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module CommonParsing where
import Data.Char
import Data.Functor
import Text.Parsec
import Text.Parsec.Char
import Text.Parsec.Combinator
type Parser a b = Parsec String a b
kw :: String -> Parser a ()
kw s = try $ string s <* spaces $> ()
kwIf :: Parser a ()
kwIf = kw "if"
kwThen :: Parser a ()
kwThen = kw "then"
kwElse :: Parser a ()
kwElse = kw "else"
kwElsif :: Parser a ()
kwElsif = kw "elsif"
kwWhile :: Parser a ()
kwWhile = kw "while"
kwState :: Parser a ()
kwState = kw "state"
kwEffect :: Parser a ()
kwEffect = kw "effect"
kwCombine :: Parser a ()
kwCombine = kw "combine"
kwRand :: Parser a ()
kwRand = kw "rand"
kwFunction :: Parser a ()
kwFunction = kw "function"
kwSorted :: Parser a ()
kwSorted = kw "sorted"
kwLet :: Parser a ()
kwLet = kw "let"
kwTraverser :: Parser a ()
kwTraverser = kw "traverser"
kwReturn :: Parser a ()
kwReturn = kw "return"
op :: String -> op -> Parser a op
op s o = string s $> o
int :: Parser a Int
int = read <$> (many1 digit <* spaces)
var :: [String] -> Parser a String
var reserved =
do
c <- satisfy $ \c -> isLetter c || c == '_'
cs <- many (satisfy isLetter <|> digit) <* spaces
let name = c:cs
if name `elem` reserved
then fail "Can't use reserved keyword as identifier"
else return name
list :: Char -> Char -> Char -> Parser a b -> Parser a [b]
list co cc cd pe = surround co cc $ sepBy pe (char cd >> spaces)
surround :: Char -> Char -> Parser a b -> Parser a b
surround c1 c2 pe =
do
char c1 >> spaces
e <- pe
spaces >> char c2 >> spaces
return e
level :: (o -> e -> e -> e) -> Parser a o -> Parser a e -> Parser a e
level c po pe =
do
e <- pe <* spaces
ops <- many $ try $ (flip . c <$> (po <* spaces) <*> pe) <* spaces
return $ foldl (flip ($)) e ops
precedence :: (o -> e -> e -> e) -> Parser a e -> [ Parser a o ] -> Parser a e
precedence = foldl . flip . level