Hi Joachim,
I used the following in the past:
module M (PublicClass(..)) where
class HiddenClass a
class HiddenClass a => PublicClass a where
...
instance HiddenClass SomeType
instance PublicClass SomeType where
...
Now users of M can't declare instances of PublicClass because they don't
have its superclass HiddenClass in scope.
Regards,
Bas
On Aug 17, 2013 8:10 PM, "Joachim Breitner"
Hi,
for some reason I was under the impression that if I don’t export the methods of a class, then no user of my module can create instances. But I was wrong and in fact they can; the methods will just all be bound to "error ...".
Is there really no way to create a class so that no-one else can create any instances?
Greetings, Joachim
-- Joachim “nomeata” Breitner mail@joachim-breitner.de • http://www.joachim-breitner.de/ Jabber: nomeata@joachim-breitner.de • GPG-Key: 0x4743206C Debian Developer: nomeata@debian.org
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