John Meacham wrote:
Actually what I really need to do to make issues like that maybe thing
from coming up is allow derived instances to happen at a place other
than where the type is delared. pulling in 'Read' to declare Bool just
doesn't work that well. and I don't like all these manually written
instances cluttering up the libraries..
perhaps a pragma.. like {-# DERIVE: Enum Bool #-}. or putting "deriving
'Read'" will just add a placeholder that will be expanded to a real
derivation when the read class comes into scope. though, that is sort of
hacky as I would have to fudge namespace resolution in deriving clauses.
now that GHC has "standalone deriving" syntax, standalone deriving might
be something to start from
do other compilers do something clever here? it looks like ghc does what
I do but with CPP tricks and basically writes out its own instances in
full.
John
_______________________________________________
jhc mailing list
[email protected]
http://www.haskell.org/mailman/listinfo/jhc
