elm/compiler/Type/Inference.hs

55 lines
2.2 KiB
Haskell

module Type.Inference where
import qualified Data.Map as Map
import qualified Type.Type as T
import qualified Type.Environment as Env
import qualified Type.Constrain.Expression as TcExpr
import qualified Type.Constrain.Declaration as TcDecl
import qualified Type.Solve as Solve
import SourceSyntax.Module as Module
import qualified SourceSyntax.Expression as Expr
import SourceSyntax.Location (Located, noneNoDocs)
import SourceSyntax.PrettyPrint
import SourceSyntax.Type (Type)
import Text.PrettyPrint
import qualified Type.State as TS
import Type.ExtraChecks (extraChecks)
import Control.Monad.State
import Control.Arrow (second)
import Transform.SortDefinitions as Sort
import qualified Data.Traversable as Traverse
import System.IO.Unsafe -- Possible to switch over to the ST monad instead of
-- the IO monad. I don't think that'd be worthwhile.
infer :: Interfaces -> MetadataModule t v -> Either [Doc] (Map.Map String Type)
infer interfaces modul = unsafePerformIO $ do
env <- Env.initialEnvironment
(datatypes modul ++ concatMap iAdts (Map.elems interfaces))
(aliases modul ++ concatMap iAliases (Map.elems interfaces))
ctors <- forM (Map.keys (Env.constructor env)) $ \name ->
do (_, vars, args, result) <- Env.freshDataScheme env name
return (name, (vars, foldr (T.==>) result args))
importedVars <-
forM (concatMap (Map.toList . iTypes) $ Map.elems interfaces) $ \(name,tipe) ->
(,) name `fmap` Env.instantiateType env tipe Map.empty
let allTypes = ctors ++ importedVars
vars = concatMap (fst . snd) allTypes
header = Map.map snd (Map.fromList allTypes)
environ = noneNoDocs . T.CLet [ T.Scheme vars [] (noneNoDocs T.CTrue) header ]
fvar <- T.var T.Flexible
constraint <- environ `fmap` TcExpr.constrain env (program modul) (T.VarN fvar)
state <- execStateT (Solve.solve constraint) TS.initialState
case TS.sErrors state of
errors@(_:_) -> Left `fmap` sequence (reverse errors)
[] -> let types = Map.difference (TS.sSavedEnv state) header in
do srcTypes <- Traverse.traverse T.toSrcType types
return $ Right srcTypes