[anon_d]

Functional programming doesn't actually compete with imperative programming.

In practice, functional programming is a way of organizing imperative programs. Kind of like how OO is a way of organizing imperative programs.

Almost all applications written in Haskell use the IO monad quite a bit, for example. Large Haskell projects generally use a lot of C libraries, and sometimes even directly include C code for performance sensitive bits.

[gnulinux]

I think part of the problem is no implementation has an exciting story about writing the "shell" part in a different language. I love love love writing purely functional code. Probably my favorite thing to do. But what a lot people who also like functional programming are missing is writing imperative code in functional languages almost invariably sucks. At the end of the day we all have to write the "shell" part of our Haskell programs, and my programs always end up in a horrific mess of IO, State and other monads.

[anon_d]

> writing imperative code in functional languages almost invariably sucks.

I don't agree at all!

Haskell is extremely pleasant for imperative programming. There's a learning curve for sure, but you get a lot in return. (STM is one small example). I would much rather write imperative Haskell than Python.

It does gets messy when you start writing really low level code (direct pointer manipulation, etc). And it sucks for small scripts (too much project boilerplate, small standard library). But those are the only real pain-points.

[ParetoOptimal]

> At the end of the day we all have to write the "shell" part of our Haskell programs, and my programs always end up in a horrific mess of IO, State and other monads.

You can very successfully keep nearly all IO at the edges and do the heavy lifting in pure functions if you make it a goal.