{- |

Module : $Header$

Copyright : (c) Christian Maeder and Uni Bremen 2003-2005

License : similar to LGPL, see HetCATS/LICENSE.txt or LIZENZ.txt

Maintainer : maeder@tzi.de

Stability : experimental

Portability : portable

analysing kinds using a class map

-}

module HasCASL.ClassAna where

import HasCASL.As

import HasCASL.AsUtils

import Common.Id

import HasCASL.Le

import Common.PrettyPrint

import qualified Common.Lib.Map as Map

import Common.Lib.State

import Common.Result

-- * analyse kinds

-- | check the kind and compute the raw kind

anaKindM :: Kind -> ClassMap -> Result RawKind

anaKindM k cm = case k of

ClassKind ci -> if k == universe then return rStar

else case Map.lookup ci cm of

Just (ClassInfo rk _) -> return rk

Nothing -> Result [mkDiag Error "not a class" ci] $ Just rStar

FunKind v k1 k2 ps -> do

rk1 <- anaKindM k1 cm

rk2 <- anaKindM k2 cm

return $ FunKind v rk1 rk2 ps

-- | get minimal function kinds of (class) kind

getFunKinds :: Monad m => ClassMap -> Kind -> m [Kind]

getFunKinds cm k = case k of

FunKind _ _ _ _ -> return [k]

ClassKind c -> case Map.lookup c cm of

Just (ClassInfo _ cs) -> do

ks <- mapM (getFunKinds cm) cs

return $ keepMinKinds cm $ concat ks

_ -> fail $ "not a function kind '" ++ showId c "'"

-- | compute arity from a raw kind

kindArity :: RawKind -> Int

kindArity k =

case k of

ClassKind _ -> 0

FunKind _ _ rk _ -> 1 + kindArity rk

-- | check if a class occurs in one of its super kinds

cyclicClassId :: ClassMap -> ClassId -> Kind -> Bool

cyclicClassId cm ci k =

case k of

FunKind _ k1 k2 _ ->

cyclicClassId cm ci k1 || cyclicClassId cm ci k2

ClassKind cj -> if k == universe then False else

cj == ci || case Map.lookup cj cm of

Nothing -> error "cyclicClassId"

Just info -> any (cyclicClassId cm ci) $ classKinds info

-- * subkinding

-- | keep only minimal elements

keepMins :: (a -> a -> Bool) -> [a] -> [a]

keepMins lt l = case l of

[] -> []

x : r -> let s = filter ( \ y -> not (lt x y)) r

m = keepMins lt s

in if any ( \ y -> lt y x) s then m

else x : m

-- | keep only minimal elements according to 'lesserKind'

keepMinKinds :: ClassMap -> [Kind] -> [Kind]

keepMinKinds cm = keepMins (lesserKind cm)

-- | check subkinding (kinds with variances are greater)

lesserKind :: ClassMap -> Kind -> Kind -> Bool

lesserKind cm k1 k2 = case k1 of

ClassKind c1 -> (case k2 of

ClassKind c2 -> c1 == c2 || if k1 == universe then

False else k2 == universe

_ -> False) ||

case Map.lookup c1 cm of

Just (ClassInfo _ ks) -> any ( \ k -> lesserKind cm k k2) ks

_ -> False

FunKind v1 a1 r1 _ -> case k2 of

FunKind v2 a2 r2 _ -> (case v2 of

InVar -> True

_ -> v1 == v2) && lesserKind cm r1 r2 && lesserKind cm a2 a1

_ -> False

invertVariance :: Variance -> Variance

invertVariance v = case v of

CoVar -> ContraVar

ContraVar -> CoVar

_ -> v

-- * diagnostic messages

-- | create message for different kinds

diffKindDiag :: (PosItem a, PrettyPrint a) =>

a -> RawKind -> RawKind -> [Diagnosis]

diffKindDiag a k1 k2 =

[ Diag Error

("incompatible kind of: " ++ showPretty a "" ++ expected k1 k2)

$ getRange a ]

-- | check if raw kinds are equal

checkKinds :: (PosItem a, PrettyPrint a) =>

a -> RawKind -> RawKind -> [Diagnosis]

checkKinds p k1 k2 =

if k1 == k2 then []

else diffKindDiag p k1 k2

-- | analyse class decls

anaClassDecls :: ClassDecl -> State Env ClassDecl

anaClassDecls (ClassDecl cls k ps) =

do cm <- gets classMap

let Result ds (Just rk) = anaKindM k cm

addDiags ds

let ak = if null ds then k else universe

mapM_ (addClassDecl rk ak) cls

return $ ClassDecl cls ak ps

-- | store a class

addClassDecl :: RawKind -> Kind -> ClassId -> State Env ()

-- check with merge

addClassDecl rk kind ci =

if showId ci "" == "Type" then

do addDiags [mkDiag Warning

"void universe class declaration" ci]

else do

cm <- gets classMap

tm <- gets typeMap

tvs <- gets localTypeVars

case Map.lookup ci tm of

Just _ -> addDiags [mkDiag Error "class name already a type" ci]

Nothing -> do

case Map.lookup ci tvs of

Just _ ->

addDiags [mkDiag Error "class name already a type variable" ci]

Nothing -> do

case Map.lookup ci cm of

Nothing ->

putClassMap $ Map.insert ci (ClassInfo rk [kind]) cm

Just (ClassInfo ork superClasses) -> do

let ds = checkKinds ci rk ork

addDiags ds

if null ds then

if cyclicClassId cm ci kind then

addDiags [mkDiag Error "cyclic class" ci]

else if any (\ k -> lesserKind cm k kind) superClasses

then addDiags [mkDiag Warning "unchanged class" ci]

else do addDiags [mkDiag Hint

"refined class" ci]

putClassMap $ Map.insert ci

(ClassInfo ork $ keepMinKinds cm $

kind : superClasses) cm

else return ()