elm/compiler/Type/Inference.hs
Evan Czaplicki a3a7b3ef62 Refactor type environment
Migrate some functions to Environment.hs, add built-in types like _List
and _Tuple2.
2013-07-17 19:29:27 +02:00

41 lines
1.4 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
import qualified SourceSyntax.Expression as Expr
import Text.PrettyPrint
import qualified Type.State as TS
import Control.Monad.State
import Control.Arrow (second)
import Transform.SortDefinitions as Sort
import System.IO.Unsafe -- Possible to switch over to the ST monad instead of
-- the IO monad. Not sure if that'd be worthwhile.
infer :: MetadataModule t v -> Either [Doc] (Map.Map String T.Variable)
infer modul = unsafePerformIO $ do
env <- Env.initialEnvironment (datatypes modul)
var <- T.flexibleVar
ctors <- forM (Map.keys (Env.constructor env)) $ \name ->
do (_, vars, tipe) <- Env.freshDataScheme env name
return (name, (vars, tipe))
let expr = Expr.dummyLet $ defs modul
vars = concatMap (fst . snd) ctors
header = Map.map snd (Map.fromList ctors)
environ = T.CLet [ T.Scheme vars [] T.CTrue header ]
constraint <- environ `fmap` TcExpr.constrain env expr (T.VarN var)
print =<< T.extraPretty constraint
(env,_,_,errors) <- execStateT (Solve.solve constraint) TS.initialState
if null errors
then return $ Right env
else Left `fmap` sequence errors