Problem 315. Valid Chess Moves

Using standard Algebraic notation ('' for a pawn), given previous move and a next move, output true if it is a valid move or false otherwise. Assume there are no other pieces on the chess board, that the piece can be either black or white (whichever generates a valid result) and the previous move was valid. Examples:

Moving a pawn one space:
('c5','c6') -> true 

Moving a bishop non-diagonally:
('Bb7','Bd7') -> false