{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE MultiWayIf #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE Safe #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeFamilies #-}

-- |
-- Module      :  Text.Megaparsec.Stream
-- Copyright   :  © 2015–present Megaparsec contributors
-- License     :  FreeBSD
--
-- Maintainer  :  Mark Karpov <markkarpov92@gmail.com>
-- Stability   :  experimental
-- Portability :  portable
--
-- Megaparsec's input stream facilities.
--
-- You probably do not want to import this module directly because
-- "Text.Megaparsec" re-exports it anyway.
--
-- @since 6.0.0
module Text.Megaparsec.Stream
  ( Stream (..),
    VisualStream (..),
    TraversableStream (..),
  )
where

import qualified Data.ByteString as B
import qualified Data.ByteString.Char8 as B8
import qualified Data.ByteString.Lazy as BL
import qualified Data.ByteString.Lazy.Char8 as BL8
import Data.Char (chr)
import Data.Foldable (foldl', toList)
import Data.Kind (Type)
import Data.List.NonEmpty (NonEmpty (..))
import qualified Data.List.NonEmpty as NE
import Data.Maybe (fromMaybe)
import Data.Proxy
import qualified Data.Sequence as S
import qualified Data.Text as T
import qualified Data.Text.Lazy as TL
import Data.Word (Word8)
import Text.Megaparsec.Pos
import Text.Megaparsec.State

-- | Type class for inputs that can be consumed by the library.
--
-- __Note__: before the version /9.0.0/ the class included the methods from
-- 'VisualStream' and 'TraversableStream'.
class (Ord (Token s), Ord (Tokens s)) => Stream s where
  -- | Type of token in the stream.
  type Token s :: Type

  -- | Type of “chunk” of the stream.
  type Tokens s :: Type

  -- | Lift a single token to chunk of the stream. The default
  -- implementation is:
  --
  -- > tokenToChunk pxy = tokensToChunk pxy . pure
  --
  -- However for some types of stream there may be a more efficient way to
  -- lift.
  tokenToChunk :: Proxy s -> Token s -> Tokens s
  tokenToChunk Proxy s
pxy = Proxy s -> [Token s] -> Tokens s
forall s. Stream s => Proxy s -> [Token s] -> Tokens s
tokensToChunk Proxy s
pxy ([Token s] -> Tokens s)
-> (Token s -> [Token s]) -> Token s -> Tokens s
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Token s -> [Token s]
forall (f :: * -> *) a. Applicative f => a -> f a
pure

  -- | The first method that establishes isomorphism between list of tokens
  -- and chunk of the stream. Valid implementation should satisfy:
  --
  -- > chunkToTokens pxy (tokensToChunk pxy ts) == ts
  tokensToChunk :: Proxy s -> [Token s] -> Tokens s

  -- | The second method that establishes isomorphism between list of tokens
  -- and chunk of the stream. Valid implementation should satisfy:
  --
  -- > tokensToChunk pxy (chunkToTokens pxy chunk) == chunk
  chunkToTokens :: Proxy s -> Tokens s -> [Token s]

  -- | Return length of a chunk of the stream.
  chunkLength :: Proxy s -> Tokens s -> Int

  -- | Check if a chunk of the stream is empty. The default implementation
  -- is in terms of the more general 'chunkLength':
  --
  -- > chunkEmpty pxy ts = chunkLength pxy ts <= 0
  --
  -- However for many streams there may be a more efficient implementation.
  chunkEmpty :: Proxy s -> Tokens s -> Bool
  chunkEmpty Proxy s
pxy Tokens s
ts = Proxy s -> Tokens s -> Int
forall s. Stream s => Proxy s -> Tokens s -> Int
chunkLength Proxy s
pxy Tokens s
ts Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
<= Int
0

  -- | Extract a single token form the stream. Return 'Nothing' if the
  -- stream is empty.
  take1_ :: s -> Maybe (Token s, s)

  -- | @'takeN_' n s@ should try to extract a chunk of length @n@, or if the
  -- stream is too short, the rest of the stream. Valid implementation
  -- should follow the rules:
  --
  --     * If the requested length @n@ is 0 (or less), 'Nothing' should
  --       never be returned, instead @'Just' (\"\", s)@ should be returned,
  --       where @\"\"@ stands for the empty chunk, and @s@ is the original
  --       stream (second argument).
  --     * If the requested length is greater than 0 and the stream is
  --       empty, 'Nothing' should be returned indicating end of input.
  --     * In other cases, take chunk of length @n@ (or shorter if the
  --       stream is not long enough) from the input stream and return the
  --       chunk along with the rest of the stream.
  takeN_ :: Int -> s -> Maybe (Tokens s, s)

  -- | Extract chunk of the stream taking tokens while the supplied
  -- predicate returns 'True'. Return the chunk and the rest of the stream.
  --
  -- For many types of streams, the method allows for significant
  -- performance improvements, although it is not strictly necessary from
  -- conceptual point of view.
  takeWhile_ :: (Token s -> Bool) -> s -> (Tokens s, s)

-- | @since 9.0.0
instance Ord a => Stream [a] where
  type Token [a] = a
  type Tokens [a] = [a]
  tokenToChunk :: Proxy [a] -> Token [a] -> Tokens [a]
tokenToChunk Proxy [a]
Proxy = Token [a] -> Tokens [a]
forall (f :: * -> *) a. Applicative f => a -> f a
pure
  tokensToChunk :: Proxy [a] -> [Token [a]] -> Tokens [a]
tokensToChunk Proxy [a]
Proxy = [Token [a]] -> Tokens [a]
forall a. a -> a
id
  chunkToTokens :: Proxy [a] -> Tokens [a] -> [Token [a]]
chunkToTokens Proxy [a]
Proxy = Tokens [a] -> [Token [a]]
forall a. a -> a
id
  chunkLength :: Proxy [a] -> Tokens [a] -> Int
chunkLength Proxy [a]
Proxy = Tokens [a] -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length
  chunkEmpty :: Proxy [a] -> Tokens [a] -> Bool
chunkEmpty Proxy [a]
Proxy = Tokens [a] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null
  take1_ :: [a] -> Maybe (Token [a], [a])
take1_ [] = Maybe (Token [a], [a])
forall a. Maybe a
Nothing
  take1_ (a
t : [a]
ts) = (a, [a]) -> Maybe (a, [a])
forall a. a -> Maybe a
Just (a
t, [a]
ts)
  takeN_ :: Int -> [a] -> Maybe (Tokens [a], [a])
takeN_ Int
n [a]
s
    | Int
n Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
<= Int
0 = ([a], [a]) -> Maybe ([a], [a])
forall a. a -> Maybe a
Just ([], [a]
s)
    | [a] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [a]
s = Maybe (Tokens [a], [a])
forall a. Maybe a
Nothing
    | Bool
otherwise = ([a], [a]) -> Maybe ([a], [a])
forall a. a -> Maybe a
Just (Int -> [a] -> ([a], [a])
forall a. Int -> [a] -> ([a], [a])
splitAt Int
n [a]
s)
  takeWhile_ :: (Token [a] -> Bool) -> [a] -> (Tokens [a], [a])
takeWhile_ = (Token [a] -> Bool) -> [a] -> (Tokens [a], [a])
forall a. (a -> Bool) -> [a] -> ([a], [a])
span

-- | @since 9.0.0
instance Ord a => Stream (S.Seq a) where
  type Token (S.Seq a) = a
  type Tokens (S.Seq a) = S.Seq a
  tokenToChunk :: Proxy (Seq a) -> Token (Seq a) -> Tokens (Seq a)
tokenToChunk Proxy (Seq a)
Proxy = Token (Seq a) -> Tokens (Seq a)
forall (f :: * -> *) a. Applicative f => a -> f a
pure
  tokensToChunk :: Proxy (Seq a) -> [Token (Seq a)] -> Tokens (Seq a)
tokensToChunk Proxy (Seq a)
Proxy = [Token (Seq a)] -> Tokens (Seq a)
forall a. [a] -> Seq a
S.fromList
  chunkToTokens :: Proxy (Seq a) -> Tokens (Seq a) -> [Token (Seq a)]
chunkToTokens Proxy (Seq a)
Proxy = Tokens (Seq a) -> [Token (Seq a)]
forall (t :: * -> *) a. Foldable t => t a -> [a]
toList
  chunkLength :: Proxy (Seq a) -> Tokens (Seq a) -> Int
chunkLength Proxy (Seq a)
Proxy = Tokens (Seq a) -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length
  chunkEmpty :: Proxy (Seq a) -> Tokens (Seq a) -> Bool
chunkEmpty Proxy (Seq a)
Proxy = Tokens (Seq a) -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null
  take1_ :: Seq a -> Maybe (Token (Seq a), Seq a)
take1_ Seq a
S.Empty = Maybe (Token (Seq a), Seq a)
forall a. Maybe a
Nothing
  take1_ (a
t S.:<| Seq a
ts) = (a, Seq a) -> Maybe (a, Seq a)
forall a. a -> Maybe a
Just (a
t, Seq a
ts)
  takeN_ :: Int -> Seq a -> Maybe (Tokens (Seq a), Seq a)
takeN_ Int
n Seq a
s
    | Int
n Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
<= Int
0 = (Seq a, Seq a) -> Maybe (Seq a, Seq a)
forall a. a -> Maybe a
Just (Seq a
forall a. Seq a
S.empty, Seq a
s)
    | Seq a -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null Seq a
s = Maybe (Tokens (Seq a), Seq a)
forall a. Maybe a
Nothing
    | Bool
otherwise = (Seq a, Seq a) -> Maybe (Seq a, Seq a)
forall a. a -> Maybe a
Just (Int -> Seq a -> (Seq a, Seq a)
forall a. Int -> Seq a -> (Seq a, Seq a)
S.splitAt Int
n Seq a
s)
  takeWhile_ :: (Token (Seq a) -> Bool) -> Seq a -> (Tokens (Seq a), Seq a)
takeWhile_ = (Token (Seq a) -> Bool) -> Seq a -> (Tokens (Seq a), Seq a)
forall a. (a -> Bool) -> Seq a -> (Seq a, Seq a)
S.spanl

instance Stream B.ByteString where
  type Token B.ByteString = Word8
  type Tokens B.ByteString = B.ByteString
  tokenToChunk :: Proxy ByteString -> Token ByteString -> Tokens ByteString
tokenToChunk Proxy ByteString
Proxy = Word8 -> ByteString
Token ByteString -> Tokens ByteString
B.singleton
  tokensToChunk :: Proxy ByteString -> [Token ByteString] -> Tokens ByteString
tokensToChunk Proxy ByteString
Proxy = [Word8] -> ByteString
[Token ByteString] -> Tokens ByteString
B.pack
  chunkToTokens :: Proxy ByteString -> Tokens ByteString -> [Token ByteString]
chunkToTokens Proxy ByteString
Proxy = ByteString -> [Word8]
Tokens ByteString -> [Token ByteString]
B.unpack
  chunkLength :: Proxy ByteString -> Tokens ByteString -> Int
chunkLength Proxy ByteString
Proxy = ByteString -> Int
Tokens ByteString -> Int
B.length
  chunkEmpty :: Proxy ByteString -> Tokens ByteString -> Bool
chunkEmpty Proxy ByteString
Proxy = ByteString -> Bool
Tokens ByteString -> Bool
B.null
  take1_ :: ByteString -> Maybe (Token ByteString, ByteString)
take1_ = ByteString -> Maybe (Word8, ByteString)
ByteString -> Maybe (Token ByteString, ByteString)
B.uncons
  takeN_ :: Int -> ByteString -> Maybe (Tokens ByteString, ByteString)
takeN_ Int
n ByteString
s
    | Int
n Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
<= Int
0 = (ByteString, ByteString) -> Maybe (ByteString, ByteString)
forall a. a -> Maybe a
Just (ByteString
B.empty, ByteString
s)
    | ByteString -> Bool
B.null ByteString
s = Maybe (Tokens ByteString, ByteString)
forall a. Maybe a
Nothing
    | Bool
otherwise = (ByteString, ByteString) -> Maybe (ByteString, ByteString)
forall a. a -> Maybe a
Just (Int -> ByteString -> (ByteString, ByteString)
B.splitAt Int
n ByteString
s)
  takeWhile_ :: (Token ByteString -> Bool)
-> ByteString -> (Tokens ByteString, ByteString)
takeWhile_ = (Word8 -> Bool) -> ByteString -> (ByteString, ByteString)
(Token ByteString -> Bool)
-> ByteString -> (Tokens ByteString, ByteString)
B.span

instance Stream BL.ByteString where
  type Token BL.ByteString = Word8
  type Tokens BL.ByteString = BL.ByteString
  tokenToChunk :: Proxy ByteString -> Token ByteString -> Tokens ByteString
tokenToChunk Proxy ByteString
Proxy = Word8 -> ByteString
Token ByteString -> Tokens ByteString
BL.singleton
  tokensToChunk :: Proxy ByteString -> [Token ByteString] -> Tokens ByteString
tokensToChunk Proxy ByteString
Proxy = [Word8] -> ByteString
[Token ByteString] -> Tokens ByteString
BL.pack
  chunkToTokens :: Proxy ByteString -> Tokens ByteString -> [Token ByteString]
chunkToTokens Proxy ByteString
Proxy = ByteString -> [Word8]
Tokens ByteString -> [Token ByteString]
BL.unpack
  chunkLength :: Proxy ByteString -> Tokens ByteString -> Int
chunkLength Proxy ByteString
Proxy = Int64 -> Int
forall a b. (Integral a, Num b) => a -> b
fromIntegral (Int64 -> Int) -> (ByteString -> Int64) -> ByteString -> Int
forall b c a. (b -> c) -> (a -> b) -> a -> c
. ByteString -> Int64
BL.length
  chunkEmpty :: Proxy ByteString -> Tokens ByteString -> Bool
chunkEmpty Proxy ByteString
Proxy = ByteString -> Bool
Tokens ByteString -> Bool
BL.null
  take1_ :: ByteString -> Maybe (Token ByteString, ByteString)
take1_ = ByteString -> Maybe (Word8, ByteString)
ByteString -> Maybe (Token ByteString, ByteString)
BL.uncons
  takeN_ :: Int -> ByteString -> Maybe (Tokens ByteString, ByteString)
takeN_ Int
n ByteString
s
    | Int
n Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
<= Int
0 = (ByteString, ByteString) -> Maybe (ByteString, ByteString)
forall a. a -> Maybe a
Just (ByteString
BL.empty, ByteString
s)
    | ByteString -> Bool
BL.null ByteString
s = Maybe (Tokens ByteString, ByteString)
forall a. Maybe a
Nothing
    | Bool
otherwise = (ByteString, ByteString) -> Maybe (ByteString, ByteString)
forall a. a -> Maybe a
Just (Int64 -> ByteString -> (ByteString, ByteString)
BL.splitAt (Int -> Int64
forall a b. (Integral a, Num b) => a -> b
fromIntegral Int
n) ByteString
s)
  takeWhile_ :: (Token ByteString -> Bool)
-> ByteString -> (Tokens ByteString, ByteString)
takeWhile_ = (Word8 -> Bool) -> ByteString -> (ByteString, ByteString)
(Token ByteString -> Bool)
-> ByteString -> (Tokens ByteString, ByteString)
BL.span

instance Stream T.Text where
  type Token T.Text = Char
  type Tokens T.Text = T.Text
  tokenToChunk :: Proxy Text -> Token Text -> Tokens Text
tokenToChunk Proxy Text
Proxy = Char -> Text
Token Text -> Tokens Text
T.singleton
  tokensToChunk :: Proxy Text -> [Token Text] -> Tokens Text
tokensToChunk Proxy Text
Proxy = String -> Text
[Token Text] -> Tokens Text
T.pack
  chunkToTokens :: Proxy Text -> Tokens Text -> [Token Text]
chunkToTokens Proxy Text
Proxy = Text -> String
Tokens Text -> [Token Text]
T.unpack
  chunkLength :: Proxy Text -> Tokens Text -> Int
chunkLength Proxy Text
Proxy = Text -> Int
Tokens Text -> Int
T.length
  chunkEmpty :: Proxy Text -> Tokens Text -> Bool
chunkEmpty Proxy Text
Proxy = Text -> Bool
Tokens Text -> Bool
T.null
  take1_ :: Text -> Maybe (Token Text, Text)
take1_ = Text -> Maybe (Char, Text)
Text -> Maybe (Token Text, Text)
T.uncons
  takeN_ :: Int -> Text -> Maybe (Tokens Text, Text)
takeN_ Int
n Text
s
    | Int
n Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
<= Int
0 = (Text, Text) -> Maybe (Text, Text)
forall a. a -> Maybe a
Just (Text
T.empty, Text
s)
    | Text -> Bool
T.null Text
s = Maybe (Tokens Text, Text)
forall a. Maybe a
Nothing
    | Bool
otherwise = (Text, Text) -> Maybe (Text, Text)
forall a. a -> Maybe a
Just (Int -> Text -> (Text, Text)
T.splitAt Int
n Text
s)
  takeWhile_ :: (Token Text -> Bool) -> Text -> (Tokens Text, Text)
takeWhile_ = (Char -> Bool) -> Text -> (Text, Text)
(Token Text -> Bool) -> Text -> (Tokens Text, Text)
T.span

instance Stream TL.Text where
  type Token TL.Text = Char
  type Tokens TL.Text = TL.Text
  tokenToChunk :: Proxy Text -> Token Text -> Tokens Text
tokenToChunk Proxy Text
Proxy = Char -> Text
Token Text -> Tokens Text
TL.singleton
  tokensToChunk :: Proxy Text -> [Token Text] -> Tokens Text
tokensToChunk Proxy Text
Proxy = String -> Text
[Token Text] -> Tokens Text
TL.pack
  chunkToTokens :: Proxy Text -> Tokens Text -> [Token Text]
chunkToTokens Proxy Text
Proxy = Text -> String
Tokens Text -> [Token Text]
TL.unpack
  chunkLength :: Proxy Text -> Tokens Text -> Int
chunkLength Proxy Text
Proxy = Int64 -> Int
forall a b. (Integral a, Num b) => a -> b
fromIntegral (Int64 -> Int) -> (Text -> Int64) -> Text -> Int
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Text -> Int64
TL.length
  chunkEmpty :: Proxy Text -> Tokens Text -> Bool
chunkEmpty Proxy Text
Proxy = Text -> Bool
Tokens Text -> Bool
TL.null
  take1_ :: Text -> Maybe (Token Text, Text)
take1_ = Text -> Maybe (Char, Text)
Text -> Maybe (Token Text, Text)
TL.uncons
  takeN_ :: Int -> Text -> Maybe (Tokens Text, Text)
takeN_ Int
n Text
s
    | Int
n Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
<= Int
0 = (Text, Text) -> Maybe (Text, Text)
forall a. a -> Maybe a
Just (Text
TL.empty, Text
s)
    | Text -> Bool
TL.null Text
s = Maybe (Tokens Text, Text)
forall a. Maybe a
Nothing
    | Bool
otherwise = (Text, Text) -> Maybe (Text, Text)
forall a. a -> Maybe a
Just (Int64 -> Text -> (Text, Text)
TL.splitAt (Int -> Int64
forall a b. (Integral a, Num b) => a -> b
fromIntegral Int
n) Text
s)
  takeWhile_ :: (Token Text -> Bool) -> Text -> (Tokens Text, Text)
takeWhile_ = (Char -> Bool) -> Text -> (Text, Text)
(Token Text -> Bool) -> Text -> (Tokens Text, Text)
TL.span

-- | Type class for inputs that can also be used for debugging.
--
-- @since 9.0.0
class Stream s => VisualStream s where
  -- | Pretty-print non-empty stream of tokens. This function is also used
  -- to print single tokens (represented as singleton lists).
  --
  -- @since 7.0.0
  showTokens :: Proxy s -> NonEmpty (Token s) -> String

  -- | Return the number of characters that a non-empty stream of tokens
  -- spans. The default implementation is sufficient if every token spans
  -- exactly 1 character.
  --
  -- @since 8.0.0
  tokensLength :: Proxy s -> NonEmpty (Token s) -> Int
  tokensLength Proxy s
Proxy = NonEmpty (Token s) -> Int
forall a. NonEmpty a -> Int
NE.length

instance VisualStream String where
  showTokens :: Proxy String -> NonEmpty (Token String) -> String
showTokens Proxy String
Proxy = NonEmpty Char -> String
NonEmpty (Token String) -> String
stringPretty

instance VisualStream B.ByteString where
  showTokens :: Proxy ByteString -> NonEmpty (Token ByteString) -> String
showTokens Proxy ByteString
Proxy = NonEmpty Char -> String
stringPretty (NonEmpty Char -> String)
-> (NonEmpty Word8 -> NonEmpty Char) -> NonEmpty Word8 -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (Word8 -> Char) -> NonEmpty Word8 -> NonEmpty Char
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap (Int -> Char
chr (Int -> Char) -> (Word8 -> Int) -> Word8 -> Char
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Word8 -> Int
forall a b. (Integral a, Num b) => a -> b
fromIntegral)

instance VisualStream BL.ByteString where
  showTokens :: Proxy ByteString -> NonEmpty (Token ByteString) -> String
showTokens Proxy ByteString
Proxy = NonEmpty Char -> String
stringPretty (NonEmpty Char -> String)
-> (NonEmpty Word8 -> NonEmpty Char) -> NonEmpty Word8 -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (Word8 -> Char) -> NonEmpty Word8 -> NonEmpty Char
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap (Int -> Char
chr (Int -> Char) -> (Word8 -> Int) -> Word8 -> Char
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Word8 -> Int
forall a b. (Integral a, Num b) => a -> b
fromIntegral)

instance VisualStream T.Text where
  showTokens :: Proxy Text -> NonEmpty (Token Text) -> String
showTokens Proxy Text
Proxy = NonEmpty Char -> String
NonEmpty (Token Text) -> String
stringPretty

instance VisualStream TL.Text where
  showTokens :: Proxy Text -> NonEmpty (Token Text) -> String
showTokens Proxy Text
Proxy = NonEmpty Char -> String
NonEmpty (Token Text) -> String
stringPretty

-- | Type class for inputs that can also be used for error reporting.
--
-- @since 9.0.0
class Stream s => TraversableStream s where
  {-# MINIMAL reachOffset | reachOffsetNoLine #-}

  -- | Given an offset @o@ and initial 'PosState', adjust the state in such
  -- a way that it starts at the offset.
  --
  -- Return two values (in order):
  --
  --     * 'Maybe' 'String' representing the line on which the given offset
  --       @o@ is located. It can be omitted (i.e. 'Nothing'); in that case
  --       error reporting functions will not show offending lines. If
  --       returned, the line should satisfy a number of conditions that are
  --       described below.
  --     * The updated 'PosState' which can be in turn used to locate
  --       another offset @o'@ given that @o' >= o@.
  --
  -- The 'String' representing the offending line in input stream should
  -- satisfy the following:
  --
  --     * It should adequately represent location of token at the offset of
  --       interest, that is, character at 'sourceColumn' of the returned
  --       'SourcePos' should correspond to the token at the offset @o@.
  --     * It should not include the newline at the end.
  --     * It should not be empty, if the line happens to be empty, it
  --       should be replaced with the string @\"\<empty line\>\"@.
  --     * Tab characters should be replaced by appropriate number of
  --       spaces, which is determined by the 'pstateTabWidth' field of
  --       'PosState'.
  --
  -- __Note__: type signature of the function was changed in the version
  -- /9.0.0/.
  --
  -- @since 7.0.0
  reachOffset ::
    -- | Offset to reach
    Int ->
    -- | Initial 'PosState' to use
    PosState s ->
    -- | See the description of the function
    (Maybe String, PosState s)
  reachOffset Int
o PosState s
pst =
    (Maybe String
forall a. Maybe a
Nothing, Int -> PosState s -> PosState s
forall s. TraversableStream s => Int -> PosState s -> PosState s
reachOffsetNoLine Int
o PosState s
pst)

  -- | A version of 'reachOffset' that may be faster because it doesn't need
  -- to fetch the line at which the given offset in located.
  --
  -- The default implementation is this:
  --
  -- > reachOffsetNoLine o pst =
  -- >   snd (reachOffset o pst)
  --
  -- __Note__: type signature of the function was changed in the version
  -- /8.0.0/.
  --
  -- @since 7.0.0
  reachOffsetNoLine ::
    -- | Offset to reach
    Int ->
    -- | Initial 'PosState' to use
    PosState s ->
    -- | Reached source position and updated state
    PosState s
  reachOffsetNoLine Int
o PosState s
pst =
    (Maybe String, PosState s) -> PosState s
forall a b. (a, b) -> b
snd (Int -> PosState s -> (Maybe String, PosState s)
forall s.
TraversableStream s =>
Int -> PosState s -> (Maybe String, PosState s)
reachOffset Int
o PosState s
pst)

instance TraversableStream String where
  -- NOTE Do not eta-reduce these (breaks inlining)
  reachOffset :: Int -> PosState String -> (Maybe String, PosState String)
reachOffset Int
o PosState String
pst =
    (Int -> String -> (Tokens String, String))
-> (forall b. (b -> Token String -> b) -> b -> Tokens String -> b)
-> (Tokens String -> String)
-> (Token String -> Char)
-> (Token String, Token String)
-> Int
-> PosState String
-> (Maybe String, PosState String)
forall s.
Stream s =>
(Int -> s -> (Tokens s, s))
-> (forall b. (b -> Token s -> b) -> b -> Tokens s -> b)
-> (Tokens s -> String)
-> (Token s -> Char)
-> (Token s, Token s)
-> Int
-> PosState s
-> (Maybe String, PosState s)
reachOffset' Int -> String -> (Tokens String, String)
forall a. Int -> [a] -> ([a], [a])
splitAt forall b. (b -> Token String -> b) -> b -> Tokens String -> b
forall (t :: * -> *) b a.
Foldable t =>
(b -> a -> b) -> b -> t a -> b
foldl' Tokens String -> String
forall a. a -> a
id Token String -> Char
forall a. a -> a
id (Char
Token String
'\n', Char
Token String
'\t') Int
o PosState String
pst
  reachOffsetNoLine :: Int -> PosState String -> PosState String
reachOffsetNoLine Int
o PosState String
pst =
    (Int -> String -> (Tokens String, String))
-> (forall b. (b -> Token String -> b) -> b -> Tokens String -> b)
-> (Token String, Token String)
-> Int
-> PosState String
-> PosState String
forall s.
Stream s =>
(Int -> s -> (Tokens s, s))
-> (forall b. (b -> Token s -> b) -> b -> Tokens s -> b)
-> (Token s, Token s)
-> Int
-> PosState s
-> PosState s
reachOffsetNoLine' Int -> String -> (Tokens String, String)
forall a. Int -> [a] -> ([a], [a])
splitAt forall b. (b -> Token String -> b) -> b -> Tokens String -> b
forall (t :: * -> *) b a.
Foldable t =>
(b -> a -> b) -> b -> t a -> b
foldl' (Char
Token String
'\n', Char
Token String
'\t') Int
o PosState String
pst

instance TraversableStream B.ByteString where
  -- NOTE Do not eta-reduce these (breaks inlining)
  reachOffset :: Int -> PosState ByteString -> (Maybe String, PosState ByteString)
reachOffset Int
o PosState ByteString
pst =
    (Int -> ByteString -> (Tokens ByteString, ByteString))
-> (forall b.
    (b -> Token ByteString -> b) -> b -> Tokens ByteString -> b)
-> (Tokens ByteString -> String)
-> (Token ByteString -> Char)
-> (Token ByteString, Token ByteString)
-> Int
-> PosState ByteString
-> (Maybe String, PosState ByteString)
forall s.
Stream s =>
(Int -> s -> (Tokens s, s))
-> (forall b. (b -> Token s -> b) -> b -> Tokens s -> b)
-> (Tokens s -> String)
-> (Token s -> Char)
-> (Token s, Token s)
-> Int
-> PosState s
-> (Maybe String, PosState s)
reachOffset' Int -> ByteString -> (ByteString, ByteString)
Int -> ByteString -> (Tokens ByteString, ByteString)
B.splitAt forall a. (a -> Word8 -> a) -> a -> ByteString -> a
forall b.
(b -> Token ByteString -> b) -> b -> Tokens ByteString -> b
B.foldl' ByteString -> String
Tokens ByteString -> String
B8.unpack (Int -> Char
chr (Int -> Char) -> (Word8 -> Int) -> Word8 -> Char
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Word8 -> Int
forall a b. (Integral a, Num b) => a -> b
fromIntegral) (Token ByteString
10, Token ByteString
9) Int
o PosState ByteString
pst
  reachOffsetNoLine :: Int -> PosState ByteString -> PosState ByteString
reachOffsetNoLine Int
o PosState ByteString
pst =
    (Int -> ByteString -> (Tokens ByteString, ByteString))
-> (forall b.
    (b -> Token ByteString -> b) -> b -> Tokens ByteString -> b)
-> (Token ByteString, Token ByteString)
-> Int
-> PosState ByteString
-> PosState ByteString
forall s.
Stream s =>
(Int -> s -> (Tokens s, s))
-> (forall b. (b -> Token s -> b) -> b -> Tokens s -> b)
-> (Token s, Token s)
-> Int
-> PosState s
-> PosState s
reachOffsetNoLine' Int -> ByteString -> (ByteString, ByteString)
Int -> ByteString -> (Tokens ByteString, ByteString)
B.splitAt forall a. (a -> Word8 -> a) -> a -> ByteString -> a
forall b.
(b -> Token ByteString -> b) -> b -> Tokens ByteString -> b
B.foldl' (Token ByteString
10, Token ByteString
9) Int
o PosState ByteString
pst

instance TraversableStream BL.ByteString where
  -- NOTE Do not eta-reduce these (breaks inlining)
  reachOffset :: Int -> PosState ByteString -> (Maybe String, PosState ByteString)
reachOffset Int
o PosState ByteString
pst =
    (Int -> ByteString -> (Tokens ByteString, ByteString))
-> (forall b.
    (b -> Token ByteString -> b) -> b -> Tokens ByteString -> b)
-> (Tokens ByteString -> String)
-> (Token ByteString -> Char)
-> (Token ByteString, Token ByteString)
-> Int
-> PosState ByteString
-> (Maybe String, PosState ByteString)
forall s.
Stream s =>
(Int -> s -> (Tokens s, s))
-> (forall b. (b -> Token s -> b) -> b -> Tokens s -> b)
-> (Tokens s -> String)
-> (Token s -> Char)
-> (Token s, Token s)
-> Int
-> PosState s
-> (Maybe String, PosState s)
reachOffset' Int -> ByteString -> (ByteString, ByteString)
Int -> ByteString -> (Tokens ByteString, ByteString)
splitAtBL forall a. (a -> Word8 -> a) -> a -> ByteString -> a
forall b.
(b -> Token ByteString -> b) -> b -> Tokens ByteString -> b
BL.foldl' ByteString -> String
Tokens ByteString -> String
BL8.unpack (Int -> Char
chr (Int -> Char) -> (Word8 -> Int) -> Word8 -> Char
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Word8 -> Int
forall a b. (Integral a, Num b) => a -> b
fromIntegral) (Token ByteString
10, Token ByteString
9) Int
o PosState ByteString
pst
  reachOffsetNoLine :: Int -> PosState ByteString -> PosState ByteString
reachOffsetNoLine Int
o PosState ByteString
pst =
    (Int -> ByteString -> (Tokens ByteString, ByteString))
-> (forall b.
    (b -> Token ByteString -> b) -> b -> Tokens ByteString -> b)
-> (Token ByteString, Token ByteString)
-> Int
-> PosState ByteString
-> PosState ByteString
forall s.
Stream s =>
(Int -> s -> (Tokens s, s))
-> (forall b. (b -> Token s -> b) -> b -> Tokens s -> b)
-> (Token s, Token s)
-> Int
-> PosState s
-> PosState s
reachOffsetNoLine' Int -> ByteString -> (ByteString, ByteString)
Int -> ByteString -> (Tokens ByteString, ByteString)
splitAtBL forall a. (a -> Word8 -> a) -> a -> ByteString -> a
forall b.
(b -> Token ByteString -> b) -> b -> Tokens ByteString -> b
BL.foldl' (Token ByteString
10, Token ByteString
9) Int
o PosState ByteString
pst

instance TraversableStream T.Text where
  -- NOTE Do not eta-reduce (breaks inlining of reachOffset').
  reachOffset :: Int -> PosState Text -> (Maybe String, PosState Text)
reachOffset Int
o PosState Text
pst =
    (Int -> Text -> (Tokens Text, Text))
-> (forall b. (b -> Token Text -> b) -> b -> Tokens Text -> b)
-> (Tokens Text -> String)
-> (Token Text -> Char)
-> (Token Text, Token Text)
-> Int
-> PosState Text
-> (Maybe String, PosState Text)
forall s.
Stream s =>
(Int -> s -> (Tokens s, s))
-> (forall b. (b -> Token s -> b) -> b -> Tokens s -> b)
-> (Tokens s -> String)
-> (Token s -> Char)
-> (Token s, Token s)
-> Int
-> PosState s
-> (Maybe String, PosState s)
reachOffset' Int -> Text -> (Text, Text)
Int -> Text -> (Tokens Text, Text)
T.splitAt forall a. (a -> Char -> a) -> a -> Text -> a
forall b. (b -> Token Text -> b) -> b -> Tokens Text -> b
T.foldl' Text -> String
Tokens Text -> String
T.unpack Token Text -> Char
forall a. a -> a
id (Char
Token Text
'\n', Char
Token Text
'\t') Int
o PosState Text
pst
  reachOffsetNoLine :: Int -> PosState Text -> PosState Text
reachOffsetNoLine Int
o PosState Text
pst =
    (Int -> Text -> (Tokens Text, Text))
-> (forall b. (b -> Token Text -> b) -> b -> Tokens Text -> b)
-> (Token Text, Token Text)
-> Int
-> PosState Text
-> PosState Text
forall s.
Stream s =>
(Int -> s -> (Tokens s, s))
-> (forall b. (b -> Token s -> b) -> b -> Tokens s -> b)
-> (Token s, Token s)
-> Int
-> PosState s
-> PosState s
reachOffsetNoLine' Int -> Text -> (Text, Text)
Int -> Text -> (Tokens Text, Text)
T.splitAt forall a. (a -> Char -> a) -> a -> Text -> a
forall b. (b -> Token Text -> b) -> b -> Tokens Text -> b
T.foldl' (Char
Token Text
'\n', Char
Token Text
'\t') Int
o PosState Text
pst

instance TraversableStream TL.Text where
  -- NOTE Do not eta-reduce (breaks inlining of reachOffset').
  reachOffset :: Int -> PosState Text -> (Maybe String, PosState Text)
reachOffset Int
o PosState Text
pst =
    (Int -> Text -> (Tokens Text, Text))
-> (forall b. (b -> Token Text -> b) -> b -> Tokens Text -> b)
-> (Tokens Text -> String)
-> (Token Text -> Char)
-> (Token Text, Token Text)
-> Int
-> PosState Text
-> (Maybe String, PosState Text)
forall s.
Stream s =>
(Int -> s -> (Tokens s, s))
-> (forall b. (b -> Token s -> b) -> b -> Tokens s -> b)
-> (Tokens s -> String)
-> (Token s -> Char)
-> (Token s, Token s)
-> Int
-> PosState s
-> (Maybe String, PosState s)
reachOffset' Int -> Text -> (Text, Text)
Int -> Text -> (Tokens Text, Text)
splitAtTL forall a. (a -> Char -> a) -> a -> Text -> a
forall b. (b -> Token Text -> b) -> b -> Tokens Text -> b
TL.foldl' Text -> String
Tokens Text -> String
TL.unpack Token Text -> Char
forall a. a -> a
id (Char
Token Text
'\n', Char
Token Text
'\t') Int
o PosState Text
pst
  reachOffsetNoLine :: Int -> PosState Text -> PosState Text
reachOffsetNoLine Int
o PosState Text
pst =
    (Int -> Text -> (Tokens Text, Text))
-> (forall b. (b -> Token Text -> b) -> b -> Tokens Text -> b)
-> (Token Text, Token Text)
-> Int
-> PosState Text
-> PosState Text
forall s.
Stream s =>
(Int -> s -> (Tokens s, s))
-> (forall b. (b -> Token s -> b) -> b -> Tokens s -> b)
-> (Token s, Token s)
-> Int
-> PosState s
-> PosState s
reachOffsetNoLine' Int -> Text -> (Text, Text)
Int -> Text -> (Tokens Text, Text)
splitAtTL forall a. (a -> Char -> a) -> a -> Text -> a
forall b. (b -> Token Text -> b) -> b -> Tokens Text -> b
TL.foldl' (Char
Token Text
'\n', Char
Token Text
'\t') Int
o PosState Text
pst

----------------------------------------------------------------------------
-- Helpers

-- | An internal helper state type combining a difference 'String' and an
-- unboxed 'SourcePos'.
data St = St SourcePos ShowS

-- | A helper definition to facilitate defining 'reachOffset' for various
-- stream types.
reachOffset' ::
  forall s.
  Stream s =>
  -- | How to split input stream at given offset
  (Int -> s -> (Tokens s, s)) ->
  -- | How to fold over input stream
  (forall b. (b -> Token s -> b) -> b -> Tokens s -> b) ->
  -- | How to convert chunk of input stream into a 'String'
  (Tokens s -> String) ->
  -- | How to convert a token into a 'Char'
  (Token s -> Char) ->
  -- | Newline token and tab token
  (Token s, Token s) ->
  -- | Offset to reach
  Int ->
  -- | Initial 'PosState' to use
  PosState s ->
  -- | Line at which 'SourcePos' is located, updated 'PosState'
  (Maybe String, PosState s)
reachOffset' :: (Int -> s -> (Tokens s, s))
-> (forall b. (b -> Token s -> b) -> b -> Tokens s -> b)
-> (Tokens s -> String)
-> (Token s -> Char)
-> (Token s, Token s)
-> Int
-> PosState s
-> (Maybe String, PosState s)
reachOffset'
  Int -> s -> (Tokens s, s)
splitAt'
  forall b. (b -> Token s -> b) -> b -> Tokens s -> b
foldl''
  Tokens s -> String
fromToks
  Token s -> Char
fromTok
  (Token s
newlineTok, Token s
tabTok)
  Int
o
  PosState {s
Int
String
SourcePos
Pos
pstateLinePrefix :: forall s. PosState s -> String
pstateTabWidth :: forall s. PosState s -> Pos
pstateSourcePos :: forall s. PosState s -> SourcePos
pstateOffset :: forall s. PosState s -> Int
pstateInput :: forall s. PosState s -> s
pstateLinePrefix :: String
pstateTabWidth :: Pos
pstateSourcePos :: SourcePos
pstateOffset :: Int
pstateInput :: s
..} =
    ( String -> Maybe String
forall a. a -> Maybe a
Just (String -> Maybe String) -> String -> Maybe String
forall a b. (a -> b) -> a -> b
$ case Pos -> String -> String
expandTab Pos
pstateTabWidth
        (String -> String)
-> ((Tokens s, s) -> String) -> (Tokens s, s) -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String
addPrefix
        (String -> String)
-> ((Tokens s, s) -> String) -> (Tokens s, s) -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> String
f
        (String -> String)
-> ((Tokens s, s) -> String) -> (Tokens s, s) -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Tokens s -> String
fromToks
        (Tokens s -> String)
-> ((Tokens s, s) -> Tokens s) -> (Tokens s, s) -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (Tokens s, s) -> Tokens s
forall a b. (a, b) -> a
fst
        ((Tokens s, s) -> String) -> (Tokens s, s) -> String
forall a b. (a -> b) -> a -> b
$ (Token s -> Bool) -> s -> (Tokens s, s)
forall s. Stream s => (Token s -> Bool) -> s -> (Tokens s, s)
takeWhile_ (Token s -> Token s -> Bool
forall a. Eq a => a -> a -> Bool
/= Token s
newlineTok) s
post of
        String
"" -> String
"<empty line>"
        String
xs -> String
xs,
      PosState :: forall s. s -> Int -> SourcePos -> Pos -> String -> PosState s
PosState
        { pstateInput :: s
pstateInput = s
post,
          pstateOffset :: Int
pstateOffset = Int -> Int -> Int
forall a. Ord a => a -> a -> a
max Int
pstateOffset Int
o,
          pstateSourcePos :: SourcePos
pstateSourcePos = SourcePos
spos,
          pstateTabWidth :: Pos
pstateTabWidth = Pos
pstateTabWidth,
          pstateLinePrefix :: String
pstateLinePrefix =
            if Bool
sameLine
              then -- NOTE We don't use difference lists here because it's
              -- desirable for 'PosState' to be an instance of 'Eq' and
              -- 'Show'. So we just do appending here. Fortunately several
              -- parse errors on the same line should be relatively rare.
                String
pstateLinePrefix String -> String -> String
forall a. [a] -> [a] -> [a]
++ String -> String
f String
""
              else String -> String
f String
""
        }
    )
    where
      addPrefix :: String -> String
addPrefix String
xs =
        if Bool
sameLine
          then String
pstateLinePrefix String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
xs
          else String
xs
      sameLine :: Bool
sameLine = SourcePos -> Pos
sourceLine SourcePos
spos Pos -> Pos -> Bool
forall a. Eq a => a -> a -> Bool
== SourcePos -> Pos
sourceLine SourcePos
pstateSourcePos
      (Tokens s
pre, s
post) = Int -> s -> (Tokens s, s)
splitAt' (Int
o Int -> Int -> Int
forall a. Num a => a -> a -> a
- Int
pstateOffset) s
pstateInput
      St SourcePos
spos String -> String
f = (St -> Token s -> St) -> St -> Tokens s -> St
forall b. (b -> Token s -> b) -> b -> Tokens s -> b
foldl'' St -> Token s -> St
go (SourcePos -> (String -> String) -> St
St SourcePos
pstateSourcePos String -> String
forall a. a -> a
id) Tokens s
pre
      go :: St -> Token s -> St
go (St SourcePos
apos String -> String
g) Token s
ch =
        let SourcePos String
n Pos
l Pos
c = SourcePos
apos
            c' :: Int
c' = Pos -> Int
unPos Pos
c
            w :: Int
w = Pos -> Int
unPos Pos
pstateTabWidth
         in if
                | Token s
ch Token s -> Token s -> Bool
forall a. Eq a => a -> a -> Bool
== Token s
newlineTok ->
                  SourcePos -> (String -> String) -> St
St
                    (String -> Pos -> Pos -> SourcePos
SourcePos String
n (Pos
l Pos -> Pos -> Pos
forall a. Semigroup a => a -> a -> a
<> Pos
pos1) Pos
pos1)
                    String -> String
forall a. a -> a
id
                | Token s
ch Token s -> Token s -> Bool
forall a. Eq a => a -> a -> Bool
== Token s
tabTok ->
                  SourcePos -> (String -> String) -> St
St
                    (String -> Pos -> Pos -> SourcePos
SourcePos String
n Pos
l (Int -> Pos
mkPos (Int -> Pos) -> Int -> Pos
forall a b. (a -> b) -> a -> b
$ Int
c' Int -> Int -> Int
forall a. Num a => a -> a -> a
+ Int
w Int -> Int -> Int
forall a. Num a => a -> a -> a
- ((Int
c' Int -> Int -> Int
forall a. Num a => a -> a -> a
- Int
1) Int -> Int -> Int
forall a. Integral a => a -> a -> a
`rem` Int
w)))
                    (String -> String
g (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (Token s -> Char
fromTok Token s
ch Char -> String -> String
forall a. a -> [a] -> [a]
:))
                | Bool
otherwise ->
                  SourcePos -> (String -> String) -> St
St
                    (String -> Pos -> Pos -> SourcePos
SourcePos String
n Pos
l (Pos
c Pos -> Pos -> Pos
forall a. Semigroup a => a -> a -> a
<> Pos
pos1))
                    (String -> String
g (String -> String) -> (String -> String) -> String -> String
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (Token s -> Char
fromTok Token s
ch Char -> String -> String
forall a. a -> [a] -> [a]
:))
{-# INLINE reachOffset' #-}

-- | Like 'reachOffset'' but for 'reachOffsetNoLine'.
reachOffsetNoLine' ::
  forall s.
  Stream s =>
  -- | How to split input stream at given offset
  (Int -> s -> (Tokens s, s)) ->
  -- | How to fold over input stream
  (forall b. (b -> Token s -> b) -> b -> Tokens s -> b) ->
  -- | Newline token and tab token
  (Token s, Token s) ->
  -- | Offset to reach
  Int ->
  -- | Initial 'PosState' to use
  PosState s ->
  -- | Updated 'PosState'
  PosState s
reachOffsetNoLine' :: (Int -> s -> (Tokens s, s))
-> (forall b. (b -> Token s -> b) -> b -> Tokens s -> b)
-> (Token s, Token s)
-> Int
-> PosState s
-> PosState s
reachOffsetNoLine'
  Int -> s -> (Tokens s, s)
splitAt'
  forall b. (b -> Token s -> b) -> b -> Tokens s -> b
foldl''
  (Token s
newlineTok, Token s
tabTok)
  Int
o
  PosState {s
Int
String
SourcePos
Pos
pstateLinePrefix :: String
pstateTabWidth :: Pos
pstateSourcePos :: SourcePos
pstateOffset :: Int
pstateInput :: s
pstateLinePrefix :: forall s. PosState s -> String
pstateTabWidth :: forall s. PosState s -> Pos
pstateSourcePos :: forall s. PosState s -> SourcePos
pstateOffset :: forall s. PosState s -> Int
pstateInput :: forall s. PosState s -> s
..} =
    ( PosState :: forall s. s -> Int -> SourcePos -> Pos -> String -> PosState s
PosState
        { pstateInput :: s
pstateInput = s
post,
          pstateOffset :: Int
pstateOffset = Int -> Int -> Int
forall a. Ord a => a -> a -> a
max Int
pstateOffset Int
o,
          pstateSourcePos :: SourcePos
pstateSourcePos = SourcePos
spos,
          pstateTabWidth :: Pos
pstateTabWidth = Pos
pstateTabWidth,
          pstateLinePrefix :: String
pstateLinePrefix = String
pstateLinePrefix
        }
    )
    where
      spos :: SourcePos
spos = (SourcePos -> Token s -> SourcePos)
-> SourcePos -> Tokens s -> SourcePos
forall b. (b -> Token s -> b) -> b -> Tokens s -> b
foldl'' SourcePos -> Token s -> SourcePos
go SourcePos
pstateSourcePos Tokens s
pre
      (Tokens s
pre, s
post) = Int -> s -> (Tokens s, s)
splitAt' (Int
o Int -> Int -> Int
forall a. Num a => a -> a -> a
- Int
pstateOffset) s
pstateInput
      go :: SourcePos -> Token s -> SourcePos
go (SourcePos String
n Pos
l Pos
c) Token s
ch =
        let c' :: Int
c' = Pos -> Int
unPos Pos
c
            w :: Int
w = Pos -> Int
unPos Pos
pstateTabWidth
         in if
                | Token s
ch Token s -> Token s -> Bool
forall a. Eq a => a -> a -> Bool
== Token s
newlineTok ->
                  String -> Pos -> Pos -> SourcePos
SourcePos String
n (Pos
l Pos -> Pos -> Pos
forall a. Semigroup a => a -> a -> a
<> Pos
pos1) Pos
pos1
                | Token s
ch Token s -> Token s -> Bool
forall a. Eq a => a -> a -> Bool
== Token s
tabTok ->
                  String -> Pos -> Pos -> SourcePos
SourcePos String
n Pos
l (Int -> Pos
mkPos (Int -> Pos) -> Int -> Pos
forall a b. (a -> b) -> a -> b
$ Int
c' Int -> Int -> Int
forall a. Num a => a -> a -> a
+ Int
w Int -> Int -> Int
forall a. Num a => a -> a -> a
- ((Int
c' Int -> Int -> Int
forall a. Num a => a -> a -> a
- Int
1) Int -> Int -> Int
forall a. Integral a => a -> a -> a
`rem` Int
w))
                | Bool
otherwise ->
                  String -> Pos -> Pos -> SourcePos
SourcePos String
n Pos
l (Pos
c Pos -> Pos -> Pos
forall a. Semigroup a => a -> a -> a
<> Pos
pos1)
{-# INLINE reachOffsetNoLine' #-}

-- | Like 'BL.splitAt' but accepts the index as an 'Int'.
splitAtBL :: Int -> BL.ByteString -> (BL.ByteString, BL.ByteString)
splitAtBL :: Int -> ByteString -> (ByteString, ByteString)
splitAtBL Int
n = Int64 -> ByteString -> (ByteString, ByteString)
BL.splitAt (Int -> Int64
forall a b. (Integral a, Num b) => a -> b
fromIntegral Int
n)
{-# INLINE splitAtBL #-}

-- | Like 'TL.splitAt' but accepts the index as an 'Int'.
splitAtTL :: Int -> TL.Text -> (TL.Text, TL.Text)
splitAtTL :: Int -> Text -> (Text, Text)
splitAtTL Int
n = Int64 -> Text -> (Text, Text)
TL.splitAt (Int -> Int64
forall a b. (Integral a, Num b) => a -> b
fromIntegral Int
n)
{-# INLINE splitAtTL #-}

-- | @stringPretty s@ returns pretty representation of string @s@. This is
-- used when printing string tokens in error messages.
stringPretty :: NonEmpty Char -> String
stringPretty :: NonEmpty Char -> String
stringPretty (Char
x :| []) = Char -> String
charPretty Char
x
stringPretty (Char
'\r' :| String
"\n") = String
"crlf newline"
stringPretty NonEmpty Char
xs = String
"\"" String -> String -> String
forall a. Semigroup a => a -> a -> a
<> (Char -> String) -> String -> String
forall (t :: * -> *) a b. Foldable t => (a -> [b]) -> t a -> [b]
concatMap Char -> String
f (NonEmpty Char -> String
forall a. NonEmpty a -> [a]
NE.toList NonEmpty Char
xs) String -> String -> String
forall a. Semigroup a => a -> a -> a
<> String
"\""
  where
    f :: Char -> String
f Char
ch =
      case Char -> Maybe String
charPretty' Char
ch of
        Maybe String
Nothing -> [Char
ch]
        Just String
pretty -> String
"<" String -> String -> String
forall a. Semigroup a => a -> a -> a
<> String
pretty String -> String -> String
forall a. Semigroup a => a -> a -> a
<> String
">"

-- | @charPretty ch@ returns user-friendly string representation of given
-- character @ch@, suitable for using in error messages.
charPretty :: Char -> String
charPretty :: Char -> String
charPretty Char
' ' = String
"space"
charPretty Char
ch = String -> Maybe String -> String
forall a. a -> Maybe a -> a
fromMaybe (String
"'" String -> String -> String
forall a. Semigroup a => a -> a -> a
<> [Char
ch] String -> String -> String
forall a. Semigroup a => a -> a -> a
<> String
"'") (Char -> Maybe String
charPretty' Char
ch)

-- | If the given character has a pretty representation, return that,
-- otherwise 'Nothing'. This is an internal helper.
charPretty' :: Char -> Maybe String
charPretty' :: Char -> Maybe String
charPretty' = \case
  Char
'\NUL' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"null"
  Char
'\SOH' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"start of heading"
  Char
'\STX' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"start of text"
  Char
'\ETX' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"end of text"
  Char
'\EOT' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"end of transmission"
  Char
'\ENQ' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"enquiry"
  Char
'\ACK' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"acknowledge"
  Char
'\BEL' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"bell"
  Char
'\BS' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"backspace"
  Char
'\t' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"tab"
  Char
'\n' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"newline"
  Char
'\v' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"vertical tab"
  Char
'\f' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"form feed"
  Char
'\r' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"carriage return"
  Char
'\SO' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"shift out"
  Char
'\SI' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"shift in"
  Char
'\DLE' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"data link escape"
  Char
'\DC1' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"device control one"
  Char
'\DC2' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"device control two"
  Char
'\DC3' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"device control three"
  Char
'\DC4' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"device control four"
  Char
'\NAK' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"negative acknowledge"
  Char
'\SYN' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"synchronous idle"
  Char
'\ETB' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"end of transmission block"
  Char
'\CAN' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"cancel"
  Char
'\EM' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"end of medium"
  Char
'\SUB' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"substitute"
  Char
'\ESC' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"escape"
  Char
'\FS' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"file separator"
  Char
'\GS' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"group separator"
  Char
'\RS' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"record separator"
  Char
'\US' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"unit separator"
  Char
'\DEL' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"delete"
  Char
'\160' -> String -> Maybe String
forall a. a -> Maybe a
Just String
"non-breaking space"
  Char
_ -> Maybe String
forall a. Maybe a
Nothing

-- | Replace tab characters with given number of spaces.
expandTab ::
  Pos ->
  String ->
  String
expandTab :: Pos -> String -> String
expandTab Pos
w' = Int -> String -> String
go Int
0
  where
    go :: Int -> String -> String
go Int
0 [] = []
    go Int
0 (Char
'\t' : String
xs) = Int -> String -> String
go Int
w String
xs
    go Int
0 (Char
x : String
xs) = Char
x Char -> String -> String
forall a. a -> [a] -> [a]
: Int -> String -> String
go Int
0 String
xs
    go Int
n String
xs = Char
' ' Char -> String -> String
forall a. a -> [a] -> [a]
: Int -> String -> String
go (Int
n Int -> Int -> Int
forall a. Num a => a -> a -> a
- Int
1) String
xs
    w :: Int
w = Pos -> Int
unPos Pos
w'