{-# LANGUAGE Trustworthy #-}
{-# LANGUAGE DeriveFunctor, StandaloneDeriving #-}
{-# OPTIONS_HADDOCK hide #-}
{-|
Module      : Text.Gigaparsec.Internal
Description : Internals of Gigaparsec
License     : BSD-3-Clause
Maintainer  : Jamie Willis, Gigaparsec Maintainers
Stability   : unstable

This module does __not__ adhere to PVP, and can change at any time as
required by the maintainers of the library. Use this functionality at your
own risk.

@since 0.1.0.0
-}
module Text.Gigaparsec.Internal (module Text.Gigaparsec.Internal) where

import Text.Gigaparsec.Internal.RT (RT)

import Control.Applicative (Applicative(liftA2), Alternative(empty, (<|>), many, some)) -- liftA2 required until 9.6
import Control.Selective (Selective(select))

{-
Notes:

We are making a stripped back implementation, where there are way fewer generalisations
on the type: for now, no monad transformers, generalised input types, etc etc.
For consistency with other libraries, this is usually called `Parsec`.

Experimentally, it seems like dual-continuation implementations may be
faster than quad-continuation implementations. This will need some more
investigation and benchmarking to be sure about this however. We'll get a
core representation settled before doing any "hard" work (the composite
combinator API, however, can be done whenever).
-}
type Parsec :: * -> *
newtype Parsec a = Parsec {
    forall a.
Parsec a
-> forall r.
   State -> (a -> State -> RT r) -> (State -> RT r) -> RT r
unParsec :: forall r. State
             -> (a -> State -> RT r) -- the good continuation
             -> (State -> RT r)      -- the bad continuation
             -> RT r
  }

deriving stock instance Functor Parsec -- not clear if there is a point to implementing this

instance Applicative Parsec where
  pure :: a -> Parsec a
  pure :: forall a. a -> Parsec a
pure a
x = forall a.
(forall r.
 State -> (a -> State -> RT r) -> (State -> RT r) -> RT r)
-> Parsec a
Parsec forall a b. (a -> b) -> a -> b
$ \State
st a -> State -> RT r
ok State -> RT r
_ -> a -> State -> RT r
ok a
x State
st
  -- Continue with x and no input consumed.

  liftA2 :: (a -> b -> c) -> Parsec a -> Parsec b -> Parsec c
  liftA2 :: forall a b c. (a -> b -> c) -> Parsec a -> Parsec b -> Parsec c
liftA2 a -> b -> c
f (Parsec forall r. State -> (a -> State -> RT r) -> (State -> RT r) -> RT r
p) (Parsec forall r. State -> (b -> State -> RT r) -> (State -> RT r) -> RT r
q) = forall a.
(forall r.
 State -> (a -> State -> RT r) -> (State -> RT r) -> RT r)
-> Parsec a
Parsec forall a b. (a -> b) -> a -> b
$ \State
st c -> State -> RT r
ok State -> RT r
err ->
    let ok' :: a -> State -> RT r
ok' a
x State
st' = forall r. State -> (b -> State -> RT r) -> (State -> RT r) -> RT r
q State
st' (c -> State -> RT r
ok forall b c a. (b -> c) -> (a -> b) -> a -> c
. a -> b -> c
f a
x) State -> RT r
err
    --                    ^^^^^^^^^^
    -- continue with (f x y), where y is the output of q
    in  forall r. State -> (a -> State -> RT r) -> (State -> RT r) -> RT r
p State
st a -> State -> RT r
ok' State -> RT r
err

  (*>) :: Parsec a -> Parsec b -> Parsec b
  *> :: forall a b. Parsec a -> Parsec b -> Parsec b
(*>) = forall (f :: * -> *) a b c.
Applicative f =>
(a -> b -> c) -> f a -> f b -> f c
liftA2 (forall a b. a -> b -> a
const forall a. a -> a
id)

  (<*) :: Parsec a -> Parsec b -> Parsec a
  <* :: forall a b. Parsec a -> Parsec b -> Parsec a
(<*) = forall (f :: * -> *) a b c.
Applicative f =>
(a -> b -> c) -> f a -> f b -> f c
liftA2 forall a b. a -> b -> a
const

  {-# INLINE pure #-}
  {-# INLINE liftA2 #-}
  {-# INLINE (<*) #-}
  {-# INLINE (*>) #-}

instance Selective Parsec where
  select :: Parsec (Either a b) -> Parsec (a -> b) -> Parsec b
  select :: forall a b. Parsec (Either a b) -> Parsec (a -> b) -> Parsec b
select Parsec (Either a b)
p Parsec (a -> b)
q = forall a b c.
Parsec (Either a b)
-> Parsec (a -> c) -> Parsec (b -> c) -> Parsec c
_branch Parsec (Either a b)
p Parsec (a -> b)
q (forall (f :: * -> *) a. Applicative f => a -> f a
pure forall a. a -> a
id)

  {-# INLINE select #-}

{-# INLINE _branch #-}
{-|
This is an internal implementation of `branch`, which is more efficient than
the Selective default `branch`. We should be using this internally, and it
can be dropped if https://github.com/snowleopard/selective/issues/74 is implemented.
-}
_branch :: Parsec (Either a b) -> Parsec (a -> c) -> Parsec (b -> c) -> Parsec c
_branch :: forall a b c.
Parsec (Either a b)
-> Parsec (a -> c) -> Parsec (b -> c) -> Parsec c
_branch (Parsec forall r.
State -> (Either a b -> State -> RT r) -> (State -> RT r) -> RT r
p) (Parsec forall r.
State -> ((a -> c) -> State -> RT r) -> (State -> RT r) -> RT r
q1) (Parsec forall r.
State -> ((b -> c) -> State -> RT r) -> (State -> RT r) -> RT r
q2) = forall a.
(forall r.
 State -> (a -> State -> RT r) -> (State -> RT r) -> RT r)
-> Parsec a
Parsec forall a b. (a -> b) -> a -> b
$ \State
st c -> State -> RT r
ok State -> RT r
err ->
  let ok' :: Either a b -> State -> RT r
ok' Either a b
x State
st' = case Either a b
x of
        Left a
a  -> forall r.
State -> ((a -> c) -> State -> RT r) -> (State -> RT r) -> RT r
q1 State
st' (c -> State -> RT r
ok forall b c a. (b -> c) -> (a -> b) -> a -> c
. (forall a b. (a -> b) -> a -> b
$ a
a)) State -> RT r
err
        --                ^^^^^^^^^^^^
        Right b
b -> forall r.
State -> ((b -> c) -> State -> RT r) -> (State -> RT r) -> RT r
q2 State
st' (c -> State -> RT r
ok forall b c a. (b -> c) -> (a -> b) -> a -> c
. (forall a b. (a -> b) -> a -> b
$ b
b)) State -> RT r
err
        --                ^^^^^^^^^^^^
        -- feed a/b to the function of the good continuation
  in  forall r.
State -> (Either a b -> State -> RT r) -> (State -> RT r) -> RT r
p State
st Either a b -> State -> RT r
ok' State -> RT r
err

instance Monad Parsec where
  return :: a -> Parsec a
  return :: forall a. a -> Parsec a
return = forall (f :: * -> *) a. Applicative f => a -> f a
pure

  (>>=) :: Parsec a -> (a -> Parsec b) -> Parsec b
  Parsec forall r. State -> (a -> State -> RT r) -> (State -> RT r) -> RT r
p >>= :: forall a b. Parsec a -> (a -> Parsec b) -> Parsec b
>>= a -> Parsec b
f = forall a.
(forall r.
 State -> (a -> State -> RT r) -> (State -> RT r) -> RT r)
-> Parsec a
Parsec forall a b. (a -> b) -> a -> b
$ \State
st b -> State -> RT r
ok State -> RT r
err ->
    let ok' :: a -> State -> RT r
ok' a
x State
st' = forall a.
Parsec a
-> forall r.
   State -> (a -> State -> RT r) -> (State -> RT r) -> RT r
unParsec (a -> Parsec b
f a
x) State
st' b -> State -> RT r
ok State -> RT r
err
    --              ^^^^^^^^^^^^^^
    -- get the parser obtained from feeding the output of p to f
    in  forall r. State -> (a -> State -> RT r) -> (State -> RT r) -> RT r
p State
st a -> State -> RT r
ok' State -> RT r
err

  (>>) :: Parsec a -> Parsec b -> Parsec b
  >> :: forall a b. Parsec a -> Parsec b -> Parsec b
(>>) = forall (f :: * -> *) a b. Applicative f => f a -> f b -> f b
(*>)

  {-# INLINE return #-}
  {-# INLINE (>>=) #-}

instance Alternative Parsec where
  empty :: Parsec a
  empty :: forall a. Parsec a
empty = forall a.
(forall r.
 State -> (a -> State -> RT r) -> (State -> RT r) -> RT r)
-> Parsec a
Parsec forall a b. (a -> b) -> a -> b
$ \State
st a -> State -> RT r
_ State -> RT r
err -> State -> RT r
err State
st

  (<|>) :: Parsec a -> Parsec a -> Parsec a
  Parsec forall r. State -> (a -> State -> RT r) -> (State -> RT r) -> RT r
p <|> :: forall a. Parsec a -> Parsec a -> Parsec a
<|> Parsec forall r. State -> (a -> State -> RT r) -> (State -> RT r) -> RT r
q = forall a.
(forall r.
 State -> (a -> State -> RT r) -> (State -> RT r) -> RT r)
-> Parsec a
Parsec forall a b. (a -> b) -> a -> b
$ \State
st a -> State -> RT r
ok State -> RT r
err ->
    let !initConsumed :: Bool
initConsumed = State -> Bool
consumed State
st
        ok' :: a -> State -> RT r
ok' a
x State
st' = a -> State -> RT r
ok a
x (State
st' { consumed :: Bool
consumed = Bool
initConsumed Bool -> Bool -> Bool
|| State -> Bool
consumed State
st' })
          --  ^ revert to old st.consumed if p didn't consume
        err' :: State -> RT r
err' State
st'
          | State -> Bool
consumed State
st' = State -> RT r
err State
st'
          --  ^ fail if p failed *and* consumed
          | Bool
otherwise    = forall r. State -> (a -> State -> RT r) -> (State -> RT r) -> RT r
q (State
st' { consumed :: Bool
consumed = Bool
initConsumed }) a -> State -> RT r
ok State -> RT r
err

    in  forall r. State -> (a -> State -> RT r) -> (State -> RT r) -> RT r
p (State
st { consumed :: Bool
consumed = Bool
False }) a -> State -> RT r
ok' State -> RT r
err'

  many :: Parsec a -> Parsec [a]
  many :: forall a. Parsec a -> Parsec [a]
many = forall a b. (a -> b -> b) -> b -> Parsec a -> Parsec b
manyr (:) []

  some :: Parsec a -> Parsec [a]
  some :: forall a. Parsec a -> Parsec [a]
some = forall a b. (a -> b -> b) -> b -> Parsec a -> Parsec b
somer (:) []

  {-# INLINE empty #-}
  {-# INLINE (<|>) #-}
  {-# INLINE many #-}
  {-# INLINE some #-}

{-# INLINE manyr #-}
manyr :: (a -> b -> b) -> b -> Parsec a -> Parsec b
manyr :: forall a b. (a -> b -> b) -> b -> Parsec a -> Parsec b
manyr a -> b -> b
f b
k Parsec a
p = let go :: Parsec b
go = forall (f :: * -> *) a b c.
Applicative f =>
(a -> b -> c) -> f a -> f b -> f c
liftA2 a -> b -> b
f Parsec a
p Parsec b
go forall (f :: * -> *) a. Alternative f => f a -> f a -> f a
<|> forall (f :: * -> *) a. Applicative f => a -> f a
pure b
k in Parsec b
go

{-# INLINE somer #-}
somer :: (a -> b -> b) -> b -> Parsec a -> Parsec b
somer :: forall a b. (a -> b -> b) -> b -> Parsec a -> Parsec b
somer a -> b -> b
f b
k Parsec a
p = forall (f :: * -> *) a b c.
Applicative f =>
(a -> b -> c) -> f a -> f b -> f c
liftA2 a -> b -> b
f Parsec a
p (forall a b. (a -> b -> b) -> b -> Parsec a -> Parsec b
manyr a -> b -> b
f b
k Parsec a
p)

instance Semigroup m => Semigroup (Parsec m) where
  (<>) :: Parsec m -> Parsec m -> Parsec m
  <> :: Parsec m -> Parsec m -> Parsec m
(<>) = forall (f :: * -> *) a b c.
Applicative f =>
(a -> b -> c) -> f a -> f b -> f c
liftA2 forall a. Semigroup a => a -> a -> a
(<>)

  {-# INLINE (<>) #-}

instance Monoid m => Monoid (Parsec m) where
  mempty :: Parsec m
  mempty :: Parsec m
mempty = forall (f :: * -> *) a. Applicative f => a -> f a
pure forall a. Monoid a => a
mempty

  {-# INLINE mempty #-}

type State :: *
data State = State {
    -- | the input string, in future this may be generalised
    State -> String
input :: !String,
    -- | has the parser consumed input since the last relevant handler?
    State -> Bool
consumed :: !Bool, -- this could be an Int offset instead, perhaps?
    -- | the current line number (incremented by \n)
    State -> Int
line :: {-# UNPACK #-} !Int,
    -- | the current column number (have to settle on a tab handling scheme)
    State -> Int
col  :: {-# UNPACK #-} !Int
  }

emptyState :: String -> State
emptyState :: String -> State
emptyState !String
str = State { input :: String
input = String
str
                        , consumed :: Bool
consumed = Bool
False
                        , line :: Int
line = Int
1
                        , col :: Int
col = Int
1
                        }