add string implementation, can handle partial string slices
finish core implementation, added Index object
fix up the logic
add in new SliceOption object, cleaning up tests
python part of random ops
added random select sub policy
validators added
comments added, remaining issues addressed
add more python test cases
fix ci
fix CI
fix order of include files
addr review cmts
addr review cmts
reorg file
fix compile err
address review cmts
address review cmts