Parsing combinators

Some derived combinators

• cmd  :: String -> a -> P a
  flag :: String -> P Bool
  run  :: P (IO a) -> IO a
  
  kw   :: String -> P ()
  many :: P a -> P [a]
  some :: P a -> P [a]
  opt  :: P a -> P (Maybe a)
  (#@) :: (a->b) -> P a -> P b
  

• We saw the first three in the example