src/Type/Fragment.hs · elk

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elk/src/Type/Fragment.hs

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1{-# OPTIONS_GHC -Wall #-}

2module Type.Fragment where

4import qualified Data.List as List

5import qualified Data.Map as Map

7import Type.Type

10data Fragment = Fragment

11 { typeEnv :: Map.Map String Type

12 , vars :: [Variable]

13 , typeConstraint :: TypeConstraint

14 }

17emptyFragment :: Fragment

18emptyFragment =

19 Fragment Map.empty [] CTrue

22joinFragment :: Fragment -> Fragment -> Fragment

23joinFragment f1 f2 =

24 Fragment

25 { typeEnv =

26 Map.union (typeEnv f1) (typeEnv f2)

28 , vars =

29 vars f1 ++ vars f2

31 , typeConstraint =

32 typeConstraint f1 /\ typeConstraint f2

33 }

36joinFragments :: [Fragment] -> Fragment

37joinFragments =

38 List.foldl' (flip joinFragment) emptyFragment

41toScheme :: Fragment -> Scheme Type Variable

42toScheme fragment =

43 Scheme [] (vars fragment) (typeConstraint fragment) (typeEnv fragment)