module Bookhound.Parser (Parser, ParseResult, ParseError(..), runParser, errorParser,
               andThen, exactly, isMatch, check, except, anyOf, allOf, char,
               withTransform, withError) where

import Control.Applicative (liftA2)
import Control.Monad       (join)
import Data.Either         (fromRight)
import Data.List           (find)
import Data.Maybe          (isJust)
import Data.Text           (Text, pack, uncons, unpack)

type Input = Text

data Parser a
  = P
      { forall a. Parser a -> Input -> ParseResult a
parse     :: Input -> ParseResult a
      , forall a. Parser a -> forall b. Maybe (Parser b -> Parser b)
transform :: forall b. Maybe (Parser b -> Parser b)
      }

data ParseResult a
  = Result Input a
  | Error ParseError
  deriving (ParseResult a -> ParseResult a -> Bool
forall a. Eq a => ParseResult a -> ParseResult a -> Bool
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: ParseResult a -> ParseResult a -> Bool
$c/= :: forall a. Eq a => ParseResult a -> ParseResult a -> Bool
== :: ParseResult a -> ParseResult a -> Bool
$c== :: forall a. Eq a => ParseResult a -> ParseResult a -> Bool
Eq)

data ParseError
  = UnexpectedEof
  | ExpectedEof Input
  | UnexpectedChar Char
  | UnexpectedString String
  | NoMatch String
  deriving (ParseError -> ParseError -> Bool
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: ParseError -> ParseError -> Bool
$c/= :: ParseError -> ParseError -> Bool
== :: ParseError -> ParseError -> Bool
$c== :: ParseError -> ParseError -> Bool
Eq, Int -> ParseError -> ShowS
[ParseError] -> ShowS
ParseError -> String
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
showList :: [ParseError] -> ShowS
$cshowList :: [ParseError] -> ShowS
show :: ParseError -> String
$cshow :: ParseError -> String
showsPrec :: Int -> ParseError -> ShowS
$cshowsPrec :: Int -> ParseError -> ShowS
Show)


instance Show a => Show (ParseResult a) where
  show :: ParseResult a -> String
show (Result Input
i a
a)                 = String
"Pending: " forall a. Semigroup a => a -> a -> a
<> String
" >" forall a. Semigroup a => a -> a -> a
<> Input -> String
unpack Input
i forall a. Semigroup a => a -> a -> a
<> String
"< " forall a. Semigroup a => a -> a -> a
<>
                                      String
"\n\nResult: \n" forall a. Semigroup a => a -> a -> a
<> forall a. Show a => a -> String
show a
a
  show (Error ParseError
UnexpectedEof)        = String
"Unexpected end of stream"
  show (Error (ExpectedEof Input
i))      = String
"Expected end of stream, but got >"
                                       forall a. Semigroup a => a -> a -> a
<> Input -> String
unpack Input
i forall a. Semigroup a => a -> a -> a
<> String
"<"
  show (Error (UnexpectedChar Char
c))   = String
"Unexpected char: "   forall a. Semigroup a => a -> a -> a
<> String
"[" forall a. Semigroup a => a -> a -> a
<> forall a. Show a => a -> String
show Char
c forall a. Semigroup a => a -> a -> a
<> String
"]"
  show (Error (UnexpectedString String
s)) = String
"Unexpected string: " forall a. Semigroup a => a -> a -> a
<> String
"[" forall a. Semigroup a => a -> a -> a
<> forall a. Show a => a -> String
show String
s forall a. Semigroup a => a -> a -> a
<> String
"]"
  show (Error (NoMatch String
s))          = String
"Did not match condition: " forall a. Semigroup a => a -> a -> a
<> String
s


instance Functor ParseResult where
  fmap :: forall a b. (a -> b) -> ParseResult a -> ParseResult b
fmap a -> b
f (Result Input
i a
a) = forall a. Input -> a -> ParseResult a
Result Input
i (a -> b
f a
a)
  fmap a -> b
_ (Error ParseError
pe)   = forall a. ParseError -> ParseResult a
Error ParseError
pe


instance Functor Parser where
  fmap :: forall a b. (a -> b) -> Parser a -> Parser b
fmap a -> b
f (P Input -> ParseResult a
p forall b. Maybe (Parser b -> Parser b)
t) = forall b.
(forall b. Maybe (Parser b -> Parser b)) -> Parser b -> Parser b
applyTransform forall b. Maybe (Parser b -> Parser b)
t forall a b. (a -> b) -> a -> b
$ forall a. (Input -> ParseResult a) -> Parser a
mkParser (forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap a -> b
f forall b c a. (b -> c) -> (a -> b) -> a -> c
. Input -> ParseResult a
p)

instance Applicative Parser where
  pure :: forall a. a -> Parser a
pure a
a      = forall a. (Input -> ParseResult a) -> Parser a
mkParser (forall a. Input -> a -> ParseResult a
`Result` a
a)
  (liftA2 :: forall a b c. (a -> b -> c) -> Parser a -> Parser b -> Parser c
liftA2) a -> b -> c
f (P Input -> ParseResult a
p forall b. Maybe (Parser b -> Parser b)
t) mb :: Parser b
mb@(P Input -> ParseResult b
_ forall b. Maybe (Parser b -> Parser b)
t') =
    forall b.
(forall b. Maybe (Parser b -> Parser b)) -> Parser b -> Parser b
applyTransform (forall a. Maybe a -> Maybe a -> Maybe a
findJust forall b. Maybe (Parser b -> Parser b)
t forall b. Maybe (Parser b -> Parser b)
t') Parser c
combinedParser
    where
      combinedParser :: Parser c
combinedParser = forall a. (Input -> ParseResult a) -> Parser a
mkParser (
        \Input
x -> case Input -> ParseResult a
p Input
x of
        Result Input
i a
a -> forall a. Parser a -> Input -> ParseResult a
parse ((a -> b -> c
f a
a) forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> Parser b
mb) Input
i
        Error ParseError
pe   -> forall a. ParseError -> ParseResult a
Error ParseError
pe)

instance Monad Parser where
  >>= :: forall a b. Parser a -> (a -> Parser b) -> Parser b
(>>=) (P Input -> ParseResult a
p forall b. Maybe (Parser b -> Parser b)
t) a -> Parser b
f = forall b.
(forall b. Maybe (Parser b -> Parser b)) -> Parser b -> Parser b
applyTransform forall b. Maybe (Parser b -> Parser b)
t Parser b
combinedParser
    where
      combinedParser :: Parser b
combinedParser = forall a. (Input -> ParseResult a) -> Parser a
mkParser (
        \Input
x -> case  Input -> ParseResult a
p Input
x of
        Result Input
i a
a -> forall a. Parser a -> Input -> ParseResult a
parse (a -> Parser b
f a
a) Input
i
        Error ParseError
pe   -> forall a. ParseError -> ParseResult a
Error ParseError
pe)

runParser :: Parser a -> Input -> Either ParseError a
runParser :: forall a. Parser a -> Input -> Either ParseError a
runParser Parser a
p Input
i = forall {b}. ParseResult b -> Either ParseError b
toEither forall a b. (a -> b) -> a -> b
$ forall a. Parser a -> Input -> ParseResult a
parse (forall a. Parser a -> Parser a
exactly Parser a
p) Input
i where

  toEither :: ParseResult b -> Either ParseError b
toEither = \case
    Error ParseError
pe   -> forall a b. a -> Either a b
Left ParseError
pe
    Result Input
_ b
a -> forall a b. b -> Either a b
Right b
a

errorParser :: ParseError -> Parser a
errorParser :: forall a. ParseError -> Parser a
errorParser = forall a. (Input -> ParseResult a) -> Parser a
mkParser forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall a b. a -> b -> a
const forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall a. ParseError -> ParseResult a
Error


char :: Parser Char
char :: Parser Char
char = forall a. (Input -> ParseResult a) -> Parser a
mkParser forall a b. (a -> b) -> a -> b
$
   forall b a. b -> (a -> b) -> Maybe a -> b
maybe (forall a. ParseError -> ParseResult a
Error ParseError
UnexpectedEof) (\(Char
ch, Input
rest) -> forall a. Input -> a -> ParseResult a
Result Input
rest Char
ch) forall b c a. (b -> c) -> (a -> b) -> a -> c
. Input -> Maybe (Char, Input)
uncons


andThen :: Parser String -> Parser a -> Parser a
andThen :: forall a. Parser String -> Parser a -> Parser a
andThen Parser String
p1 p2 :: Parser a
p2@(P Input -> ParseResult a
_ forall b. Maybe (Parser b -> Parser b)
t) = forall b.
(forall b. Maybe (Parser b -> Parser b)) -> Parser b -> Parser b
applyTransform forall b. Maybe (Parser b -> Parser b)
t forall a b. (a -> b) -> a -> b
$
  forall a.
(Input -> ParseResult a)
-> (forall b. Maybe (Parser b -> Parser b)) -> Parser a
P (\Input
i -> forall a. Parser a -> Input -> ParseResult a
parse Parser a
p2 forall a b. (a -> b) -> a -> b
$ forall b a. b -> Either a b -> b
fromRight Input
i forall a b. (a -> b) -> a -> b
$ String -> Input
pack forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> forall a. Parser a -> Input -> Either ParseError a
runParser Parser String
p1 Input
i) forall b. Maybe (Parser b -> Parser b)
t


exactly :: Parser a -> Parser a
exactly :: forall a. Parser a -> Parser a
exactly (P Input -> ParseResult a
p forall b. Maybe (Parser b -> Parser b)
t) = forall b.
(forall b. Maybe (Parser b -> Parser b)) -> Parser b -> Parser b
applyTransform forall b. Maybe (Parser b -> Parser b)
t forall a b. (a -> b) -> a -> b
$ forall a. (Input -> ParseResult a) -> Parser a
mkParser (
  \Input
x -> case Input -> ParseResult a
p Input
x of
    result :: ParseResult a
result@(Result Input
i a
_) | Input
i forall a. Eq a => a -> a -> Bool
== forall a. Monoid a => a
mempty -> ParseResult a
result
    Result Input
i a
_                        -> forall a. ParseError -> ParseResult a
Error forall a b. (a -> b) -> a -> b
$ Input -> ParseError
ExpectedEof Input
i
    err :: ParseResult a
err@(Error ParseError
_)                     -> ParseResult a
err)

anyOf :: [Parser a] -> Parser a
anyOf :: forall a. [Parser a] -> Parser a
anyOf [Parser a]
ps = forall a.
[Parser a] -> (forall b. Maybe (Parser b -> Parser b)) -> Parser a
anyOfHelper [Parser a]
ps forall a. Maybe a
Nothing

allOf :: [Parser a] -> Parser a
allOf :: forall a. [Parser a] -> Parser a
allOf [Parser a]
ps = forall a.
[Parser a] -> (forall b. Maybe (Parser b -> Parser b)) -> Parser a
allOfHelper [Parser a]
ps forall a. Maybe a
Nothing


anyOfHelper :: [Parser a] -> (forall b. Maybe (Parser b -> Parser b)) -> Parser a
anyOfHelper :: forall a.
[Parser a] -> (forall b. Maybe (Parser b -> Parser b)) -> Parser a
anyOfHelper [] forall b. Maybe (Parser b -> Parser b)
_  = forall a. ParseError -> Parser a
errorParser forall a b. (a -> b) -> a -> b
$ String -> ParseError
NoMatch String
"anyOf"
anyOfHelper [Parser a
p] forall b. Maybe (Parser b -> Parser b)
_ = Parser a
p
anyOfHelper ((P Input -> ParseResult a
p forall b. Maybe (Parser b -> Parser b)
t) : [Parser a]
rest) forall b. Maybe (Parser b -> Parser b)
t' = forall b.
(forall b. Maybe (Parser b -> Parser b)) -> Parser b -> Parser b
applyTransform (forall a. Maybe a -> Maybe a -> Maybe a
findJust forall b. Maybe (Parser b -> Parser b)
t forall b. Maybe (Parser b -> Parser b)
t') forall a b. (a -> b) -> a -> b
$
  forall a. (Input -> ParseResult a) -> Parser a
mkParser (
   \Input
x -> case Input -> ParseResult a
p Input
x of
    result :: ParseResult a
result@(Result Input
_ a
_) -> ParseResult a
result
    Error ParseError
_             -> forall a. Parser a -> Input -> ParseResult a
parse (forall a.
[Parser a] -> (forall b. Maybe (Parser b -> Parser b)) -> Parser a
anyOfHelper [Parser a]
rest forall b. Maybe (Parser b -> Parser b)
t) Input
x)



allOfHelper :: [Parser a] -> (forall b. Maybe (Parser b -> Parser b)) -> Parser a
allOfHelper :: forall a.
[Parser a] -> (forall b. Maybe (Parser b -> Parser b)) -> Parser a
allOfHelper [] forall b. Maybe (Parser b -> Parser b)
_ = forall a. ParseError -> Parser a
errorParser forall a b. (a -> b) -> a -> b
$ String -> ParseError
NoMatch String
"allOf"
allOfHelper [Parser a
p] forall b. Maybe (Parser b -> Parser b)
_ = Parser a
p
allOfHelper ((P Input -> ParseResult a
p forall b. Maybe (Parser b -> Parser b)
t) : [Parser a]
rest) forall b. Maybe (Parser b -> Parser b)
t' = forall b.
(forall b. Maybe (Parser b -> Parser b)) -> Parser b -> Parser b
applyTransform (forall a. Maybe a -> Maybe a -> Maybe a
findJust forall b. Maybe (Parser b -> Parser b)
t forall b. Maybe (Parser b -> Parser b)
t') forall a b. (a -> b) -> a -> b
$
  forall a. (Input -> ParseResult a) -> Parser a
mkParser (
   \Input
x -> case Input -> ParseResult a
p Input
x of
    Result Input
_ a
_    -> forall a. Parser a -> Input -> ParseResult a
parse (forall a.
[Parser a] -> (forall b. Maybe (Parser b -> Parser b)) -> Parser a
allOfHelper [Parser a]
rest forall b. Maybe (Parser b -> Parser b)
t) Input
x
    err :: ParseResult a
err@(Error ParseError
_) -> ParseResult a
err)



isMatch :: (Char -> Char -> Bool) -> Parser Char -> Char -> Parser Char
isMatch :: (Char -> Char -> Bool) -> Parser Char -> Char -> Parser Char
isMatch Char -> Char -> Bool
cond Parser Char
parser Char
c1 =
  do Char
c2 <- Parser Char
parser
     if Char -> Char -> Bool
cond Char
c1 Char
c2
       then forall (f :: * -> *) a. Applicative f => a -> f a
pure Char
c2
       else forall a. ParseError -> Parser a
errorParser forall a b. (a -> b) -> a -> b
$ Char -> ParseError
UnexpectedChar Char
c2

check :: String -> (a -> Bool) -> Parser a -> Parser a
check :: forall a. String -> (a -> Bool) -> Parser a -> Parser a
check String
condName a -> Bool
cond Parser a
parser =
  do a
c2 <- Parser a
parser
     if a -> Bool
cond a
c2
       then forall (f :: * -> *) a. Applicative f => a -> f a
pure a
c2
       else  forall a. ParseError -> Parser a
errorParser forall a b. (a -> b) -> a -> b
$ String -> ParseError
NoMatch String
condName


except :: Show a => Parser a -> Parser a -> Parser a
except :: forall a. Show a => Parser a -> Parser a -> Parser a
except (P Input -> ParseResult a
p forall b. Maybe (Parser b -> Parser b)
t) (P Input -> ParseResult a
p' forall b. Maybe (Parser b -> Parser b)
_) = forall b.
(forall b. Maybe (Parser b -> Parser b)) -> Parser b -> Parser b
applyTransform forall b. Maybe (Parser b -> Parser b)
t forall a b. (a -> b) -> a -> b
$ forall a. (Input -> ParseResult a) -> Parser a
mkParser (
  \Input
x -> case Input -> ParseResult a
p' Input
x of
    Result Input
_ a
a -> forall a. ParseError -> ParseResult a
Error forall a b. (a -> b) -> a -> b
$ String -> ParseError
UnexpectedString (forall a. Show a => a -> String
show a
a)
    Error ParseError
_    -> Input -> ParseResult a
p Input
x)

withError :: String -> Parser a -> Parser a
withError :: forall a. String -> Parser a -> Parser a
withError String
str parser :: Parser a
parser@(P Input -> ParseResult a
p forall b. Maybe (Parser b -> Parser b)
_) = Parser a
parser { $sel:parse:P :: Input -> ParseResult a
parse =
  \Input
i -> case Input -> ParseResult a
p Input
i of
    r :: ParseResult a
r@(Result Input
_ a
_) -> ParseResult a
r
    Error ParseError
_        -> forall a. ParseError -> ParseResult a
Error forall a b. (a -> b) -> a -> b
$ String -> ParseError
NoMatch String
str
  }

withTransform :: (forall b. Parser b -> Parser b) -> Parser a -> Parser a
withTransform :: forall a. (forall a. Parser a -> Parser a) -> Parser a -> Parser a
withTransform forall a. Parser a -> Parser a
f = forall b.
(forall b. Maybe (Parser b -> Parser b)) -> Parser b -> Parser b
applyTransform forall a b. (a -> b) -> a -> b
$ forall a. a -> Maybe a
Just forall a. Parser a -> Parser a
f


applyTransform :: (forall a. Maybe (Parser a -> Parser a)) -> Parser b -> Parser b
applyTransform :: forall b.
(forall b. Maybe (Parser b -> Parser b)) -> Parser b -> Parser b
applyTransform forall b. Maybe (Parser b -> Parser b)
f Parser b
p =  forall b a. b -> (a -> b) -> Maybe a -> b
maybe Parser b
p (\Parser b -> Parser b
f' -> (Parser b -> Parser b
f' Parser b
p){$sel:transform:P :: forall b. Maybe (Parser b -> Parser b)
transform = forall b. Maybe (Parser b -> Parser b)
f} ) forall b. Maybe (Parser b -> Parser b)
f

mkParser :: (Input -> ParseResult a) -> Parser a
mkParser :: forall a. (Input -> ParseResult a) -> Parser a
mkParser Input -> ParseResult a
p = P {$sel:parse:P :: Input -> ParseResult a
parse = Input -> ParseResult a
p, $sel:transform:P :: forall b. Maybe (Parser b -> Parser b)
transform = forall a. Maybe a
Nothing}

findJust :: forall a. Maybe a -> Maybe a -> Maybe a
findJust :: forall a. Maybe a -> Maybe a -> Maybe a
findJust Maybe a
ma Maybe a
mb = forall (m :: * -> *) a. Monad m => m (m a) -> m a
join forall a b. (a -> b) -> a -> b
$ forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Maybe a
find forall a. Maybe a -> Bool
isJust ([Maybe a
ma, Maybe a
mb] :: [Maybe a])