36 lines
856 B
Haskell
36 lines
856 B
Haskell
module Main (main) where
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import APL.Eval (Val (..), eval, runEval)
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import APL.Parser (parseAPL)
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import System.Environment
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( getArgs,
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getProgName,
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)
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import System.Exit (ExitCode (..), exitWith)
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import System.IO (hPutStrLn, stderr, stdout)
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stringVal :: Val -> String
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stringVal (ValBool b) = show b
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stringVal (ValInt x) = show x
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stringVal ValFun {} = "#<fun>"
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main :: IO ()
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main = do
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args <- getArgs
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case args of
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[fname] -> do
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s <- readFile fname
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case parseAPL fname s of
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Left err -> hPutStrLn stderr err
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Right e -> case runEval (eval e) of
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Left err -> hPutStrLn stderr err
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Right v -> hPutStrLn stdout $ stringVal v
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_ -> do
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prog <- getProgName
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failure $ "Usage: " ++ prog ++ " FILE"
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pure ()
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where
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failure s = do
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hPutStrLn stderr s
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exitWith $ ExitFailure 1
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