git.iko.soy/elk
on d92ac79 help sign in
elk/compiler/SourceSyntax/Type.hs
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1{-# OPTIONS_GHC -Wall #-}
2module SourceSyntax.Type where
4import Data.Binary
5import qualified Data.Map as Map
6import qualified SourceSyntax.Helpers as Help
7import Control.Applicative ((<$>), (<*>))
8import SourceSyntax.PrettyPrint
9import Text.PrettyPrint as P
11data Type = Lambda Type Type
12 | Var String
13 | Data String [Type]
14 | Record [(String,Type)] (Maybe String)
15 deriving (Eq, Show)
17fieldMap :: [(String,a)] -> Map.Map String [a]
18fieldMap fields =
19 foldl (\r (x,t) -> Map.insertWith (++) x [t] r) Map.empty fields
21recordOf :: [(String,Type)] -> Type
22recordOf fields = Record fields Nothing
24listOf :: Type -> Type
25listOf t = Data "_List" [t]
27tupleOf :: [Type] -> Type
28tupleOf ts = Data ("_Tuple" ++ show (length ts)) ts
31instance Pretty Type where
32 pretty tipe =
33 case tipe of
34 Lambda _ _ -> P.sep [ t, P.sep (map (P.text "->" <+>) ts) ]
35 where t:ts = collectLambdas tipe
36 Var x -> P.text x
37 Data "_List" [t] -> P.brackets (pretty t)
38 Data name tipes
39 | Help.isTuple name -> P.parens . P.sep . P.punctuate P.comma $ map pretty tipes
40 | otherwise -> P.hang (P.text name) 2 (P.sep $ map prettyParens tipes)
41 Record fields ext ->
42 P.braces $ case ext of
43 Nothing -> prettyFields
44 Just x -> P.hang (P.text x <+> P.text "|") 4 prettyFields
45 where
46 prettyField (f,t) = P.text f <+> P.text ":" <+> pretty t
47 prettyFields = commaSep . map prettyField $ fields
49collectLambdas :: Type -> [Doc]
50collectLambdas tipe =
51 case tipe of
52 Lambda arg@(Lambda _ _) body -> P.parens (pretty arg) : collectLambdas body
53 Lambda arg body -> pretty arg : collectLambdas body
54 _ -> [pretty tipe]
56prettyParens :: Type -> Doc
57prettyParens tipe = parensIf needed (pretty tipe)
58 where
59 needed =
60 case tipe of
61 Lambda _ _ -> True
62 Data "_List" [_] -> False
63 Data _ [] -> False
64 Data _ _ -> True
65 _ -> False
67instance Binary Type where
68 put tipe =
69 case tipe of
70 Lambda t1 t2 ->
71 putWord8 0 >> put t1 >> put t2
72 Var x ->
73 putWord8 1 >> put x
74 Data ctor tipes ->
75 putWord8 2 >> put ctor >> put tipes
76 Record fs ext ->
77 putWord8 3 >> put fs >> put ext
79 get = do
80 n <- getWord8
81 case n of
82 0 -> Lambda <$> get <*> get
83 1 -> Var <$> get
84 2 -> Data <$> get <*> get
85 3 -> Record <$> get <*> get
86 _ -> error "Error reading a valid type from serialized string"