  differential item functioning (DIF) method that (a) allows practitioners 
  to explore for DIF related to small, fine-grained focal groups of examinees, 
  and (b) compares the focal group directly to the composite group that will be 
  used to develop the reported test score scale. Using your provided response 
  matrix with a column that identifies focal group membership, this package
  provides the REPSD values, a simulated null distribution of possible REPSD
  values, and the simulated p-values identifying items possibly displaying DIF 
  without requiring enormous sample sizes.