negative numbers are lexed

diff --git a/lex.icl b/lex.icl
index 876e302..0adb20c 100644 (file)
--- a/lex.icl
+++ b/lex.icl
@@ -17,9 +17,9 @@ SingleCharTokens = fromList [
        ('(', BraceOpenToken), (')', BraceCloseToken), ('{', CBraceOpenToken),
        ('}', CBraceCloseToken), ('[', SquareOpenToken), (']', SquareCloseToken),
        (',', CommaToken), (':', ColonToken), (';', SColonToken),
-       ('.', DotToken), ('+', PlusToken), ('-', DashToken), ('*', StarToken),
-       ('/', SlashToken), ('%', PercentToken), ('=', AssignmentToken),
-       ('<', LesserToken), ('>', BiggerToken), ('!', ExclamationToken)]
+       ('.', DotToken), ('+', PlusToken), ('*', StarToken), ('/', SlashToken),
+       ('%', PercentToken), ('=', AssignmentToken), ('<', LesserToken),
+       ('>', BiggerToken), ('!', ExclamationToken)]
 
 EscapeMap :: Map Char Char
 EscapeMap = fromList [('a', toChar 7), ('b', '\b'), ('f', '\f'), ('n', '\n'),
@@ -34,7 +34,8 @@ lexer x = case lex x of
 lex :: [Char] -> (Either String Token, [Char])
 lex [] = (Right EndOfFileToken, [])
 lex ['/':'/':xs] = lex $ dropWhile ((<>) '\n') xs
-lex ['/':'*':xs] = lex $ tl $ map snd $ dropWhile ((<>) ('*', '/')) $ zip2 [zero:xs] xs
+lex ['/':'*':xs] =
+       lex $ tl $ map snd $ dropWhile ((<>) ('*', '/')) $ zip2 [zero:xs] xs
 lex ['v':'a':'r':xs] = (Right VarToken, xs)
 lex ['V':'o':'i':'d':xs] = (Right VoidToken, xs)
 lex ['r':'e':'t':'u':'r':'n':xs] = (Right ReturnToken, xs)
@@ -58,12 +59,14 @@ lex ['\'':x:'\'':xs] = (Right (CharToken x), xs)
 lex ['\'':'\\':x:'\'':xs] = case get x EscapeMap of
        Just t = (Right (CharToken t), xs)
        _ = (Left ("Unknown escape: \\" +++ toString x), [])
-lex [x:xs]
-# t = get x SingleCharTokens
-| isJust t = (Right (fromJust t), xs)
-| isSpace x = lex xs
-| isDigit x = let (is, xs`) = span isDigit xs in
-       (Right (NumberToken [x:is]), xs`)
-| isAlpha x = let (is, xs`) = span (\c.isAlphanum c || c == '_') xs in
-       (Right (IdentToken [x:is]), xs`)
-| otherwise = (Left ("Unexpected character: " +++ toString x), [])
+lex ['-':t=:[x:xs]]
+| isDigit x = let (i, r) = span isDigit t in (Right (NumberToken ['-':i]), r)
+| otherwise = (Right DashToken, xs)
+lex t=:[x:xs] = case get x SingleCharTokens of
+       (Just tok) = (Right tok, xs)
+       Nothing
+       | isSpace x = lex xs
+       | isDigit x = let (i, r) = span isDigit t in (Right (NumberToken i), r)
+       | isAlpha x = let (i, r) = span isIdent t in (Right (IdentToken i), r)
+               with isIdent c = isAlphanum c || c == '_'
+       | otherwise = (Left ("Unexpected character: " +++ toString x), [])