implementation module lex
+import Control.Monad
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 Data.Map
+import StdString
+import StdBool
+import StdList
+import StdChar
import qualified Text
-lexer :: [Char] -> LexerOutput
-lexer _ = undef
+SingleCharTokens :: Map Char Token
+SingleCharTokens = fromList [
+ ('(', BraceOpenToken), (')', BraceCloseToken), ('{', CBraceOpenToken),
+ ('}', CBraceCloseToken), ('[', SquareOpenToken), (']', SquareCloseToken),
+ (',', CommaToken), (':', ColonToken), (';', SColonToken),
+ ('.', DotToken), ('+', PlusToken), ('-', DashToken), ('*', StarToken),
+ ('/', SlashToken), ('%', PercentToken), ('=', AssignmentToken),
+ ('<', LesserToken), ('>', BiggerToken), ('!', ExclamationToken)]
-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]
+EscapeMap :: Map Char Char
+EscapeMap = fromList [
+ ('a', toChar 7), ('b', '\b'), ('f', '\f'), ('n', '\n'), ('r', '\r'),
+ ('t', '\t'), ('v', '\v')]
-tab :: Int -> String
-tab 0 = ""
-tab i = "\t" +++ tab (i-1)
-
-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)
-
-:: LexerOutput :== Either String [Token]
-
-Start = toString sp
- where
- sp :: LexerOutput
- sp = Right [
- WhileToken,
- BraceOpenToken,
- TrueToken,
- BraceCloseToken,
- CBraceOpenToken,
- VarToken,
- IdentToken ['x'],
- AssignmentToken,
- IdentToken ['x'],
- PlusToken,
- NumberToken 5,
- SColonToken,
- CBraceCloseToken]
+lexer :: [Char] -> LexerOutput
+lexer [] = Right []
+lexer x = case lex x of
+ (Right t, rest) = lexer rest >>= \ts.Right [t:ts]
+ (Left e, _) = Left e
-//:: 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] -> (Either String Token, [Char])
+lex [] = (Right EndOfFileToken, [])
+lex ['/':'/':x:rest] = if (x == '\n') (lex rest) (lex ['/':'/':rest])
+lex ['/':'*':x1:x2:rest] = if (x1 == '*' && x2 == '/')
+ (lex rest) (lex ['/':'*':rest])
+lex ['v':'a':'r':rest] = (Right VarToken, rest)
+lex ['V':'o':'i':'d':rest] = (Right VoidToken, rest)
+lex ['r':'e':'t':'u':'r':'n':rest] = (Right ReturnToken, rest)
+lex ['i':'f':rest] = (Right IfToken, rest)
+lex ['e':'l':'s':'e':rest] = (Right ElseToken, rest)
+lex ['w':'h':'i':'l':'e':rest] = (Right WhileToken, rest)
+lex ['T':'r':'u':'e':rest] = (Right TrueToken, rest)
+lex ['F':'a':'l':'s':'e':rest] = (Right FalseToken, rest)
+lex ['I':'n':'t':rest] = (Right IntTypeToken, rest)
+lex ['C':'h':'a':'r':rest] = (Right CharTypeToken, rest)
+lex ['B':'o':'o':'l':rest] = (Right BoolTypeToken, rest)
+lex [':':':':rest] = (Right DoubleColonToken, rest)
+lex ['!':'=':rest] = (Right NotEqualToken, rest)
+lex ['<':'=':rest] = (Right LesserEqToken, rest)
+lex ['>':'=':rest] = (Right GreaterEqToken, rest)
+lex ['=':'=':rest] = (Right EqualsToken, rest)
+lex ['&':'&':rest] = (Right AmpersandsToken, rest)
+lex ['|':'|':rest] = (Right PipesToken, rest)
+lex ['-':'>':rest] = (Right ArrowToken, rest)
+lex ['\'':x:'\'':rest] = (Right (CharToken x), rest)
+lex ['\'':'\\':x:'\'':rest] = case get x EscapeMap of
+ Just t = (Right (CharToken t), rest)
+ _ = (Left ("Unknown escape: \\" +++ toString x), [])
+lex [x:rest]
+# t = get x SingleCharTokens
+| isJust t = (Right (fromJust t), rest)
+| isSpace x = lex rest
+| isDigit x = let (is, rest`) = span isDigit rest in
+ (Right (NumberToken [x:is]), rest`)
+| isAlpha x = let (is, rest`) = span (\c.isAlphanum c || c == '_') rest in
+ (Right (IdentToken [x:is]), rest`)
+| otherwise = (Left ("Unexpected character: " +++ toString x), [])
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