If there is to be such a language feature, I strongly feel it should be via
something like
module Long.Name.M( f, g, h ) as K where ...
I do not want to try to piggy-back on the possible meaning of a self-import;
it’s just asking for trouble, as Iavor points out.
Using “as M” in the module header would be simple. It is easy to explain and
fairly easy to implement. I don’t think there are any knock-on complications.
So if enough people want it, and someone is prepared to implement it (with a
language extension flag of course), then I’d be OK with that. I’m unsure that
it’s worth the effort, but I’m happy to let users decide.
Simon
From: Glasgow-haskell-users [mailto:glasgow-haskell-users-boun...@haskell.org]
On Behalf Of Iavor Diatchki
Sent: 30 September 2014 13:18
To: j...@repetae.net
Cc: GHC Users Mailing List; ghc-devs; Herbert Valerio Riedel
Subject: Re: Aliasing current module qualifier
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<mailto: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<mailto:allber...@gmail.com>> wrote:
On Mon, Sep 29, 2014 at 4:19 AM, Herbert Valerio Riedel
<h...@gnu.org<mailto: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<mailto:allber...@gmail.com>
ballb...@sinenomine.net<mailto:ballb...@sinenomine.net>
unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net
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