39 lines
1.2 KiB
Haskell
39 lines
1.2 KiB
Haskell
import Lox.Scanner
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import Lox.Parser
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import Lox.Interpreter
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import System.IO
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import System.Environment
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run :: String -> IO ()
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run source = do
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let tokensMaybe = scanTokensFromSource source
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case tokensMaybe of
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Left UnexpectedCharacterError -> putStrLn "Unexpected character"
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Right tokens -> do
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let stmtMaybe = parse tokens
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case stmtMaybe of
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Left (SyntaxError s) -> putStrLn s
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Right statements -> runStatements statements
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runEval :: String -> IO ()
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runEval source = do
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let tokensMaybe = scanTokensFromSource source
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object <- case tokensMaybe of
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Left UnexpectedCharacterError -> putStrLn "Unexpected character" >> return NullObject
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Right tokens -> do
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let exprMaybe = parseExpression tokens
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case exprMaybe of
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Left (SyntaxError s) -> putStrLn s >> return NullObject
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Right statements -> eval statements
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print object
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repl :: IO ()
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repl = putStr ">> " >> hFlush stdout >> getLine >>= runEval
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main :: IO ()
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main = getArgs >>= fs
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fs :: [String] -> IO ()
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fs [] = repl
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fs [s] = readFile s >>= run
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fs _ = putStrLn "Usage: lox [file]"
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