3.8.7.1
  Eliminate warning about nonexhaustive pattern match (thanks Edward Yang)

3.8.7.0
  Works with GHC 7 (thanks Edward Yang)
  cabal sdist now sort of works (and is added to validate)

3.8.6.0
  Matches the camera-ready Haskell'10 paper

3.8.1.0

  Major reorganization per simonpj visit to Tufts 20 April 2010
  Collections

3.7.13.1

  Added function to fold over nodes in graph.

3.7.13.0

  Pointed type replaces WithTop and WithBot, which are now synonyms.
  

3.7.12.3

  Updates to Hoopl in the last week
  =================================


  Interface changes
  -----------------
  The type of AGraph is now abstract.
  It is now recommended to create AGraphs with just three functions:

    <*>          concatenation
    |*><*|       splicing at a closed point
    addBlocks    add C/C blocks out of line

  There are new utility functions in modules Util and XUtil, all
  exported by Compiler.Hoopl.  Here's a selection:

    -- | A utility function so that a transfer function for a first
    -- node can be given just a fact; we handle the lookup.  This
    -- function is planned to be made obsolete by changes in the dataflow
    -- interface.
    firstXfer :: Edges n => (n C O -> f -> f) -> (n C O -> FactBase f -> f)
    firstXfer xfer n fb = xfer n $ fromJust $ lookupFact fb $ entryLabel n
    
    -- | This utility function handles a common case in which a transfer function
    -- produces a single fact out of a last node, which is then distributed
    -- over the outgoing edges.
    distributeXfer :: Edges n => (n O C -> f -> f) -> (n O C -> f -> FactBase f)
    distributeXfer xfer n f = mkFactBase [ (l, xfer n f) | l <- successors n ]
    
    -- | This utility function handles a common case in which a transfer function
    -- for a last node takes the incoming fact unchanged and simply distributes
    -- that fact over the outgoing edges.
    distributeFact :: Edges n => n O C -> f -> FactBase f

    -- | Function 'graphMapBlocks' enables a change of representation of blocks,
    -- nodes, or both.  It lifts a polymorphic block transform into a polymorphic
    -- graph transform.  When the block representation stabilizes, a similar
    -- function should be provided for blocks.
    graphMapBlocks :: forall block n block' n' e x .
                      (forall e x . block n e x -> block' n' e x)
                   -> (Graph' block n e x -> Graph' block' n' e x)

    postorder_dfs :: Edges (block n) => Graph' block n O x -> [block n C C]

  There are quite a few other variations related to depth-first traversal.


  There is a new module Compiler.Hoopl.Pointed, which uses GADTs to
  enable you to add a Top or Bot element to a lattice, or both, all
  using the same type.  (Types 'WithBot' and 'WithTop' in XUtil,
  exported by Compiler.Hoopl, do similar jobs, but I think they are
  inferior.  Your opinion is solicited.)

  I added a function showGraph to print Graphs.  Right now it requires a
  polymorphic node-showing function as argument. When we change the
  Block representation we may get enough static type information that we
  can simply have an instance declaration for 

    instance (Show n C O, Show n O O, Show n O C) => Show (Graph n e x)

  At present, I don't see how to achieve such a declaration.


  John added new functions 'debugFwdJoins' and 'debugBwdJoins' to extend
  passes with debugging information.

  We added primed versions of the analyzeAndRewrite functions, which
  operate on Graph, not Body.  Recommended, at least for first-timers.

  Not all maps keyed by Label are FactBases, so there is now a new set
  of names of functions to manipulate LabelMaps that do not contain
  dataflow facts.



  Implementation changes
  ----------------------
  Split pass and rewrite-function combinators into Compiler.Hoopl.Combinators.

  Changed order of blocks for forward and backward analysis.
  These changes have not been tested, because we don't have a true
  regression suite yet.

  Graph and Body types now have more polymorphic variants Graph' and Body'.

  Lots of experiments with zippers.



  Changes ahead
  -------------
  ForwardTransfer will become an abstract type, and clients will have
  two ways to create ForwardTransfers: as now, with a single,
  polymorphic transfer function; or with a triple of monomorphic
  transfer functions.  The implementation will use monomorphic
  functions, which will enable more useful combinators on passes,
  including adding more debugging information and enabling us to combine
  passes. 

  Perhaps we should provide splicing and 'addBlocks' on Graph?

  Change of block representation to have three monomorphic unit
  constructors and one polymorphic concatenation constructor.

  Graph body to be represented by a finite map; add functions to check
  for duplicate labels.

3.7.12.1

  - Added a bunch of zipper experiments.
  - Existing clients should not be affected.


3.7.12.0

  - More expressive debugging support
  - retract arfGraph and normalization; export analyzeAndRewriterFwd'

3.7.11.1

  - Expose arfGraph and normalization functions

3.7.11.0

  - Debugging support

3.7.8.0

  - Rationalized AGraph splicing functions.

3.7.7.0

  - Restrict clients so they see much less, including hiding
    the value constructors for Body.


