[GHC] #1799: Retain export-list order in ModIface, use it in :browse

[GHC]

#1799: Retain export-list order in ModIface, use it in :browse
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 Reporter:  guest    |          Owner:             
     Type:  bug      |         Status:  new        
 Priority:  low      |      Milestone:  6.10 branch
Component:  GHCi     |        Version:  6.6.1      
 Severity:  normal   |     Resolution:             
 Keywords:           |     Difficulty:  Unknown    
 Testcase:           |   Architecture:  Unknown    
       Os:  Unknown  |  
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Comment (by simonpj):

 Replying to [comment:3 simonmar]:

 > Ideally I'd like to retain the order of the export list in the
 `ModIface`, so that all `:browse M` output (as opposed to `:browse *M`)
 would appear in export-list order.  The compiled/interpreted distinction
 would then disappear.  At the moment it appears that `md_exports` in
 `ModDetails` is always sorted by `OccName`.

 There seem to be two places where the order might get scrambled:

  * The call to `nubAvails` in `RnNames.rnExports`.  This combines `T(C)`
 with `T(D)` to give `T(C,D)`.   I'm not sure whether you want to retain
 exactly the former.

  * The `groupFM` stuff in `MkIface.mkIfaceExports`, which further groups
 exports by modules.  This part could readily be omitted (although the
 interface file format would then change).

 The other potential cost is that `module M( a,b )` would be recorded as a
 change from `module M( b, a )` and hence force recompilation.  That
 probably barely matters, though.

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1799#comment:4>
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