{-# LANGUAGE TemplateHaskell #-}
module Symantic.Parser.Automaton
 ( module Symantic.Parser.Automaton
 , module Symantic.Parser.Automaton.Instructions
 , module Symantic.Parser.Automaton.Dump
 , module Symantic.Parser.Automaton.Eval
 , module Symantic.Parser.Automaton.Input
 ) where
import Symantic.Parser.Automaton.Instructions
import Symantic.Parser.Automaton.Dump
import Symantic.Parser.Automaton.Eval
import Data.Either (Either(..))

import Data.Function ((.))
-- import Data.Char (Char)
import Data.Ord (Ord)
import Language.Haskell.TH (CodeQ)
import Symantic.Parser.Automaton.Input
import Symantic.Parser.Grammar
import Text.Show (Show)
import qualified Language.Haskell.TH.Syntax as TH

type Parser inp =
  ObserveSharing TH.Name
                 (OptimizeComb TH.Name
                               (Automaton (inp)))

automaton :: forall inp repr a.
  Ord (InputToken inp) =>
  Show (InputToken inp) =>
  TH.Lift (InputToken inp) =>
  -- InputToken inp ~ Char =>
  Executable repr =>
  Readable repr (InputToken inp) =>
  Grammar (Automaton inp) =>
  Parser inp a ->
  repr inp '[] ('Succ 'Zero) a
automaton = runAutomaton . optimizeComb . observeSharing

runParser :: forall inp a.
  Ord (InputToken inp) =>
  Show (InputToken inp) =>
  TH.Lift (InputToken inp) =>
  -- InputToken inp ~ Char =>
  Input inp =>
  Readable Eval (InputToken inp) =>
  Parser inp a ->
  CodeQ (inp -> Either (ParsingError inp) a)
runParser p = [|| \input -> $$(eval [||input||] (automaton p)) ||]