(can_* == can_read, can_write, and can_create) See top of contrib/adc/adc.common-functions for more on this. Note: the old style (calling get_rights_and_owner with $repo, then checking $perm_read, $perm_write, etc.), will still work fine.
Note: "able" still needs bash but it's an easy fix if you need to use it on a bash-challenged machine and care enough