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semantic/src/Analysis/IdentifierName.hs
2018-03-08 09:33:12 -08:00

60 lines
2.3 KiB
Haskell

{-# LANGUAGE DataKinds, MultiParamTypeClasses, ScopedTypeVariables, TypeFamilies, TypeOperators, UndecidableInstances #-}
module Analysis.IdentifierName
( IdentifierName(..)
, IdentifierLabel(..)
, identifierLabel
) where
import Data.Abstract.FreeVariables
import Data.Aeson
import Data.JSON.Fields
import Data.Term
import Data.Text.Encoding (decodeUtf8)
import Prologue
import qualified Data.Syntax
-- | Compute a 'IdentifierLabel' label for a 'Term'.
identifierLabel :: IdentifierName syntax => TermF syntax a b -> Maybe IdentifierLabel
identifierLabel (In _ s) = IdentifierLabel <$> identifierName s
newtype IdentifierLabel = IdentifierLabel ByteString
deriving (Show)
instance ToJSONFields IdentifierLabel where
toJSONFields (IdentifierLabel s) = [ "name" .= decodeUtf8 s ]
-- | A typeclass to retrieve the name of syntax identifiers.
--
-- This typeclass employs the Advanced Overlap techniques designed by Oleg Kiselyov & Simon Peyton Jones: https://wiki.haskell.org/GHC/AdvancedOverlap; see also src/Analysis/Declaration.hs for discussion of the details of the mechanism.
class IdentifierName syntax where
identifierName :: syntax a -> Maybe ByteString
instance (IdentifierNameStrategy syntax ~ strategy, IdentifierNameWithStrategy strategy syntax) => IdentifierName syntax where
identifierName = identifierNameWithStrategy (Proxy :: Proxy strategy)
class CustomIdentifierName syntax where
customIdentifierName :: syntax a -> Maybe ByteString
instance Apply IdentifierName fs => CustomIdentifierName (Union fs) where
customIdentifierName = apply (Proxy :: Proxy IdentifierName) identifierName
instance CustomIdentifierName Data.Syntax.Identifier where
customIdentifierName (Data.Syntax.Identifier name) = Just (friendlyName name)
data Strategy = Default | Custom
type family IdentifierNameStrategy syntax where
IdentifierNameStrategy (Union _) = 'Custom
IdentifierNameStrategy Data.Syntax.Identifier = 'Custom
IdentifierNameStrategy syntax = 'Default
class IdentifierNameWithStrategy (strategy :: Strategy) syntax where
identifierNameWithStrategy :: proxy strategy -> syntax a -> Maybe ByteString
instance IdentifierNameWithStrategy 'Default syntax where
identifierNameWithStrategy _ _ = Nothing
instance (CustomIdentifierName syntax) => IdentifierNameWithStrategy 'Custom syntax where
identifierNameWithStrategy _ = customIdentifierName