Install libghc-regex-posix-doc by entering the following commands in the terminal:
sudo apt update sudo apt install libghc-regex-posix-doc
Description:
API documentation for regex-posix Haskell library
A library containing a POSIX regular expression backend conforming to the interface API of regex-base. . This package contains the API documentation of the library.
Homepage: http://sourceforge.net/projects/lazy-regex
Version: 0.95.2-9build1
Section: universe/doc