[Haskell-cafe] odd problem with export list of System.IO

[Manlio Perillo]

Johan Tibell ha scritto:
> On Sun, Mar 1, 2009 at 3:07 PM, Manlio Perillo <manlio_perillo at libero.it> wrote:
>> Hi.
>>
>> Maybe I'm missing something, but I don't understand why the following
>> program:
>>
>> module Main where
>> import System.IO (Handle, withFile, ReadMode)
> 
> You want to import IOMode(..), not ReadMode. The latter is a data
> constructor of the IOMode type.
> 

import System.IO (Handle, withFile, IOMode(ReadMode))

solved the problem, thanks.


However, why individual data constructors of the IOMode type are not 
exported?


Thanks  Manlio