implementation module lex
-import Data.Either
-import Data.List
-import StdString
-import System.CommandLine
-import StdFile
-import StdMisc
-from StdFunc import id, const
-import Data.Maybe
-import Control.Applicative
import Control.Monad
-import Control.Monad.State
-import Data.Functor
-from Data.Func import $
-from Text import class Text, instance Text String
-import qualified Text
-
-lexer :: [Char] -> LexerOutput
-lexer _ = undef
+import Data.Either, Data.Maybe, Data.Map, Data.Func
+import StdString
+import StdTuple
+import StdBool
+import StdList
+import StdChar
-instance toString LexerOutput where
- toString (Left l) = "Error: " +++ l
- toString (Right x) = 'Text'.concat (print 0 x)
- where
- print :: Int [Token] -> [String]
- print _ [] = []
- print i [(IdentToken l):rest] = [toString l:print i rest]
- print i [(NumberToken j):rest] = [toString j:print i rest]
- print i [(CharToken c):rest] = ["'":toString c:"'":print i rest]
- print i [VarToken:rest] = ["var":print i rest]
- print i [VoidToken:rest] = ["Void":print i rest]
- print i [ReturnToken:rest] = ["return":print i rest]
- print i [IfToken:rest] = ["if":print i rest]
- print i [ElseToken:rest] = ["else":print i rest]
- print i [WhileToken:rest] = ["while":print i rest]
- print i [TrueToken:rest] = ["True":print i rest]
- print i [FalseToken:rest] = ["False":print i rest]
- print i [BraceOpenToken:rest] = ["(":print i rest]
- print i [BraceCloseToken:rest] = [")":print i rest]
- print i [CBraceOpenToken:rest] = ["{\n":tab (i+1):print (i+1) rest]
- print i [CBraceCloseToken:rest] = ["}\n":tab (i-1):print (i-1) rest]
- print i [SquareOpenToken:rest] = ["[":print i rest]
- print i [SquareCloseToken:rest] = ["]":print i rest]
- print i [CommaToken:rest] = [", ":print i rest]
- print i [ColonToken:rest] = [":":print i rest]
- print i [SColonToken:rest] = [";\n":tab i:print i rest]
- print i [DotToken:rest] = [".":print i rest]
- print i [PlusToken:rest] = [" + ":print i rest]
- print i [DashToken:rest] = [" - ":print i rest]
- print i [StarToken:rest] = [" * ":print i rest]
- print i [SlashToken:rest] = [" / ":print i rest]
- print i [PercentToken:rest] = [" % ":print i rest]
- print i [AssignmentToken:rest] = [" = ":print i rest]
- print i [LesserToken:rest] = [" < ":print i rest]
- print i [BiggerToken:rest] = [" > ":print i rest]
- print i [ExclamationToken:rest] = ["!":print i rest]
- print i [DoubleColonToken:rest] = [" :: ":print i rest]
- print i [LesserEqToken:rest] = [" <= ":print i rest]
- print i [GreaterEqToken:rest] = [" >= ":print i rest]
- print i [EqualsToken:rest] = [" == ":print i rest]
- print i [AmpersandsToken:rest] = [" && ":print i rest]
- print i [PipesToken:rest] = [" || ":print i rest]
- print i [ArrowToken:rest] = [" -> ":print i rest]
+SingleCharTokens :: Map Char TokenValue
+SingleCharTokens = fromList [
+ ('(', BraceOpenToken), (')', BraceCloseToken), ('{', CBraceOpenToken),
+ ('}', CBraceCloseToken), ('[', SquareOpenToken), (']', SquareCloseToken),
+ (',', CommaToken), (':', ColonToken), (';', SColonToken),
+ ('.', DotToken), ('+', PlusToken), ('*', StarToken), ('/', SlashToken),
+ ('%', PercentToken), ('=', AssignmentToken), ('<', LesserToken),
+ ('>', BiggerToken), ('!', ExclamationToken)]
-tab :: Int -> String
-tab 0 = ""
-tab i = "\t" +++ tab (i-1)
+EscapeMap :: Map Char Char
+EscapeMap = fromList [('a', toChar 7), ('b', '\b'), ('f', '\f'), ('n', '\n'),
+ ('r', '\r'), ('t', '\t'), ('v', '\v')]
-lex :: [Char] -> LexerOutput
-lex ['v':'a':'r':rest] = undef
-lex ['V':'o':'i':'d':rest] = undef
-lex ['r':'e':'t':'u':'r':'n':rest] = undef
-lex ['i':'f':rest] = undef
-lex ['e':'l':'s':'e':rest] = undef
-lex ['w':'h':'i':'l':'e':rest] = undef
-lex ['T':'r':'u':'e':rest] = undef
-lex ['F':'a':'l':'s':'e':rest] = undef
-lex [':':':':rest] = undef
-lex ['<':'=':rest] = undef
-lex ['>':'=':rest] = undef
-lex ['=':'=':rest] = undef
-lex ['&':'&':rest] = undef
-lex ['|':'|':rest] = undef
-lex ['-':'>':rest] = undef
-lex ['(':rest] = undef
-lex [')':rest] = undef
-lex ['{':rest] = undef
-lex ['{':rest] = undef
-lex ['[':rest] = undef
-lex [':rest]':rest] = undef
-lex [',':rest] = undef
-lex [':':rest] = undef
-lex [';':rest] = undef
-lex ['.':rest] = undef
-lex ['+':rest] = undef
-lex ['-':rest] = undef
-lex ['*':rest] = undef
-lex ['/':rest] = undef
-lex ['%':rest] = undef
-lex ['=':rest] = undef
-lex ['<':rest] = undef
-lex ['>':rest] = undef
-lex ['!':rest] = undef
-lex ['\'':'\\':x:'\'':rest] = case x of
- 'a' = undef // (CharToken '\a')
- 'b' = undef // (CharToken '\b')
- 'f' = undef // (CharToken '\f')
- 'n' = undef // (CharToken '\n')
- 'r' = undef // (CharToken '\r')
- 't' = undef // (CharToken '\t')
- 'v' = undef // (CharToken '\v')
- _ = Left ("Illegal escape: \\" +++ toString x)
-lex ['\'':x:'\'':rest] = undef
-lex [x:xs]
-| isSpace x = lex xs
-| isDigit x = undef //Parse Int
-| isAlpha x = undef //Parse ident
-| otherwise = Left ("Unexpected character: " +++ toString x)
+lexer :: [Char] -> LexerOutput
+lexer x = lexer` x 1
+ where
+ lexer` :: [Char] Int -> LexerOutput
+ lexer` [] i = Right []
+ lexer` x i = case lex x i of
+ (Right t, rest, i) = lexer` rest i >>= \ts.Right [t:ts]
+ (Left e, _, _) = Left e
-:: LexerOutput :== Either String [Token]
+ret:: TokenValue [Char] Int -> (Either String Token, [Char], Int)
+ret tv rest i = (Right (i, tv), rest, i)
-Start = toString sp
- where
- sp :: LexerOutput
- sp = Right [
- WhileToken,
- BraceOpenToken,
- TrueToken,
- BraceCloseToken,
- CBraceOpenToken,
- VarToken,
- IdentToken ['x'],
- AssignmentToken,
- IdentToken ['x'],
- PlusToken,
- NumberToken 5,
- SColonToken,
- CBraceCloseToken]
+err :: String Int -> (Either String Token, [Char], Int)
+err s i = (Left ("Line " +++ toString i +++ ": " +++ s), [], i)
-//:: LexerOutput a :== Either String a
-//
-//
-//runParser :: (Parser a) [Char] -> (LexerOutput a, [Char])
-//runParser (Parser p) s = p s
-//
-//lexer :: [Char] -> LexerOutput [Token]
-//
-////lexer functions
-//identT = alpha >>= \a -> many (char '_' <|> alphaNum) >>= \as -> return $ IdentToken [a:as]
-//numberT = optional (char '-') >>= \sign -> (some digit) >>= \n -> case sign of
-// Nothing -> return $ NumberToken $ 5 //fromString n
-// _ -> return $ NumberToken $ -5 //(fromString n) * -1
-//charLT = CharToken <$> (char '\'' *> item <* char '\'')
-//char2T = item >>= \c1 -> case c1 of
-// ':' = char ':' >>| return DoubleColonToken
-// '<' = char '=' >>| return LesserEqToken
-// '>' = char '=' >>| return GreaterEqToken
-// '=' = char '=' >>| return EqualsToken
-// '&' = char '&' >>| return AmpersandsToken
-// '|' = char '|' >>| return PipesToken
-// '-' = char '>' >>| return ArrowToken
-// _ = zero
-//char1T = item >>= \c1 -> findT c1 charTokenMap
-//varT = string (fromString "var") >>| return VarToken
-//voidT = string (fromString "Void") >>| return VoidToken
-//returnT = string (fromString "return") >>| return ReturnToken
-//ifT = string (fromString "if") >>| return IfToken
-//elseT = string (fromString "else") >>| return ElseToken
-//whileT = string (fromString "while") >>| return WhileToken
-//trueT = string (fromString "True") >>| return TrueToken
-//falseT = string (fromString "False") >>| return FalseToken
-////note, for the anyToken parser the order matters!
-//anyT = char2T <|> char1T <|> varT <|> voidT <|> returnT <|> ifT <|> elseT <|> whileT <|>
-// trueT <|> falseT <|> numberT <|> identT <|> charLT
-//
-//Start :: *World -> *World
-//Start w
-//# (args, w) = getCommandLine w // We lezen nu nog standaard van stdin
-//# (out, w) = stdio w
-//# (toparse, out) = readEntireFile out
-//# out = out <<< toString (lexer toparse)
-//# (b, w) = fclose out w
-//| not b = setReturnCode 1 w
-//= w
-// where
-// readEntireFile :: *File -> *([Char], *File)
-// readEntireFile f
-// # (b, c, f) = freadc f
-// | not b = ([], f)
-// # (cs, f) = readEntireFile f
-// = ([c:cs], f)
-//
-//
-//
-//charTokenMap = [('(', BraceOpenToken)
-// ,(')', BraceCloseToken)
-// ,('{', CBraceOpenToken)
-// ,('}', CBraceCloseToken)
-// ,('[', SquareOpenToken)
-// ,(']', SquareCloseToken)
-// ,(',', CommaToken)
-// ,(':', ColonToken)
-// ,(';', SColonToken)
-// ,('.', DotToken)
-// ,('+', PlusToken)
-// ,('-', DashToken)
-// ,('*', StarToken)
-// ,('/', SlashToken)
-// ,('%', PercentToken)
-// ,('=', AssignmentToken)
-// ,('<', LesserToken)
-// ,('>', BiggerToken)
-// ,('!', ExclamationToken)]
-//findT c [] = fail "Unrecognized character"
-//findT c [(k,v):xs] = if (c==k) (return v) (findT c xs)
-//
-//
-//// Clean adaption of Yard, a parsec like parser combinator
-//:: Parser a = Parser ([Char] -> (LexerOutput a, [Char]))
-//
-//runParser :: (Parser a) [Char] -> (LexerOutput a, [Char])
-//runParser (Parser p) s = p s
-//
-//instance Functor Parser where
-// fmap f s = liftM f s
-//
-//instance Applicative Parser where
-// pure a = Parser $ \s -> (Right a, s)
-// (<*>) sf s = ap sf s
-//
-//instance Monad Parser where
-// bind p f = Parser $ \s -> let (out, rest) = runParser p s in case out of
-// Left e = (Left e, rest)
-// Right t = runParser (f t) rest
-//
-////gives us some, many and optional
-//instance Alternative Parser where
-// empty = zero
-// (<|>) p1 p2 = Parser $ \s -> let (out, rest) = runParser p1 s in case out of
-// Left e = runParser p2 s
-// Right t = (Right t, rest)
-//
-////parser that fails with error
-//fail :: String -> Parser a
-//fail e = Parser $ \s -> (Left e, s)
-//
-////parser that always fails
-//zero :: Parser a
-//zero = fail "Zero parser"
-//
-////matches exactly one Char
-//item :: Parser Char
-//item = Parser $ \s -> case s of
-// [] = (Left "Unexpected empty input", s)
-// [x:xs] = (Right x, xs)
-//
-////matches any char which satisfies f
-//satisfy :: (Char -> Bool) -> Parser Char
-//satisfy f = item >>= (\r -> if (f r) (return r) zero)
-//
-////tries a parser, if it fails returns a default value
-//optionalDef :: a (Parser a) -> Parser a
-//optionalDef def p = p <|> return def
-//
-////matched given char
-//char :: Char -> Parser Char
-//char c = satisfy (\i -> c==i) //I hate that we can't do: satisfy (==c)
-//
-//alpha :: Parser Char
-//alpha = satisfy isAlpha
-//
-//digit :: Parser Char
-//digit = satisfy isDigit
-//
-//alphaNum :: Parser Char
-//alphaNum = alpha <|> digit
-//
-////matches a given String
-//string :: [Char] -> Parser [Char]
-//string s = mapM_ char s >>| return s
+lex :: [Char] -> (Int -> (Either String Token, [Char], Int))
+lex [] = ret EndOfFileToken []
+lex ['/':'/':xs] = lex (dropWhile ((<>) '\n') xs)
+lex ['/':'*':xs] = \i.let (c, r) = span ((<>) ('*','/')) $ zip2 [' ':xs] xs in
+ lex (tl $ map snd $ tl $ r) (i + length [x\\(x, _)<-c | x == '\n'])
+lex ['v':'a':'r':xs] = ret VarToken xs
+lex ['V':'o':'i':'d':xs] = ret VoidToken xs
+lex ['r':'e':'t':'u':'r':'n':xs] = ret ReturnToken xs
+lex ['i':'f':xs] = ret IfToken xs
+lex ['e':'l':'s':'e':xs] = ret ElseToken xs
+lex ['w':'h':'i':'l':'e':xs] = ret WhileToken xs
+lex ['T':'r':'u':'e':xs] = ret TrueToken xs
+lex ['F':'a':'l':'s':'e':xs] = ret FalseToken xs
+lex ['I':'n':'t':xs] = ret IntTypeToken xs
+lex ['C':'h':'a':'r':xs] = ret CharTypeToken xs
+lex ['B':'o':'o':'l':xs] = ret BoolTypeToken xs
+lex [':':':':xs] = ret DoubleColonToken xs
+lex ['!':'=':xs] = ret NotEqualToken xs
+lex ['<':'=':xs] = ret LesserEqToken xs
+lex ['>':'=':xs] = ret GreaterEqToken xs
+lex ['=':'=':xs] = ret EqualsToken xs
+lex ['&':'&':xs] = ret AmpersandsToken xs
+lex ['|':'|':xs] = ret PipesToken xs
+lex ['-':'>':xs] = ret ArrowToken xs
+lex ['\'':x:'\'':xs] = ret (CharToken x) xs
+lex ['\'':'\\':x:'\'':xs] = case get x EscapeMap of
+ Just t = ret (CharToken t) xs
+ _ = err ("Unknown escape: \\" +++ toString x)
+lex ['-':t=:[x:xs]]
+| isDigit x = let (n, r) = span isDigit t in
+ ret (NumberToken (toInt $ toString ['-':n])) r
+| otherwise = ret DashToken xs
+lex t=:[x:xs] = case get x SingleCharTokens of
+ (Just tok) = ret tok xs
+ Nothing
+ | x == '\n' = \i.lex xs (i+1)
+ | isSpace x = lex xs
+ | isDigit x = let (v, r) = span isDigit t in
+ ret (NumberToken (toInt $ toString v)) r
+ | isAlpha x = let (v, r) = span isIdent t in ret (IdentToken v) r
+ with isIdent c = isAlphanum c || c == '_'
+ | otherwise = err ("Unexpected character: " +++ toString x)
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