# Announcing Sek, an efficient implementation of sequences **URL:** \ **Category:** Ecosystem\ **Created:** [April 4, 2020, 10:14am UTC](https://discuss.ocaml.org/t/announcing-sek-an-efficient-implementation-of-sequences/5442 "2020-04-04T10:14:09Z")\ **Posts on this page:** 1\ **Showing post:** 1
**Author:** ![fpottier](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ocaml.org/fpottier/32/677_2.png) [@fpottier](https://discuss.ocaml.org/u/fpottier)\ **Post date:** [April 4, 2020, 10:14am UTC](https://discuss.ocaml.org/t/announcing-sek-an-efficient-implementation-of-sequences/5442/1 "2020-04-04T10:14:09Z")
Fellow OCaml users, We are pleased to announce the first release of Sek, an OCaml library that offers an efficient implementation of sequences. The library offers both ephemeral (mutable) sequences and persistent (immutable) sequences, and offers constant-time conversions between these flavors. It supports all of the standard operations on stacks, queues, deques (e.g. push, pop at either end), catenable sequences (concat, split), and random access sequences (get, set). Data is stored internally in chunks (fixed-capacity arrays), which is why this data structure is known as a chunK SEquence. It is intended to achieve excellent time complexity and memory usage. This is an initial release. The library has not been tested in production, but has received extensive unit testing, via afl-fuzz and ocaml+afl – which are remarkably effective tools, by the way! This is work in progress; more features, such as iterators, will be added in the future. To install Sek, just type ```auto opam update && opam install sek ``` Documentation is [online](http://cambium.inria.fr/~fpottier/sek/doc/sek/Sek/index.html). Feedback is welcome! Arthur Charguéraud François Pottier with contributions by Émilie Guermeur --- _[View the full topic](https://discuss.ocaml.org/t/announcing-sek-an-efficient-implementation-of-sequences/5442)._