module Transducer (
      Transducer
    , fromList
    , run
  ) where

import Stream (Stream)
import Graph (Graph, editLabel, open, rewind, singleton, weave)

type Transducer input output = Graph input [output]

empty :: Transducer input output
empty = open $ singleton []

add :: Ord input => Transducer input output -> ([input], output) -> Transducer input output
add transducer (path, output) =
  rewind $ editLabel (weave transducer path) (output:)

fromList :: Ord input => [([input], output)] -> Transducer input output
fromList = foldl add empty

run :: Ord input => Transducer input output -> Stream input -> Stream output
run = undefined