A transient data structure is a combination of an ephemeral data structure, a persistent data structure, and fast conversions between them. We present a transient sequence data structure that supports efficient read and write access at an arbitrary index with worst-case time complexity O ( K log K n ), pushing and popping at either end with complexity O ( K log K n ), and splitting and concatenation with complexity O ( K log K n +log K 2 n ), where K is a user-defined chunk size and n is the length of the sequence. We provide a detailed analysis of this data structure and show that, in many favorable scenarios, it performs much better than these pessimistic bounds might suggest. Furthermore, we describe its implementation, and provide a synthetic benchmark to evaluate the performance of push and pop . We believe that it is a good candidate for a one-size-fits-all, general-purpose sequence data structure.

@article{paperbot3643,
  title = {A Catenable, Splittable, Transient Sequence Data Structure},
  author = {Arthur Charguéraud and François Pottier},
  journal = {Proceedings of the ACM on Programming Languages},
  volume = {10},
  number = {ICFP},
  year = {2026},
  doi = {10.1145/3828706}
}