git.iko.soy/elk
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elk/src/Type/Inference.hs
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1module Type.Inference where
3import qualified Data.Map as Map
5import qualified Type.Type as T
6import qualified Type.Environment as Env
7import qualified Type.Constrain.Expression as TcExpr
8import qualified Type.Solve as Solve
10import qualified AST.Annotation as A
11import AST.Module as Module
12import AST.Type (CanonicalType)
13import qualified AST.Variable as Var
14import Text.PrettyPrint
15import qualified Type.State as TS
16import qualified Type.ExtraChecks as Check
17import Control.Arrow (first, second)
18import Control.Monad.State (execStateT, forM)
19import Control.Monad.Error (ErrorT, runErrorT, liftIO, throwError)
21import System.IO.Unsafe -- Possible to switch over to the ST monad instead of
22 -- the IO monad. I don't think that'd be worthwhile.
25infer :: Interfaces -> CanonicalModule -> Either [Doc] (Map.Map String CanonicalType)
26infer interfaces modul =
27 unsafePerformIO $ runErrorT $
28 do (header, constraint) <- genConstraints interfaces modul
30 state <- liftIO $ execStateT (Solve.solve constraint) TS.initialState
32 () <- case TS.sHint state of
33 hints@(_:_) -> throwError hints
34 [] -> return ()
36 let header' = Map.delete "::" header
37 types = Map.difference (TS.sSavedEnv state) header'
39 Check.effectTypes types
42genConstraints
43 :: Interfaces
44 -> CanonicalModule
45 -> ErrorT [Doc] IO (Env.TypeDict, T.TypeConstraint)
46genConstraints interfaces modul =
47 do env <- liftIO $ Env.initialEnvironment (canonicalizeAdts interfaces modul)
49 ctors <- forM (Map.keys (Env.constructor env)) $ \name -> do
50 (_, vars, args, result) <- liftIO $ Env.freshDataScheme env name
51 return (name, (vars, foldr (T.==>) result args))
53 importedVars <- mapM (canonicalizeValues env) (Map.toList interfaces)
55 let allTypes = concat (ctors : importedVars)
56 vars = concatMap (fst . snd) allTypes
57 header = Map.map snd (Map.fromList allTypes)
58 environ = A.noneNoDocs . T.CLet [ T.Scheme vars [] (A.noneNoDocs T.CTrue) header ]
60 fvar <- liftIO $ T.variable T.Flexible
61 c <- TcExpr.constrain env (program (body modul)) (T.varN fvar)
62 return (header, environ c)
65canonicalizeValues
66 :: Env.Environment
67 -> (Module.Name, Interface)
68 -> ErrorT [Doc] IO [(String, ([T.Variable], T.Type))]
69canonicalizeValues env (moduleName, iface) =
70 forM (Map.toList (iTypes iface)) $ \(name,tipe) ->
71 do tipe' <- Env.instantiateType env tipe Map.empty
72 return (Module.nameToString moduleName ++ "." ++ name, tipe')
75canonicalizeAdts :: Interfaces -> CanonicalModule -> [CanonicalAdt]
76canonicalizeAdts interfaces modul =
77 localAdts ++ importedAdts
78 where
79 localAdts :: [CanonicalAdt]
80 localAdts = format (Module.names modul, datatypes (body modul))
82 importedAdts :: [CanonicalAdt]
83 importedAdts = concatMap (format . second iAdts) (Map.toList interfaces)
85 format :: (Module.Name, Module.ADTs) -> [CanonicalAdt]
86 format (home, adts) =
87 map canonical (Map.toList adts)
88 where
89 canonical :: (String, AdtInfo String) -> CanonicalAdt
90 canonical (name, (tvars, ctors)) =
91 ( toVar name
92 , (tvars, map (first toVar) ctors)
93 )
95 toVar :: String -> Var.Canonical
96 toVar = Var.Canonical (Var.Module home)