cvs commit: fptools/ghc/compiler/types InstEnv.lhs

[Simon Peyton Jones]

simonpj     2004/08/16 02:54:53 PDT

  Modified files:
    ghc/compiler/types   InstEnv.lhs 
  Log:
  	-------------------------------
  	Add instance information to :i
   	Get rid of the DeclPool
  	-------------------------------
  
  1.  Add instance information to :info command.  GHCi now prints out
      which instances a type or class belongs to, when you use :i
  
  2.  Tidy up printing of unqualified names in user output.
      Previously Outputable.PrintUnqualified was
  	type PrintUnqualified = Name -> Bool
      but it's now
  	type PrintUnqualified = ModuleName -> OccName -> Bool
      This turns out to be tidier even for Names, and it's now also usable
      when printing IfaceSyn stuff in GHCi, eliminating a grevious hack.
  
  3.  On the way to doing this, Simon M had the great idea that we could
      get rid of the DeclPool holding pen, which held declarations read from
      interface files but not yet type-checked.   We do this by eagerly
      populating the TypeEnv with thunks what, when poked, do the type
      checking.   This is just a logical continuation of lazy import
      mechanism we've now had for some while.
  
  The InstPool and RulePool still exist, but I plan to get rid of them in
  the same way.  The new scheme does mean that more rules get sucked in than
  before, because previously the TypeEnv was used to mean "this thing was needed"
  and hence to control which rules were sucked in.  But now the TypeEnv is
  populated more eagerly => more rules get sucked in.  However this problem
  will go away when I get rid of the Inst and Rule pools.
  
  I should have kept these changes separate, but I didn't.  Change (1)
  affects mainly
  	TcRnDriver, HscMain, CompMan, InteractiveUI
  whereas change (3) is more wide ranging.
  
  Revision  Changes    Path
  1.33      +14 -8     fptools/ghc/compiler/types/InstEnv.lhs