Define a Haskell function which analyzes regular expressions defined using this type.

data RE a -- RE's over an alphabet defined by 'a' = Empty -- empty regular expression | Sym a -- match the given symbol | RE a :+: RE a -- concatenation of two regular expressions | RE a :|: RE a -- choice between two regular expressions | Rep (RE a) -- zero or more repetitions of a regular expression | Rep1 (RE a) -- one or more repetitions of a regular expression deriving (Show)

matchEmpty :: RE a -> Bool This function returns true if the regular expression matches an empty string. Note that the type does not include any constraints on the alphabet. Among other things, this means that it requires 'a' to be an instance of Eq. Some examples: matchEmpty (Sym 'a') = False matchEmpty (Rep (Sym 'a' :+: Sym 'b')) = True matchEmpty (Rep1 (Sym 'a' :|: Empty)) = True