A lot of the code is taken from glguy's version of the same thing. This was mostly an opportunity to practice parsing and meta programming in Haskell
[fmt|%d&(,)|]This will parse 1,2,3,4,5 fine.
To allow leading and trailing space we can do the following
[fmt|%d&(( )*,( )*)|]Now we can parse 1,2, 3,2 , 4 just fine.
Can do much much more things too. Can't be arsed writing it all out atm.
E.g. to parse day 20 of advent of code
parser :: String -> [(String, [String])]
parser = [fmt|(((%y?%s)! -> %s&(, ))%n)*|]