[commit: ghc] supercompiler: Comments and commoning-up of InstanceMatching (8b3355f)

Repository : ssh://darcs.haskell.org//srv/darcs/ghc

On branch  : supercompiler

http://hackage.haskell.org/trac/ghc/changeset/8b3355f390e15ca2aa96bdb7fe84d5edf58f1ab1

>---------------------------------------------------------------

commit 8b3355f390e15ca2aa96bdb7fe84d5edf58f1ab1
Author: Max Bolingbroke <[email protected]>
Date:   Tue Apr 24 10:36:18 2012 +0100

    Comments and commoning-up of InstanceMatching

>---------------------------------------------------------------

 compiler/supercompile/Supercompile/Drive/MSG.hs    |   10 +++-------
 compiler/supercompile/Supercompile/Drive/Match.hs  |    7 -------
 .../supercompile/Supercompile/Evaluator/Syntax.hs  |   10 ++++++++++
 3 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/compiler/supercompile/Supercompile/Drive/MSG.hs b/compiler/supercompile/Supercompile/Drive/MSG.hs
index 857bc91..b7f4c36 100644
--- a/compiler/supercompile/Supercompile/Drive/MSG.hs
+++ b/compiler/supercompile/Supercompile/Drive/MSG.hs
@@ -41,6 +41,9 @@ import qualified Data.Set as S
 import qualified Data.Foldable as Foldable
 
 
+-- FIXME: we probably need to enforce the kind invariant explicitly
+
+
 pprTraceSC :: String -> SDoc -> a -> a
 --pprTraceSC _ _ = id
 --pprTraceSC = pprTrace
@@ -368,13 +371,6 @@ msg :: MSGMode -- ^ How to match
 msg mm s_l s_r = runMSG' (msgWithReason mm s_l s_r)
 
 
-data InstanceMatching = NoInstances | InstancesOfGeneralised | AllInstances
-
-mayInstantiate :: InstanceMatching -> Generalised -> Bool
-mayInstantiate NoInstances            _   = False
-mayInstantiate InstancesOfGeneralised gen = gen
-mayInstantiate AllInstances           _   = True
-
 data MSGMatchResult = RightIsInstance   Heap Renaming Stack
                     | RightGivesTypeGen Renaming State Renaming
 
diff --git a/compiler/supercompile/Supercompile/Drive/Match.hs b/compiler/supercompile/Supercompile/Drive/Match.hs
index 82c7000..86c5d42 100644
--- a/compiler/supercompile/Supercompile/Drive/Match.hs
+++ b/compiler/supercompile/Supercompile/Drive/Match.hs
@@ -87,13 +87,6 @@ matchRnEnv2 f x y = mkRnEnv2 (mkInScopeSet (f x `unionVarSet` f y))
 --     mx1 `mplus` mx2 = Match $ unMatch mx1 `mplus` unMatch mx2
 
 
-data InstanceMatching = NoInstances | InstancesOfGeneralised | AllInstances
-
-mayInstantiate :: InstanceMatching -> Generalised -> Bool
-mayInstantiate NoInstances            _   = False
-mayInstantiate InstancesOfGeneralised gen = gen
-mayInstantiate AllInstances           _   = True
-
 data MatchMode = MM {
     matchInstanceMatching :: InstanceMatching,
     matchCommonHeapVars :: InScopeSet
diff --git a/compiler/supercompile/Supercompile/Evaluator/Syntax.hs b/compiler/supercompile/Supercompile/Evaluator/Syntax.hs
index 850ee48..885d019 100644
--- a/compiler/supercompile/Supercompile/Evaluator/Syntax.hs
+++ b/compiler/supercompile/Supercompile/Evaluator/Syntax.hs
@@ -183,6 +183,13 @@ qaToAnswer qa = case qa of Answer a -> Just a; Question _ -> Nothing
 
 type Generalised = Bool
 
+data InstanceMatching = NoInstances | InstancesOfGeneralised | AllInstances
+
+mayInstantiate :: InstanceMatching -> Generalised -> Bool
+mayInstantiate NoInstances            _   = False
+mayInstantiate InstancesOfGeneralised gen = gen
+mayInstantiate AllInstances           _   = True
+
 
 type UnnormalisedState = (Deeds, Heap, Stack, In AnnedTerm)
 type State = (Deeds, Heap, Stack, Anned QA)
@@ -254,6 +261,9 @@ letBound :: In AnnedTerm -> HeapBinding
 letBound in_e = HB LetBound (Right in_e)
 
 -- INVARIANT: the Heap might contain bindings for TyVars as well, but will only map them to lambdaBound/generalised
+-- TODO: when we lambda-abstract over lambdaBounds, we implicitly rely on the fact that the lambdaBound IdInfo will work
+-- out properly (unfortunately lambda-bounds can't be brought into scope all at the same time). We should probably fix
+-- this -- perhaps by zapping all lambdaBound IdInfo when we abstract.
 type PureHeap = M.Map (Out Var) HeapBinding
 data Heap = Heap PureHeap InScopeSet