Authors = [(String, Int)]
File Filename DateTime Authors
例:
File "DSC023.jpg" "01/05/2012 22:40" [("Test1",1),("Test2",2)]
如何搜索 DSC023.jpg 并将其他作者添加到列表中?
findFile n = find ((File x _ _ _) -> x == n) fileDatabase
你需要几个函数:
addAuthor author File x y as = File x y (author:as)
fileName File n _ _ _ = n
findFile name = find (x -> (fileName x) == name)
这应该为您提供构建所需功能所需的一切。