{- |

Module : $Header$

Copyright : (c) Christian Maeder and Uni Bremen 2002-2005

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

Maintainer : maeder@tzi.de

Stability : provisional

Portability : non-portable (MonadState)

analyse alternatives of data types

-}

module HasCASL.DataAna where

import Data.Maybe

import qualified Common.Lib.Map as Map

import qualified Common.Lib.Set as Set

import Common.Id

import Common.Result

import Common.AS_Annotation

import HasCASL.As

import HasCASL.Le

import HasCASL.TypeAna

import HasCASL.AsUtils

import HasCASL.Builtin

import HasCASL.Unify

-- | description of polymorphic data types

data DataPat = DataPat Id [TypeArg] RawKind Type

-- * creating selector equations

mkSelId :: Range -> String -> Int -> Int -> Id

mkSelId p str n m = mkId

[Token (str ++ "_" ++ show n ++ "_" ++ show m) p]

mkSelVar :: Int -> Int -> Type -> VarDecl

mkSelVar n m ty = VarDecl (mkSelId (getRange ty) "x" n m) ty Other nullRange

genTuple :: Int -> Int -> [Selector] -> [VarDecl]

genTuple _ _ [] = []

genTuple n m (Select _ ty _ : sels) =

mkSelVar n m ty : genTuple n (m + 1) sels

genSelVars :: Int -> [[Selector]] -> [[VarDecl]]

genSelVars _ [] = []

genSelVars n (ts:sels) =

genTuple n 1 ts : genSelVars (n + 1) sels

makeSelTupleEqs :: DataPat -> Term -> Int -> Int -> [Selector] -> [Named Term]

makeSelTupleEqs dt@(DataPat _ tArgs _ rt) ct n m (Select mi ty p : sels) =

let sc = TypeScheme tArgs (getSelType rt p ty) nullRange in

(case mi of

Just i -> let

vt = QualVar $ mkSelVar n m ty

eq = mkEqTerm eqId nullRange (mkApplTerm (mkOpTerm i sc) [ct]) vt

in [NamedSen ("ga_select_" ++ show i) True eq]

_ -> [])

++ makeSelTupleEqs dt ct n (m + 1) sels

makeSelTupleEqs _ _ _ _ [] = []

makeSelEqs :: DataPat -> Term -> Int -> [[Selector]] -> [Named Term]

makeSelEqs dt ct n (sel:sels) =

makeSelTupleEqs dt ct n 1 sel

++ makeSelEqs dt ct (n + 1) sels

makeSelEqs _ _ _ _ = []

makeAltSelEqs :: DataPat -> AltDefn -> [Named Term]

makeAltSelEqs dt@(DataPat _ args _ rt) (Construct mc ts p sels) =

case mc of

Nothing -> []

Just c -> let sc = TypeScheme args (getConstrType rt p ts) nullRange

newSc = sc

vars = genSelVars 1 sels

as = map ( \ vs -> mkTupleTerm (map QualVar vs) nullRange) vars

ct = mkApplTerm (mkOpTerm c newSc) as

in map (mapNamed (mkForall (map GenTypeVarDecl args

++ map GenVarDecl (concat vars))))

$ makeSelEqs dt ct 1 sels

makeDataSelEqs :: DataEntry -> Type -> [Named Sentence]

makeDataSelEqs (DataEntry _ i _ args rk alts) rt =

map (mapNamed Formula) $

concatMap (makeAltSelEqs $ DataPat i args rk rt) alts

-- * analysis of alternatives

anaAlts :: [DataPat] -> DataPat -> [Alternative] -> TypeEnv -> Result [AltDefn]

anaAlts tys dt alts te =

do l <- mapM (anaAlt tys dt te) alts

Result (checkUniqueness $ catMaybes $

map ( \ (Construct i _ _ _) -> i) l) $ Just ()

return l

anaAlt :: [DataPat] -> DataPat -> TypeEnv -> Alternative

-> Result AltDefn

anaAlt _ _ te (Subtype ts _) =

do l <- mapM ( \ t -> anaStarTypeM t te) ts

return $ Construct Nothing (map snd l) Partial []

anaAlt tys dt te (Constructor i cs p _) =

do newCs <- mapM (anaComps tys dt te) cs

let sels = map snd newCs

Result (checkUniqueness $ catMaybes $

map ( \ (Select s _ _) -> s ) $ concat sels) $ Just ()

return $ Construct (Just i) (map fst newCs) p sels

anaComps :: [DataPat] -> DataPat -> TypeEnv -> [Component]

-> Result (Type, [Selector])

anaComps tys rt te cs =

do newCs <- mapM (anaComp tys rt te) cs

return (mkProductType (map fst newCs) nullRange, map snd newCs)

anaComp :: [DataPat] -> DataPat -> TypeEnv -> Component

-> Result (Type, Selector)

anaComp tys rt te (Selector s p t _ _) =

do ct <- anaCompType tys rt t te

return (ct, Select (Just s) ct p)

anaComp tys rt te (NoSelector t) =

do ct <- anaCompType tys rt t te

return (ct, Select Nothing ct Partial)

anaCompType :: [DataPat] -> DataPat -> Type -> TypeEnv -> Result Type

anaCompType tys (DataPat _ tArgs _ _) t te = do

(_, ct) <- anaStarTypeM t te

let ds = unboundTypevars True tArgs ct

if null ds then return () else Result ds Nothing

mapM (checkMonomorphRecursion ct te) tys

return $ generalize tArgs ct

checkMonomorphRecursion :: Type -> TypeEnv -> DataPat -> Result ()

checkMonomorphRecursion t te (DataPat i _ _ rt) =

if occursIn (typeMap te) i t then

if lesserType te t rt || lesserType te rt t then return ()

else Result [Diag Error ("illegal polymorphic recursion"

++ expected rt t) $ getRange t] Nothing

else return ()

occursIn :: TypeMap -> TypeId -> Type -> Bool

occursIn tm i = any (relatedTypeIds tm i) . Set.toList . idsOf (const True)

relatedTypeIds :: TypeMap -> TypeId -> TypeId -> Bool

relatedTypeIds tm i1 i2 =

not $ Set.null $ Set.intersection (allRelIds tm i1) $ allRelIds tm i2

allRelIds :: TypeMap -> TypeId -> Set.Set TypeId

allRelIds tm i = Set.union (superIds tm i) $ subIds tm i

subIds :: TypeMap -> Id -> Set.Set Id

subIds tm i = foldr ( \ j s ->

if Set.member i $ superIds tm j then

Set.insert j s else s) Set.empty $ Map.keys tm