The following is an input test. You can add more examples to it:

l = ["matei@gmail.com", "mihai@gmail.com", "tEst@mail.com", "email@email.com", "short@ax.ro"]

Use map, foldr/foldl, instead of recursive functions. Wherever possible, use functional composition and closures.

5.1. Replace uppercases with lowercases from emails. (Do not use recursion). To be able to use character functions from the library, add import Data.Char at the beginning of the program. Use the Internet to find the appropriate character function.

rem_upper l = 

5.2. Write a function which removes emails longer than a given size. Use anonymous functions in your implementation, then think about how you can replace them by a functional composition of more basic functions. Hint: Write your code in steps. Start with the basic idea, then think about how you can write it better and cleaner.

longer :: Int -> [String] -> [String]
longer x = 

5.3. Count the number of emails longer than 12 characters. Use a fold, anonymous functions and functional composition.

howmany l =

5.4. Split the list between first names and email domains. What ingredients (auxiliary functions) are necessary? Use either a fold or a tail-recursive function in your implementation. Example: names_emails [“matei@email.com”] = "matei", "email.com".

names_emails :: [String] -> [[String]]
names_emails l =

5.5. Identify the list of the employed domain names (e.g. gmail.com). Remove duplicates. Use no recursion and no additional prelude function apart from head and tail. Hint think about the sequence of basic operations you want to perform and assemble them using functional composition.

domains :: [String] -> [String]
domains =

(!) 5.6. In some previous exercise you have, most likely, implemented a split function using foldr. Implement one with foldl. Hint: use an example together with the foldl implementation to figure out what the accumulator should do.

splitl :: String -> [String]
splitl = 

5.7. Write a function which extracts the domains from emails, without the dot part. (e.g. gmail). Generalise the previous function splitl to splitBy:: Char → String → [String], and use it each time necessary, in your implementation. Hint: Wherever you want to mix pattern matching with guards, start with the patterns first.

domain :: [String] -> [String]
domain =