add getline putstr, and fix putstr to flush the handle
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1 changed files with 19 additions and 5 deletions
24
interp.hs
24
interp.hs
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@ -1,6 +1,6 @@
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import Control.Monad.State (State, runState, evalState, get, put)
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import qualified Data.Map as M
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import System.IO (Handle, hPutChar, hPutStr, stdout)
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import System.IO (Handle, hPutStr, hGetLine, hFlush, stdout, stdin)
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import System.IO.Unsafe (unsafePerformIO)
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import AST
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import Parser (parseProgram)
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@ -26,6 +26,10 @@ type InterpState = State ([Handle], Env) -- interpreter state (open handles, glo
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(StrV l) +$ (StrV r) = StrV (l ++ r)
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l +$ r = error $ "cannot + " ++ show l ++ " and " ++ show r
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-- these are pretty nasty and instead of using unsafePerformIO
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-- we could throw eval, etc. into StateT with IO instead, but then
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-- everything would be in IO.
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_putstr (StrV str) = do
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(handles,_) <- get
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let stdout_s = head handles
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@ -33,13 +37,23 @@ _putstr (StrV str) = do
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return $ seq io UnitV
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where
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{-# NOINLINE unsafe_putstr #-}
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unsafe_putstr h s = unsafePerformIO $ hPutStr h s
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unsafe_putstr h s = unsafePerformIO $ hPutStr h s >> hFlush h
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initialState = ([stdout],
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_getline UnitV = do
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(handles,_) <- get
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let stdin_s = handles !! 1
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let str = unsafe_getline stdin_s
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return $ seq () $ StrV str
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where
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{-# NOINLINE unsafe_getline #-}
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unsafe_getline h = unsafePerformIO $ hGetLine h
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initialState = ([stdout, stdin],
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M.fromList [("id", FnV [(VarP "x", [Var "x"])]),
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("stdout", StreamV 0),
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("putstr", Builtin $ BIF _putstr),
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("hw", StrV "Hello, World!\n")])
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("putstrln", Builtin $ BIF (\x -> _putstr $ x +$ StrV "\n")),
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("getline", Builtin $ BIF _getline)])
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eval :: AST -> InterpState Value
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@ -152,7 +166,7 @@ main = do
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print $ evalProgram prg4
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print $ evalString "f() -> 5+2. f()."
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print $ evalString "f([x, y, z]) -> z. f([1, 2, 3])."
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print $ evalString "putstr(hw). putstr(hw). putstr(hw)."
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print $ evalString "putstrln(getline()). putstrln(getline())."
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where
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prg = [Def "x" (IntConst 5),
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Def "y" (IntConst 3),
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