implementation module lex
-import Control.Monad
+import Control.Monad, Control.Applicative
import Data.Either, Data.Maybe, Data.Map, Data.Func
import StdString
import StdTuple
+from StdFunc import const, o
import StdBool
import StdList
import StdChar
-SingleCharTokens :: Map Char TokenValue
-SingleCharTokens = fromList [
- ('(', BraceOpenToken), (')', BraceCloseToken), ('{', CBraceOpenToken),
- ('}', CBraceCloseToken), ('[', SquareOpenToken), (']', SquareCloseToken),
- (',', CommaToken), (':', ColonToken), (';', SColonToken),
- ('.', DotToken), ('+', PlusToken), ('*', StarToken), ('/', SlashToken),
- ('%', PercentToken), ('=', AssignmentToken), ('<', LesserToken),
- ('>', BiggerToken), ('!', ExclamationToken), ('-', DashToken)]
-
-EscapeMap :: Map Char Char
-EscapeMap = fromList [('a', toChar 7), ('b', '\b'), ('f', '\f'), ('n', '\n'),
- ('r', '\r'), ('t', '\t'), ('v', '\v')]
+import yard
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
+lexer r = case runParser lexProgram r of
+ (Right p, _) = Right p
+ (Left e, _) = Left $ toString e
+
+trans1 :: Char a -> Parser Char a
+trans1 t r = item t >>| pure r
+
+lexProgram :: Parser Char [Token]
+lexProgram = lexToken >>= \t->pure [(0, 0, t)]
+
+lexToken :: Parser Char TokenValue
+lexToken =
+ (lexKw "var" VarToken) <|>
+ (lexKw "Void" VoidToken) <|>
+ (lexKw "return" ReturnToken) <|>
+ (lexKw "if" IfToken) <|>
+ (lexKw "else" ElseToken) <|>
+ (lexKw "while" WhileToken) <|>
+ (lexKw "True" TrueToken) <|>
+ (lexKw "False" FalseToken) <|>
+ (lexKw "Int" IntTypeToken) <|>
+ (lexKw "Bool" BoolTypeToken) <|>
+ (lexKw "Char" CharTypeToken) <|>
+ //Escape chars
+ (liftM CharToken $ item '\'' *> item '\\' *> lexEscape <* item '\'') <|>
+ //Normal chars
+ (liftM CharToken $ item '\'' *> satisfy ((<>) '\'') <* item '\'') <|>
+ (lexOp "::" DoubleColonToken) <|>
+ (lexOp "!=" NotEqualToken) <|>
+ (lexOp "<=" LesserEqToken) <|>
+ (lexOp ">=" GreaterEqToken) <|>
+ (lexOp "==" EqualsToken) <|>
+ (lexOp "&&" AmpersandsToken) <|>
+ (lexOp "||" PipesToken) <|>
+ (lexOp "[]" EmptyListToken) <|>
+ (lexOp "->" ArrowToken) <|>
+ (lexOp "(" BraceOpenToken) <|>
+ (lexOp ")" BraceCloseToken) <|>
+ (lexOp "{" CBraceOpenToken) <|>
+ (lexOp "}" CBraceCloseToken) <|>
+ (lexOp "[" SquareOpenToken) <|>
+ (lexOp "]" SquareCloseToken) <|>
+ (lexOp "," CommaToken) <|>
+ (lexOp ":" ColonToken) <|>
+ (lexOp ";" SColonToken) <|>
+ (lexOp "." DotToken) <|>
+ (lexOp "+" PlusToken) <|>
+ (lexOp "*" StarToken) <|>
+ (lexOp "/" SlashToken) <|>
+ (lexOp "%" PercentToken) <|>
+ (lexOp "=" AssignmentToken) <|>
+ (lexOp "<" LesserToken) <|>
+ (lexOp ">" BiggerToken) <|>
+ (lexOp "!" ExclamationToken) <|>
+ (lexOp "-" DashToken) <|>
+ //Numbers
+ (liftM (NumberToken o toInt o toString) $ some $ satisfy isDigit) <|>
+ //Identifiersr
+ (liftM IdentToken $ some $ satisfy isIdentChar) <|>
+ (satisfy isSpace >>| lexToken)
+
+lexEscape = (
+ lexOp "a" (toChar 7) <|>
+ lexOp "b" '\b' <|>
+ lexOp "f" '\f' <|>
+ lexOp "n" '\n' <|>
+ lexOp "r" '\t' <|>
+ lexOp "v" '\v' <|>
+ lexOp "'" '\''
+ ) <?> ("Unknown escape", 0)
-ret:: TokenValue [Char] Int -> (Either String Token, [Char], Int)
-ret tv rest i = (Right (i, tv), rest, i)
+lexKw :: String a -> Parser Char a
+lexKw kw tv = list (fromString kw) <* check (not o isIdentChar) >>| pure tv
-err :: String Int -> (Either String Token, [Char], Int)
-err s i = (Left ("Line " +++ toString i +++ ": " +++ s), [], i)
+lexOp :: String a -> Parser Char a
+lexOp s tv = list (fromString s) >>| pure tv
-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 EmptyListToken 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] = 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)
+isIdentChar :: Char -> Bool
+isIdentChar c = isAlphanum c || c == '_'
repositories / cc1516.git / commitdiff