You have a point, declarative approaches almost never delivers as promised, which is "you don't have to worry about implementation". In reality, as you say, yo

You have a point, declarative approaches almost never delivers as promised, which is "you don't have to worry about implementation". In reality, as you say, you end up with edge cases where you still need to dive into the implementation in order to find out what's happening. I don't think it's a good enough argument to dismiss the whole paradigm though. Im prefectly happy with my declarative regular expressions that work 90% of the time, and rather take the hit debugging those hairy 10% that end up not working well, than writing my own imperative parser every time and repeatedly deal with those off by one errors etc.. When you say "it never works" I suspect you really mean "it never works in 100% on the cases".