`bb_put/2` (non-backtrackable) and `bb_b_put/2`
(backtrackable).
- [x] Delimited continuations based on reset/3, shift/1 (documented in
- "[Delimited Continuations for Prolog](https://www.swi-prolog.org/download/publications/iclp2013.pdf)").
+ "[Delimited Continuations for Prolog](https://biblio.ugent.be/publication/5646080/file/5646081)").
- [x] Tabling library based on delimited continuations
- (documented in "[Tabling as a Library with Delimited Control](https://www.ijcai.org/Proceedings/16/Papers/619.pdf)").
+ (documented in "[Tabling as a Library with Delimited Control](https://biblio.ugent.be/publication/6880648/file/6885145.pdf)").
- [x] A _redone_ representation of strings as difference lists of
characters, using a packed internal representation.
- [x] clp(B) and clp(ℤ) as builtin libraries.
- [ ] Greatly reducing the number of instructions used to compile disjunctives.
- [ ] Storing short atoms to heap cells without writing them to the atom table.
- [ ] A compacting garbage collector satisfying the five properties of
- "[Precise Garbage Collection in Prolog](https://www.swi-prolog.org/download/publications/lifegc.pdf)." (_in progress_)
+ "[Precise Garbage Collection in Prolog](https://www.complang.tuwien.ac.at/ulrich/papers/PDF/2008-ciclops.pdf)." (_in progress_)
- [ ] Mode declarations.
## Phase 3