Hello everyone ,
I wanted to do a small program which read a txt with fruit's name in each line and then print how many fruits I have of each type. something like these:
apple
apple

and then

[(apple,2)]

I came up whit this

import qualified Data.Map as Map
import Data.List
import System.IO

main =
    do
      file <- readFile "fruits.txt"
      let answer = proccessFile $ lines file


      putStrLn (show answer)

proccessFile :: [String] -> [(String,Int)]
proccessFile file = Map.toAscList $ parseFile Map.empty  file
    where parseFile fruits [] = fruits
          parseFile fruits_map (x:xs) = parseFile (Map.insertWith (+) x 1 fruits_map) xs

It works, but I would like to know how would you do it ?, Share different points of view, different code. Was it a good idea to use a Map ?, Did I separate the code in a proper way, I mean pure - impure ? How can we improve the performance ?

Best Regards for everyone.

Adolfo