werkt

[cc1516.git] / lex.icl

diff --git a/lex.icl b/lex.icl
index f050062..de200df 100644 (file)
--- a/lex.icl
+++ b/lex.icl
@@ -1,3 +1,80 @@
-module lex
+implementation module lex
 
-Start = "Hello World!\n"
+import Control.Monad
+import Data.Either, Data.Maybe, Data.Map, Data.Func
+import StdString
+import StdTuple
+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)]
+
+EscapeMap :: Map Char Char
+EscapeMap = fromList [('a', toChar 7), ('b', '\b'), ('f', '\f'), ('n', '\n'),
+       ('r', '\r'), ('t', '\t'), ('v', '\v')]
+
+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
+
+ret:: TokenValue [Char] Int -> (Either String Token, [Char], Int)
+ret tv rest i = (Right (i, tv), rest, i)
+
+err :: String Int -> (Either String Token, [Char], Int)
+err s i = (Left ("Line " +++ toString i +++ ": " +++ s), [], i)
+
+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)