Hello, What semantics are you using for recursive modules? As far as I see, if you take a least fixed point semantics (e.g. as described in "A Formal Specification for the Haskell 98 Module System", http://yav.github.io/publications/modules98.pdf ) this program is incorrect as the module does not export anything.
While this may seem a bit counter intuitive at first, this semantics has the benefit of being precise, easily specified, and uniform (e.g it does not require any special treatment of the " current " module). As an example, consider the following variation of your program, where I just moved the definition in a sperate (still recursive) module: module A (M.x) where import B as M module B (M.x) where import A as M x = True I think that it'd be quite confusing if a single recursive module worked differently then a larger recursive group, but it is not at all obvious why B should export 'x'. And for those who like this kind of puzzle: what should happen if 'A' also had a definition for 'x'? Iavor On Sep 29, 2014 11:02 PM, "John Meacham" <j...@repetae.net> wrote: > You don't need a new language construct, what i do is: > > module AnnoyinglyLongModuleName (M.length, M.null) where > > import AnnoyinglongLongModuleName as M > > I think ghc would need to be extended a little to make this convienient as > it doesn't handle recursive module imports as transparently. > > John > > On Mon, Sep 29, 2014 at 8:47 AM, Brandon Allbery <allber...@gmail.com> > wrote: > >> On Mon, Sep 29, 2014 at 4:19 AM, Herbert Valerio Riedel <h...@gnu.org> >> wrote: >> >>> Now it'd be great if I could do the following instead: >>> >>> module AnnoyinglyLongModuleName (M.length, M.null) where >>> >>> import AnnoyinglyLongModuleName as M -- <- does not work >>> >> >> I think if I wanted this syntax, I'd go for: >> >> module AnnoyinglyLongModuleName as M where ... >> >> -- >> brandon s allbery kf8nh sine nomine >> associates >> allber...@gmail.com >> ballb...@sinenomine.net >> unix, openafs, kerberos, infrastructure, xmonad >> http://sinenomine.net >> >> _______________________________________________ >> Glasgow-haskell-users mailing list >> Glasgow-haskell-users@haskell.org >> http://www.haskell.org/mailman/listinfo/glasgow-haskell-users >> >> > > > -- > John Meacham - http://notanumber.net/ > > _______________________________________________ > ghc-devs mailing list > ghc-d...@haskell.org > http://www.haskell.org/mailman/listinfo/ghc-devs > >
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