his function exposes internal stan functions in R from a user
supplied list of target files. Allows for testing of stan functions in R and
potentially user use in R code.
expose_stan_fns(files, target_dir, ...)
No return value, called for side effects
A character vector indicating the target files.
A character string indicating the target directory for the file.
Additional arguments passed to rstan::expose_stan_functions()
.