Re: [Haskell-cafe] There is no null; Maybe/Option types

[Henning Thielemann]

On Fri, 22 Apr 2011, Maciej Marcin Piechotka wrote:
On Fri, 2011-04-22 at 21:26 +0200, Henning Thielemann wrote:

In idiomatic Haskell you would write

case userList of
    Nothing -> Nothing
    Just plainUserList =
       let user = findUser "bob" plainUserList
       ...

since (userList /= Nothing) requires an Eq instance without need and it
requires fromJust. Or was there an educational purpose to write it with
(/= Nothing) ?

Using 'more advanced haskell'

email = getEmail =<< findUser "bob" =<< userList

This is what Christopher Done wrote some lines below the code, that I 
quoted.

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