libre-ocaml-dev 1.6.1-2build1 (amd64 binary) in ubuntu bionic

 RE is regular expression library for OCaml. The following styles of
 regular expressions are supported:
  * Perl-style regular expressions (module Re_perl);
  * Posix extended regular expressions (module Re_posix);
  * Emacs-style regular expressions (module Re_emacs);
  * Shell-style file globbing (module Re_glob).
 .
 It is also possible to build regular expressions by combining simpler
 regular expressions (module Re)
 .
 This package contains the development modules you need to use RE in
 your programs.