Comment by lukaslalinsky

Whenever I hear someone talking about purely functional programming, no side effects, I wonder what kind of programs they are writing. Pretty much anything I've written over the last 30 years, the main purpose was to do I/O, it doesn't matter whether it's disk, network, or display. And that's where the most complications come from, these devices you are communicating with have quirks that need you need to deal with. Purely functional programming is very nice in theory, but how far can you actually get away with it?