Make Cacher object
make_cacher(f_path = function() getOption("rmonad.cache_dir"),
f_save = saveRDS, f_get = readRDS, f_del = unlink,
f_ext = function(cls) ".Rdata")A function for finding the directory in which to cache results
function of x and filename that saves x to the path filename
function of filename that retrieves the cached data
function of filename that deletes the cached data
function of class(x) that determines the filename extension
A function that builds a local cache function for a value
Other cache: clear_cache,
fail_cache, make_recacher,
memory_cache, no_cache,
void_cache