module Main where

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import           Paths_calculator          (version)

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import           Calculator.Evaluator.Base (evaluate)
import           Calculator.Prim.Expr      (Bindings, defBinds)

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import           Data.Version              (showVersion)
import           System.Console.Haskeline

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type Repl a = InputT IO a

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repl :: Bindings -> Repl ()
repl b = do
  input <- getInputLine "calc> "
  case input of
    Nothing  -> return ()
    Just inp -> case evaluate b inp of
                  Left s   -> outputStrLn s >> repl b
                  Right b' -> repl b'

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main :: IO ()
main = do
  putStrLn $ "calculator, version "
               ++ showVersion version
               ++ ". Use :? for help"
  runInputT defaultSettings (repl defBinds)

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