In class, we used denotational semantics to evaluate a decimal number using a function Mdec. We could define a similar function to evaluate hexadecimal numbers as follows: 2. MhexDigit ( 'F' ) = MhexDigit ( 'f' ) = 15 Myex("d") = MhexDigit('d') (Base case - one-digit string) Note that I am allowing both upper- and lower-case letters for the hexadecimal digits for 10,11,..,15. Implement a Haskell function mHexDigit to return the numerical value of a single hexadecimal digit. You will need to use guards and the ord function from the Haskell module Data.Char. The Haskell type should be mHexDigit::Char -> Int Now, implement a Haskell function mHex::String -> Int to evaluate a hexadecimal number given as a string Finally, since mHexDigit is only used by mHex, implement a Haskell function mHex'::String -> Int in which mHexDigit is defined using the where or let contruct. In class, we used denotational semantics to evaluate a decimal number using a function Mdec. We could define a similar function to evaluate hexadecimal numbers as follows: 2. MhexDigit ( 'F' ) = MhexDigit ( 'f' ) = 15 Myex("d") = MhexDigit('d') (Base case - one-digit string) Note that I am allowing both upper- and lower-case letters for the hexadecimal digits for 10,11,..,15. Implement a Haskell function mHexDigit to return the numerical value of a single hexadecimal digit. You will need to use guards and the ord function from the Haskell module Data.Char. The Haskell type should be mHexDigit::Char -> Int Now, implement a Haskell function mHex::String -> Int to evaluate a hexadecimal number given as a string Finally, since mHexDigit is only used by mHex, implement a Haskell function mHex'::String -> Int in which mHexDigit is defined using the where or let contruct