symantic-grammar/Language/Symantic/Grammar/Source.hs

   1 {-# LANGUAGE DeriveFunctor #-}
   2 {-# LANGUAGE TypeFamilies #-}
   3 module Language.Symantic.Grammar.Source where
   4
   5 import Data.Eq (Eq)
   6 import Data.Ord (Ord)
   7 import Text.Show (Show)
   8 import Data.Functor (Functor)
   9 import Data.Typeable (Typeable)
  10
  11 -- * Class 'Source'
  12 class Source src where
  13         noSource :: src
  14 instance Source () where
  15         noSource = ()
  16
  17 -- ** Class 'SourceInj'
  18 class Source src => SourceInj a src where
  19         sourceInj :: a -> src
  20 instance SourceInj a () where
  21         sourceInj _ = ()
  22
  23 -- ** Type family 'SourceOf'
  24 type family SourceOf a
  25
  26 -- ** Type 'Sourced'
  27 class Source (SourceOf a) => Sourced a where
  28         sourceOf  :: a -> SourceOf a
  29         setSource :: a -> SourceOf a -> a
  30 infixl 5 `setSource`
  31
  32 withSource :: SourceInj src (SourceOf a) => Sourced a => a -> src -> a
  33 withSource a src = a `setSource` sourceInj src
  34
  35 -- ** Type 'Source_Input'
  36 type family Source_Input (src :: *) :: *
  37 type instance Source_Input () = ()
  38
  39 -- ** Type 'Span'
  40 data Span src
  41  =   Span
  42  {   spanBegin :: !src
  43  ,   spanEnd   :: !src
  44  } deriving (Eq, Ord, Show, Typeable)
  45
  46 -- ** Type 'At'
  47 -- | Attach a 'Source' to something.
  48 data At src a
  49  =   At
  50  {   at   :: !src
  51  ,   unAt :: !a
  52  } deriving (Eq, Functor, Ord, Show, Typeable)