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|
module Main where
import Data.Char
import Data.List (isPrefixOf, isSuffixOf)
import Data.Map (Map, (!))
import qualified Data.Map as M
import Debug.Trace (trace, traceShow)
import System.Environment (getArgs)
import Utils
getFilename [] = error "empty argument list"
getFilename (f : fs) = f
data LWord
= LSymbol String
| LInteger Integer
| LFloat Double
| LBool Bool
| LVariable String
| LPhrase [LWord]
deriving (Show, Eq)
reprWord (LSymbol a) = a
reprWord (LInteger a) = show a
reprWord (LFloat a) = show a
reprWord (LBool a) = show a
reprWord (LVariable a) = a
reprWord (LPhrase a) = "P[ " ++ unwords (map reprWord a) ++ " ]"
data LState = LState
{ lDict :: Map String LWord,
lStack :: [LWord],
lPhraseDepth :: Int,
lDefs :: Map String [LWord],
lSource :: [LWord]
}
deriving (Show)
evalMode state = lPhraseDepth state == 0
debugState state = do
putStrLn $ "stack: " ++ unwords (map reprWord (lStack state))
putStrLn $ "source: " ++ unwords (map reprWord (lSource state))
putStrLn $ "defs: " ++ unwords (M.keys (lDefs state))
putStrLn $ "dict: " ++ unwords (M.keys (lDict state))
putStrLn $ "lPhraseDepth: " ++ show (lPhraseDepth state)
putStrLn ""
parseWord rawStr
| isIntStr rawStr = LInteger (read rawStr)
| isFloatStr rawStr = LFloat $ read rawStr
| "$" `isPrefixOf` rawStr = LVariable $ tail rawStr
| otherwise = LSymbol rawStr
parseSource source = source $> words .> map parseWord
interpretSource :: LState -> IO ()
interpretSource LState {lSource = []} = putStrLn "done"
interpretSource state@LState {lSource = (word : rest)} = do
newState <- interpretWord state {lSource = rest} word
-- putStrLn $ "[debug] processed " ++ show word ++ ", newState ="
-- debugState newState
interpretSource newState
interpretWord :: LState -> LWord -> IO LState
-- non-nestable structures
interpretWord state@LState {lStack = stack, lPhraseDepth = phraseDepth} word@(LSymbol "define") =
pure $
state
{ lPhraseDepth = phraseDepth + 1,
lStack = word : stack
}
interpretWord state@LState {lDefs = defs, lStack = stack, lPhraseDepth = phraseDepth} word@(LSymbol ";") =
let defineSpan = takeWhile (\word -> word /= LSymbol "define") stack
newStack = dropWhile (\word -> word /= LSymbol "define") stack $> tail
((LSymbol identifier) : body) = reverse defineSpan
newDefs = M.insert identifier body defs
in pure $
state
{ lPhraseDepth = phraseDepth - 1,
lDefs = newDefs,
lStack = newStack
}
-- words that simply move from source to stack
interpretWord state@LState {lStack = stack} word@(LInteger _) = pure $ state {lStack = word : stack}
interpretWord state@LState {lStack = stack} word@(LFloat _) = pure $ state {lStack = word : stack}
interpretWord state@LState {lStack = stack} word@(LBool _) = pure $ state {lStack = word : stack}
interpretWord state@LState {lStack = stack} word@(LVariable _) = pure $ state {lStack = word : stack}
interpretWord state@LState {lStack = stack} word@(LPhrase _) = pure $ state {lStack = word : stack}
-- phrase markers are always evaled
interpretWord state@LState {lStack = stack, lPhraseDepth = phraseDepth} word@(LSymbol "[") =
pure $ state {lPhraseDepth = phraseDepth + 1, lStack = word : stack}
interpretWord state@LState {lStack = stack, lPhraseDepth = phraseDepth} word@(LSymbol "]") =
let (phrase, stack') = break (== LSymbol "[") stack
newStack = LPhrase phrase : tail stack'
in pure $ state {lPhraseDepth = phraseDepth - 1, lStack = newStack}
-- definition lookup
interpretWord state@LState {lDefs = defs, lDict = dict, lSource = source, lPhraseDepth = phraseDepth, lStack = stack} word@(LSymbol symbol)
| phraseDepth == 0 =
case M.lookup symbol defs of
Just body -> pure $ state {lSource = body ++ source}
Nothing ->
case symbol of
"dup" -> pure $ state {lStack = head stack : stack}
"drop" -> pure $ state {lStack = tail stack}
"noop" -> pure state
"true" -> pure $ state {lStack = LBool True : stack}
"false" -> pure $ state {lStack = LBool False : stack}
"not" ->
let (LBool a : stack') = stack
in pure $ state {lStack = LBool (not a) : stack'}
"float" ->
let (LInteger a : stack') = stack
in pure $ state {lStack = LFloat (fromIntegral a) : stack'}
"round" ->
let (LFloat a : stack') = stack
in pure $ state {lStack = LInteger (round a) : stack'}
"!" ->
let (LVariable a : b : stack') = stack
newDict = M.insert a b dict
in pure $ state {lDict = newDict, lStack = stack'}
"@" ->
let (LVariable a : stack') = stack
lookupWord = dict ! a
in pure $ state {lStack = lookupWord : stack'}
"." -> do
let (a : stack') = stack
putStrLn $ reprWord a
pure $ state {lStack = stack'}
"?" -> do
let (LVariable a : stack') = stack
let lookupWord = dict ! a
putStrLn $ reprWord lookupWord
pure $ state {lStack = stack'}
"+" ->
let (a : b : stack') = stack
result = lAddNumbers a b
in pure $ state {lStack = result : stack'}
"*" ->
let (a : b : stack') = stack
result = lMultiplyNumbers a b
in pure $ state {lStack = result : stack'}
"eq?" ->
let (a : b : stack') = stack
in pure $ state {lStack = LBool (a == b) : stack'}
"cond" ->
let (fb : tb : (LBool cond) : stack') = stack
LPhrase branch = if cond then tb else fb
newSource = reverse branch ++ source
in pure $ state {lStack = stack', lSource = newSource}
_ -> error $ "[error] not defined: " ++ symbol
| otherwise = pure $ state {lStack = word : stack}
-- error
-- interpretWord state other = error $ "[error] runtime error at " ++ show other ++ "\ninterpreter state at time of error:\n" ++ show state
lAddNumbers (LInteger a) (LInteger b) = LInteger (a + b)
lAddNumbers (LFloat a) (LFloat b) = LFloat (a + b)
lAddNumbers a b = error $ "[error] sum not defined for " ++ show a ++ ", " ++ show b
lMultiplyNumbers (LInteger a) (LInteger b) = LInteger (a * b)
lMultiplyNumbers (LFloat a) (LFloat b) = LFloat (a * b)
lMultiplyNumbers a b = error $ "[error] product not defined for " ++ show a ++ ", " ++ show b
main :: IO ()
main = do
args <- getArgs
let filename = getFilename args
putStrLn $ "[info] executing file " ++ filename
source <- readFile filename
-- putStrLn source
let sourceWoComments = source $> lines .> filter (\line -> not ("--" `isPrefixOf` line)) .> unlines
let parsed = parseSource sourceWoComments
-- putStrLn $ "[info] parsed words:\n" ++ show parsed
putStrLn "[info] interpreter output:"
let initialState =
LState
{ lDict = M.empty,
lStack = [],
lPhraseDepth = 0,
lDefs = M.empty,
lSource = parsed
}
interpretSource initialState
|
