ExtLib is a project aiming at providing a complete - yet small -
standard library for the OCaml programming language. The purpose of
this library is to add new functions to OCaml Standard Library
modules, to modify some functions in order to get better performances
or more safety (tail-recursive) but also to provide new modules which
should be useful for the average OCaml programmer.

ExtLib is not directly related to OCaml authors (INRIA) although this
library can be seen as a proposal for inclusion in the official
distribution.

WWW: https://github.com/ygrek/ocaml-extlib/