[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.