TODO

- Backward not implemented (line 328 in lib/netkat/nka.ml)
- Forall/Exists are not implemented (TODO line 244 in lib/netkat/nkexp.ml)
- command-level expr not implemented (TODO line 29 in lib/netkat/nkpl_parser.ml)
- rangesum not implemented (TODO line 93 in lib/netkat/nkpl_parser.ml)
- The following do not parse:
examples/examples/nkpl/2x2-fabric-slice.nkpl
examples/examples/nkpl/altmethod.nkpl
examples/examples/nkpl/popl14.nkpl
examples/examples/nkpl/scratchpad.nkpl

examples/examples/nkpl/demo.nkpl
examples/examples/nkpl/e1.nkpl
examples/examples/nkpl/e11.nkpl
examples/examples/nkpl/e12.nkpl
examples/examples/nkpl/e13.nkpl
examples/examples/nkpl/e22.nkpl
examples/examples/nkpl/just_set.nkpl
examples/examples/nkpl/lambad.nkpl
examples/examples/nkpl/lamgood.nkpl
examples/examples/nkpl/paper-e1-noslice.nkpl
examples/examples/nkpl/paper-e1.nkpl
examples/examples/nkpl/paper-e2-noslice.nkpl
examples/examples/nkpl/paper-e2.nkpl
examples/examples/nkpl/paper-pre3.nkpl
examples/examples/nkpl/paper-pre4.nkpl
examples/examples/nkpl/paper-pre5.nkpl
examples/examples/nkpl/slice.nkpl
examples/examples/nkpl/test_and_set.nkpl
examples/examples/nkpl/test1.nkpl
examples/examples/nkpl/upf.nkpl

(lambdas, subscripts, slice)