Install libghc-regex-base-doc by entering the following commands in the terminal:
sudo apt update sudo apt install libghc-regex-base-doc
Description:
GHC library providing an API for regular expressions; documentation
A library containing the interface API for the Haskell regular expressions library packages regex-posix, regex-pcre, regex-parsec, regex-tdfs, regex-dfa. . This package provides the documentation for a library for the Haskell programming language. See http://www.haskell.org/ for more information on Haskell.
Homepage: http://sourceforge.net/projects/lazy-regex
Version: 0.93.2-10build1
Section: universe/doc