Issue 521

Haskell Weekly Issue 521 covers several community highlights: a video on selective functors as an alternative to monads and applicative functors, a post on achieving a 5x speedup in the xreferee linter using elemIndex, a comparison of Haskell vs R and Pandas for data exploration, and a guide to writing a WebSocket server for a turn-based game. Brief items include Ghcitty (an enhanced GHCi with syntax highlighting and Hoogle integration), haskell-flake 1.0.0 (now decoupled from flake-parts), and stm-ringbuffer (a fixed-size STM ring buffer outperforming TBQueue). Community show-and-tell features Lawvere theory encodings in Haskell and a Brick TUI dashboard driven by Nix files.