On 2014-01-09 at 08:46:28 +0100, Ramin Honary wrote: [...]
So as we all know, when there is no exports list in a module declaration, everything in the top level is exported by default.
If you provide an exports list, everything is hidden except what you declare in the exports list.
Btw, that's almost symmetric with an import statement lacking an 'impspec' and one providing a non-"hiding" 'impspec'; Otoh I've been wondering for some time why the export declaration doesn't support the "hiding" modifier, e.g. module M hiding (A, B(..), C(..), abc) where ... to make the export declaration a bit more symmetric with 'impsec' on the import side.
I think a good way to hide things without an exports list might be to simply prefix the type signature with a tilde character. For example:
module M where
~type A = () ~newtype B = B () ~data C = MkB1 () | MkB2 ()
~abc :: () abc = ()
increment :: Int -> Int increment = (+1)
So in this example, the module M would only export the "increment" function, everything else would be hidden.
So in order to hide a function/value this way, you have to write a type-signature for 'abc', in order to be able to declare 'abc' non-exported? [...] Cheers, hvr