[Hackage] #539: add way to query package dependency graph

[Hackage]

#539: add way to query package dependency graph
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  Reporter:  ganesh              |        Owner:      
      Type:  enhancement         |       Status:  new 
  Priority:  normal              |    Milestone:      
 Component:  cabal-install tool  |      Version:  HEAD
  Severity:  normal              |     Keywords:      
Difficulty:  unknown             |   Ghcversion:      
  Platform:                      |  
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 I'd like to be able to list all the forward or reverse dependencies of a
 package, optionally recursively.

 The attached patch makes a 'cabal depends' command that does this, but
 Duncan (quite reasonably) doesn't want a proliferation of top-level
 commands. Instead it should be integrated into cabal info in some
 appropriate way, but this probably requires some refactoring of that
 command first.

 The attached patch could also be improved in (at least) two ways:
  - Deal with package version numbers as well as names. This involves
 matching the constraints on version numbers against specific version
 numbers.
  - Use a less naive transitive closure calculation.

-- 
Ticket URL: <http://hackage.haskell.org/trac/hackage/ticket/539>
Hackage <http://haskell.org/cabal/>
Hackage: Cabal and related projects