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module Tokenizer (
tokenize,
) where
import qualified Data.Bifunctor as B
import Control.Monad.Except
import Utils
data TChar = TChar {
tChar :: Char,
tRow :: Int,
tColumn :: Int
}
posTChar :: String -> TChar -> String
posTChar fileName TChar { tRow = r, tColumn = c } = fileName ++ ":" ++ show r ++ ":" ++ show c
_tokenize :: String -> [Token] -> [TChar] -> [TChar] -> LContext [Token]
_tokenize fileName acc current [] =
let cur = reverse current
token = Token {
tokenContent = cur $> map tChar,
tokenRow = tRow $ head cur,
tokenColumn = tColumn $ head cur,
tokenFileName = fileName }
in return $ token : acc
_tokenize fileName acc current (x:xs)
| tChar x == ';' =
let commentDropped = dropWhile (\tc -> tChar tc /= '\n') xs
cur = reverse current
token = Token {
tokenContent = cur $> map tChar,
tokenRow = tRow $ head cur,
tokenColumn = tColumn $ head cur,
tokenFileName = fileName }
in _tokenize fileName (token : acc) [] commentDropped
| tChar x == '"' =
-- String length -1 signals an unbalanced error
let inc k n = if n == -1 then -1 else n + k
consume :: String -> (String, Int)
consume str = case str of
('\\':'"':rest) -> B.bimap ('\"' :) (inc 2) (consume rest)
('\\':'n':rest) -> B.bimap ('\n' :) (inc 2) (consume rest)
('\\':'t':rest) -> B.bimap ('\t' :) (inc 2) (consume rest)
('"':_) -> ("", 1)
(c:rest) -> B.bimap (c :) (inc 1) (consume rest)
[] -> ("", -1)
(string, stringLength) = consume (map tChar xs)
stringDropped = drop (stringLength) xs
withQuotes = "\"" ++ string ++ "\""
token = Token {
tokenContent = withQuotes,
tokenRow = tRow $ x,
tokenColumn = tColumn $ x,
tokenFileName = fileName }
in do
when (stringLength == -1) $ throwL (posTChar fileName x) $ "unbalanced string literal"
_tokenize fileName (token : acc) [] stringDropped
| tChar x `elem` [' ', '\n', '\t', '\r'] =
let cur = reverse current
token = Token {
tokenContent = cur $> map tChar,
tokenRow = tRow $ head cur,
tokenColumn = tColumn $ head cur,
tokenFileName = fileName }
in _tokenize fileName (token : acc) [] xs
| tChar x `elem` ['(', ')', '[', ']', '{', '}', '\\'] =
let cur = reverse current
token1 = Token {
tokenContent = [tChar x],
tokenRow = tRow x,
tokenColumn = tColumn x,
tokenFileName = fileName
}
token2 = Token {
tokenContent = cur $> map tChar,
tokenRow = tRow $ head cur,
tokenColumn = tColumn $ head cur,
tokenFileName = fileName
}
in _tokenize fileName (token1 : token2 : acc) [] xs
| otherwise = _tokenize fileName acc (x : current) xs
tokenize :: String -> String -> LContext [Token]
tokenize fileName src = do
let tChars = augment 0 0 src
tokens <- _tokenize fileName [] [] tChars
return $ tokens
$> reverse
.> filter (\t -> length (tokenContent t) > 0)
where
augment row col ('\r':'\n':rest) =
TChar '\n' row col : augment 0 (col + 1) rest
augment row col ('\n':rest) =
TChar '\n' row col : augment 0 (col + 1) rest
augment row col (c:rest) =
TChar c (row + 1) col : augment 0 (col + 1) rest
augment _ _ [] = []
|
