Install alex by entering the following commands in the terminal:
sudo apt update sudo apt install alex
Description:
lexical analyser generator for Haskell
Alex is a tool for generating lexical analysers in Haskell, given a description of the tokens to be recognised in the form of regular expressions. It is similar to the tool lex or flex for C/C++.
Homepage: http://www.haskell.org/alex/
Version: 3.2.3-1
Section: universe/devel