ANN: H98 FFI Addendum 1.0, Release Candidate 10

[John Meacham]

This was discussed here before and there seemed to be some support for
it, but how about adding the empty data declaration extension to the FFI
spec? They are used quite often to represent the abstract targets of
pointers as in:

data Foo
data Bar

foreign  lookupBar :: Ptr Foo -> IO (Ptr Bar)  -- psuedocode

the FFI is the perfect place to use the extension and it is trivial to
implement. The problem is made even worse by the fact that you can't use
the beginning underscore trick with data constructors since an
underscore counts as a lowercase letter so there is no way to avoid
unused constructor warning messages without resorting to using
extensions or resorting to compiler-specific pragmas which are
unelegant.

so I guess my argument is in a nutshell, everyone implements them. they
are a very good fit with the FFI and they make code more readable and
supress spurious warnings.
        John


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John Meacham - California Institute of Technology, Alum. - john at foo.net
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