21 Sep
2006
21 Sep
'06
3:13 a.m.
On 9/20/06, Misha Aizatulin <avatar@hot.ee> wrote:
What I need it for is serialization of datatypes with existential constructors (see http://haskell.org/pipermail/haskell-cafe/2006-September/018041.html) I am having a box like
data Box = forall a. Cxt a => Box a and want to write a Read instances for it.
Can you define instance Cxt a => Read (Box a)? If not, then you need typecase and Haskell does not really support that. -- Taral <taralx@gmail.com> "You can't prove anything." -- Gödel's Incompetence Theorem