I hear they are good, make it easier to maintain code-bases. Most often I reach for python to get the job done. Does anyone have experiences with functional languages for larger projects?
In particular I am interested to learn more on how to handle databases, and writing to them and what patterns they come up with. Is a database handle you can write to not … basically mutable state, the arch-nemesis of functional languages?
Are functional languages only useful with an imperative shell?


Functional languages are inherently built on non-functional ones, for the same reason that object oriented languages are built on non object oriented ones, because cpus are fundamentally not object oriented or functional.
They are computational machines with specific instructions around moving values in memory and performing certain operations on them.
Assembly / machine code is always, at a fundamental level, imperative programming, and all higher ordered languages have to translate to these imperative instruction sets / languages.
However, there is an OS that tries to be functional as much as possible though, and that’s a Linux distribution called NixOS, based on the functional language Nix.