[GHC] #10478: Shorter import syntax

[GHC]

#10478: Shorter import syntax
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        Reporter:  acowley           |                   Owner:
            Type:  feature request   |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.10.1
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:  Phab:D1238
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Comment (by simonpj):

 Thanks.  I have started a wiki page for you, [wiki:ShorterImportSyntax].

 Omitting package imports and source imports, the
 [https://www.haskell.org/onlinereport/haskell2010/haskellch5.html#x11-1010005.3
 import declaration grammar] is
 {{{
 impdecl →       import [qualified] modid [as modid] [impspec]
 }}}
 What I can't figure out from the above is whether you propose any
 ''change'' in grammar.  Are you saying that switching the order of `as
 modid` and `impspec` makes the difference?  If so could you perhaps just
 give the new grammar on the wiki page?

 > In such a case, all identifiers exported by modid are accessible behind
 the prefix given by the as

 How does that differ from this:
 {{{
 import M as N
 }}}

 I'm not being picky; I'm just genuinely trying to understand what you
 propose but (like all future GHC users) without reading the long
 discussion that led up to it.

 Rather than replying to me inline here, it'd be great to update the wiki
 page to be as precise as you possibly can, add some examples, add links to
 the discussion and analysis you have done.  That way the wiki becomes a
 standalone description of the proposed feature.  Thanks!

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10478#comment:22>
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