yi binary package in Ubuntu Focal amd64

 Yi is a text editor written in Haskell and extensible in Haskell. The goal
 of the Yi project is to provide a flexible, powerful, and correct editor
 for haskell hacking.
 .
 This package comes pre-configured with the default configuration. If
 you want to build your custom-configured version, make sure that
 libghc-yi-core-dev is installed and put your configuration in
 ~/.config/yi/yi.hs

Source package