simListsimList.
makeDigestible(simList)
"makeDigestible"(simList)simListsimList object, but with no
reference to any environments
simList, except that all references
to local environments are removed.
Specifically, all functions (which are contained within environments) are
converted to a text representation via a call to format(fn).
Also the objects that were contained within the .envir slot are hashed
using digest::digest.
The paths slot is not used (to allow comparison across platforms); it's
not relevant where the objects are gotten from, so long as they are the same.
The .envir slot is emptied (NULL).
The object is then converted to a simList_ which has a .list slot.
The hashes of the objects are then placed in that .list slot.
cache.