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

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