{-| This module contains the building blocks used to construct the lexer.
-}
module Agda.Syntax.Parser.LexActions
    ( -- * Main function
      lexToken
      -- * Lex actions
      -- ** General actions
    , token
    , withInterval, withInterval', withInterval_
    , withLayout
    , andThen, skip
    , begin, end, beginWith, endWith
    , begin_, end_
    , lexError
      -- ** Specialized actions
    , keyword, symbol, identifier, literal, literal', integer
      -- * Lex predicates
    , followedBy, eof, inState
    ) where

import Control.Monad.State (modify)

import Data.Bifunctor
import Data.Char
import Data.Foldable (foldl')
import Data.Maybe

import Agda.Syntax.Common (pattern Ranged)
import Agda.Syntax.Parser.Lexer
import Agda.Syntax.Parser.Alex
import Agda.Syntax.Parser.Monad
import Agda.Syntax.Parser.Tokens
import Agda.Syntax.Position
import Agda.Syntax.Literal

import Agda.Utils.List

import Agda.Utils.Impossible

{--------------------------------------------------------------------------
    Scan functions
 --------------------------------------------------------------------------}

-- | Called at the end of a file. Returns 'TokEOF'.
returnEOF :: AlexInput -> Parser Token
returnEOF :: AlexInput -> Parser Token
returnEOF AlexInput{ SrcFile
lexSrcFile :: AlexInput -> SrcFile
lexSrcFile :: SrcFile
lexSrcFile, PositionWithoutFile
lexPos :: AlexInput -> PositionWithoutFile
lexPos :: PositionWithoutFile
lexPos } = do
  -- Andreas, 2018-12-30, issue #3480
  -- The following setLastPos leads to parse error reporting
  -- far away from the interesting position, in particular
  -- if there is a long comment before the EOF.
  -- (Such a long comment is frequent in interactive programming, as
  -- commenting out until the end of the file is a common habit.)
  -- -- setLastPos lexPos
  -- Without it, we get much more useful error locations.
  String -> Parser ()
setPrevToken String
"<EOF>"
  Token -> Parser Token
forall (m :: * -> *) a. Monad m => a -> m a
return (Token -> Parser Token) -> Token -> Parser Token
forall a b. (a -> b) -> a -> b
$ Interval -> Token
TokEOF (Interval -> Token) -> Interval -> Token
forall a b. (a -> b) -> a -> b
$ SrcFile -> PositionWithoutFile -> PositionWithoutFile -> Interval
forall a.
a -> PositionWithoutFile -> PositionWithoutFile -> Interval' a
posToInterval SrcFile
lexSrcFile PositionWithoutFile
lexPos PositionWithoutFile
lexPos

-- | Set the current input and lex a new token (calls 'lexToken').
skipTo :: AlexInput -> Parser Token
skipTo :: AlexInput -> Parser Token
skipTo AlexInput
inp = do
  AlexInput -> Parser ()
setLexInput AlexInput
inp
  Parser Token
lexToken

{-| Scan the input to find the next token. Calls
'Agda.Syntax.Parser.Lexer.alexScanUser'. This is the main lexing function
where all the work happens. The function 'Agda.Syntax.Parser.Lexer.lexer',
used by the parser is the continuation version of this function.
-}
lexToken :: Parser Token
lexToken :: Parser Token
lexToken =
    do  AlexInput
inp <- Parser AlexInput
getLexInput
        [LexState]
lss <- Parser [LexState]
getLexState
        ParseFlags
flags <- Parser ParseFlags
getParseFlags
        case ([LexState], ParseFlags)
-> AlexInput -> LexState -> AlexReturn (LexAction Token)
alexScanUser ([LexState]
lss, ParseFlags
flags) AlexInput
inp (LexState -> [LexState] -> LexState
forall a. a -> [a] -> a
headWithDefault LexState
forall a. HasCallStack => a
__IMPOSSIBLE__ [LexState]
lss) of
            AlexReturn (LexAction Token)
AlexEOF                     -> AlexInput -> Parser Token
returnEOF AlexInput
inp
            AlexSkip AlexInput
inp' LexState
len           -> AlexInput -> Parser Token
skipTo AlexInput
inp'
            AlexToken AlexInput
inp' LexState
len LexAction Token
action   -> Token -> Token
postToken (Token -> Token) -> Parser Token -> Parser Token
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> LexAction Token
-> AlexInput -> AlexInput -> LexState -> Parser Token
forall r.
LexAction r -> AlexInput -> AlexInput -> LexState -> Parser r
runLexAction LexAction Token
action AlexInput
inp AlexInput
inp' LexState
len
            AlexError AlexInput
i                 -> String -> Parser Token
forall a. String -> Parser a
parseError (String -> Parser Token) -> String -> Parser Token
forall a b. (a -> b) -> a -> b
$ [String] -> String
forall (t :: * -> *) a. Foldable t => t [a] -> [a]
concat
              [ String
"Lexical error"
              , case String -> Maybe Char
forall a. [a] -> Maybe a
listToMaybe (String -> Maybe Char) -> String -> Maybe Char
forall a b. (a -> b) -> a -> b
$ AlexInput -> String
lexInput AlexInput
i of
                  Just Char
'\t'                -> String
" (you may want to replace tabs with spaces)"
                  Just Char
c | Bool -> Bool
not (Char -> Bool
isPrint Char
c) -> String
" (unprintable character)"
                  Maybe Char
_ -> String
""
              , String
":"
              ]

isSub :: Char -> Bool
isSub :: Char -> Bool
isSub Char
c = Char
'\x2080' Char -> Char -> Bool
forall a. Ord a => a -> a -> Bool
<= Char
c Bool -> Bool -> Bool
&& Char
c Char -> Char -> Bool
forall a. Ord a => a -> a -> Bool
<= Char
'\x2089'

readSubscript :: [Char] -> Integer
readSubscript :: String -> Integer
readSubscript = String -> Integer
forall a. Read a => String -> a
read (String -> Integer) -> (String -> String) -> String -> Integer
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (Char -> Char) -> String -> String
forall a b. (a -> b) -> [a] -> [b]
map (\Char
c -> LexState -> Char
forall a. Enum a => LexState -> a
toEnum (Char -> LexState
forall a. Enum a => a -> LexState
fromEnum Char
c LexState -> LexState -> LexState
forall a. Num a => a -> a -> a
- LexState
0x2080 LexState -> LexState -> LexState
forall a. Num a => a -> a -> a
+ Char -> LexState
forall a. Enum a => a -> LexState
fromEnum Char
'0'))

postToken :: Token -> Token
postToken :: Token -> Token
postToken (TokId (Interval
r, String
"\x03bb")) = Symbol -> Interval -> Token
TokSymbol Symbol
SymLambda Interval
r
postToken (TokId (Interval
r, String
"\x2026")) = Symbol -> Interval -> Token
TokSymbol Symbol
SymEllipsis Interval
r
postToken (TokId (Interval
r, String
"\x2192")) = Symbol -> Interval -> Token
TokSymbol Symbol
SymArrow Interval
r
postToken (TokId (Interval
r, String
"\x2983")) = Symbol -> Interval -> Token
TokSymbol Symbol
SymDoubleOpenBrace Interval
r
postToken (TokId (Interval
r, String
"\x2984")) = Symbol -> Interval -> Token
TokSymbol Symbol
SymDoubleCloseBrace Interval
r
postToken (TokId (Interval
r, String
"\x2987")) = Symbol -> Interval -> Token
TokSymbol Symbol
SymOpenIdiomBracket Interval
r
postToken (TokId (Interval
r, String
"\x2988")) = Symbol -> Interval -> Token
TokSymbol Symbol
SymCloseIdiomBracket Interval
r
postToken (TokId (Interval
r, String
"\x2987\x2988")) = Symbol -> Interval -> Token
TokSymbol Symbol
SymEmptyIdiomBracket Interval
r
postToken (TokId (Interval
r, String
"\x2200")) = Keyword -> Interval -> Token
TokKeyword Keyword
KwForall Interval
r
postToken Token
t = Token
t

{--------------------------------------------------------------------------
    Lex actions
 --------------------------------------------------------------------------}

-- | The most general way of parsing a token.
token :: (String -> Parser tok) -> LexAction tok
token :: forall tok. (String -> Parser tok) -> LexAction tok
token String -> Parser tok
action = (AlexInput -> AlexInput -> LexState -> Parser tok) -> LexAction tok
forall r.
(AlexInput -> AlexInput -> LexState -> Parser r) -> LexAction r
LexAction ((AlexInput -> AlexInput -> LexState -> Parser tok)
 -> LexAction tok)
-> (AlexInput -> AlexInput -> LexState -> Parser tok)
-> LexAction tok
forall a b. (a -> b) -> a -> b
$ \ AlexInput
inp AlexInput
inp' LexState
len ->
    do  AlexInput -> Parser ()
setLexInput AlexInput
inp'
        let t :: String
t = LexState -> String -> String
forall a. LexState -> [a] -> [a]
take LexState
len (String -> String) -> String -> String
forall a b. (a -> b) -> a -> b
$ AlexInput -> String
lexInput AlexInput
inp
        String -> Parser ()
setPrevToken String
t
        PositionWithoutFile -> Parser ()
setLastPos (PositionWithoutFile -> Parser ())
-> PositionWithoutFile -> Parser ()
forall a b. (a -> b) -> a -> b
$ AlexInput -> PositionWithoutFile
lexPos AlexInput
inp
        String -> Parser tok
action String
t

-- | Parse a token from an 'Interval' and the lexed string.
withInterval :: ((Interval, String) -> tok) -> LexAction tok
withInterval :: forall tok. ((Interval, String) -> tok) -> LexAction tok
withInterval (Interval, String) -> tok
f = (String -> Parser tok) -> LexAction tok
forall tok. (String -> Parser tok) -> LexAction tok
token ((String -> Parser tok) -> LexAction tok)
-> (String -> Parser tok) -> LexAction tok
forall a b. (a -> b) -> a -> b
$ \String
s -> do
                   Interval
r <- Parser Interval
getParseInterval
                   tok -> Parser tok
forall (m :: * -> *) a. Monad m => a -> m a
return (tok -> Parser tok) -> tok -> Parser tok
forall a b. (a -> b) -> a -> b
$ (Interval, String) -> tok
f (Interval
r,String
s)

-- | Like 'withInterval', but applies a function to the string.
withInterval' :: (String -> a) -> ((Interval, a) -> tok) -> LexAction tok
withInterval' :: forall a tok.
(String -> a) -> ((Interval, a) -> tok) -> LexAction tok
withInterval' String -> a
f (Interval, a) -> tok
t = ((Interval, String) -> tok) -> LexAction tok
forall tok. ((Interval, String) -> tok) -> LexAction tok
withInterval ((Interval, a) -> tok
t ((Interval, a) -> tok)
-> ((Interval, String) -> (Interval, a))
-> (Interval, String)
-> tok
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (String -> a) -> (Interval, String) -> (Interval, a)
forall (p :: * -> * -> *) b c a.
Bifunctor p =>
(b -> c) -> p a b -> p a c
second String -> a
f)

-- | Return a token without looking at the lexed string.
withInterval_ :: (Interval -> r) -> LexAction r
withInterval_ :: forall r. (Interval -> r) -> LexAction r
withInterval_ Interval -> r
f = ((Interval, String) -> r) -> LexAction r
forall tok. ((Interval, String) -> tok) -> LexAction tok
withInterval (Interval -> r
f (Interval -> r)
-> ((Interval, String) -> Interval) -> (Interval, String) -> r
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (Interval, String) -> Interval
forall a b. (a, b) -> a
fst)


-- | Executed for layout keywords. Enters the 'Agda.Syntax.Parser.Lexer.layout'
--   state and performs the given action.
withLayout :: Keyword -> LexAction r -> LexAction r
withLayout :: forall r. Keyword -> LexAction r -> LexAction r
withLayout Keyword
kw LexAction r
a = LexState -> Parser ()
pushLexState LexState
layout Parser () -> LexAction r -> LexAction r
forall r. Parser () -> LexAction r -> LexAction r
`andThen` Parser ()
setLayoutKw Parser () -> LexAction r -> LexAction r
forall r. Parser () -> LexAction r -> LexAction r
`andThen` LexAction r
a
  where
  setLayoutKw :: Parser ()
setLayoutKw = (ParseState -> ParseState) -> Parser ()
forall s (m :: * -> *). MonadState s m => (s -> s) -> m ()
modify ((ParseState -> ParseState) -> Parser ())
-> (ParseState -> ParseState) -> Parser ()
forall a b. (a -> b) -> a -> b
$ \ ParseState
st -> ParseState
st { parseLayKw :: Keyword
parseLayKw = Keyword
kw }

infixr 1 `andThen`

-- | Prepend some parser manipulation to an action.
andThen :: Parser () -> LexAction r -> LexAction r
andThen :: forall r. Parser () -> LexAction r -> LexAction r
andThen Parser ()
cmd LexAction r
a = (AlexInput -> AlexInput -> LexState -> Parser r) -> LexAction r
forall r.
(AlexInput -> AlexInput -> LexState -> Parser r) -> LexAction r
LexAction ((AlexInput -> AlexInput -> LexState -> Parser r) -> LexAction r)
-> (AlexInput -> AlexInput -> LexState -> Parser r) -> LexAction r
forall a b. (a -> b) -> a -> b
$ \ AlexInput
inp AlexInput
inp' LexState
n -> do
  Parser ()
cmd
  LexAction r -> AlexInput -> AlexInput -> LexState -> Parser r
forall r.
LexAction r -> AlexInput -> AlexInput -> LexState -> Parser r
runLexAction LexAction r
a AlexInput
inp AlexInput
inp' LexState
n

-- | Visit the current lexeme again.
revisit :: LexAction Token
revisit :: LexAction Token
revisit = (AlexInput -> AlexInput -> LexState -> Parser Token)
-> LexAction Token
forall r.
(AlexInput -> AlexInput -> LexState -> Parser r) -> LexAction r
LexAction ((AlexInput -> AlexInput -> LexState -> Parser Token)
 -> LexAction Token)
-> (AlexInput -> AlexInput -> LexState -> Parser Token)
-> LexAction Token
forall a b. (a -> b) -> a -> b
$ \ AlexInput
_ AlexInput
_ LexState
_ -> Parser Token
lexToken

-- | Throw away the current lexeme.
skip :: LexAction Token
skip :: LexAction Token
skip = (AlexInput -> AlexInput -> LexState -> Parser Token)
-> LexAction Token
forall r.
(AlexInput -> AlexInput -> LexState -> Parser r) -> LexAction r
LexAction ((AlexInput -> AlexInput -> LexState -> Parser Token)
 -> LexAction Token)
-> (AlexInput -> AlexInput -> LexState -> Parser Token)
-> LexAction Token
forall a b. (a -> b) -> a -> b
$ \ AlexInput
_ AlexInput
inp' LexState
_ -> AlexInput -> Parser Token
skipTo AlexInput
inp'

-- | Enter a new state without consuming any input.
begin :: LexState -> LexAction Token
begin :: LexState -> LexAction Token
begin LexState
code = LexState -> LexAction Token -> LexAction Token
forall a. LexState -> LexAction a -> LexAction a
beginWith LexState
code LexAction Token
revisit

-- | Exit the current state without consuming any input.
end :: LexAction Token
end :: LexAction Token
end = LexAction Token -> LexAction Token
forall a. LexAction a -> LexAction a
endWith LexAction Token
revisit

-- | Enter a new state throwing away the current lexeme.
begin_ :: LexState -> LexAction Token
begin_ :: LexState -> LexAction Token
begin_ LexState
code = LexState -> LexAction Token -> LexAction Token
forall a. LexState -> LexAction a -> LexAction a
beginWith LexState
code LexAction Token
skip

-- | Exit the current state throwing away the current lexeme.
end_ :: LexAction Token
end_ :: LexAction Token
end_ = LexAction Token -> LexAction Token
forall a. LexAction a -> LexAction a
endWith LexAction Token
skip

-- | Enter a new state and perform the given action.
beginWith :: LexState -> LexAction a -> LexAction a
beginWith :: forall a. LexState -> LexAction a -> LexAction a
beginWith LexState
code LexAction a
a = LexState -> Parser ()
pushLexState LexState
code Parser () -> LexAction a -> LexAction a
forall r. Parser () -> LexAction r -> LexAction r
`andThen` LexAction a
a

-- | Exit the current state and perform the given action.
endWith :: LexAction a -> LexAction a
endWith :: forall a. LexAction a -> LexAction a
endWith LexAction a
a = Parser ()
popLexState Parser () -> LexAction a -> LexAction a
forall r. Parser () -> LexAction r -> LexAction r
`andThen` LexAction a
a


-- | Parse a 'Keyword' token, triggers layout for 'layoutKeywords'.
keyword :: Keyword -> LexAction Token
keyword :: Keyword -> LexAction Token
keyword Keyword
k =
    case Keyword
k of

        -- Unconditional layout keyword.
        Keyword
_ | Keyword
k Keyword -> [Keyword] -> Bool
forall (t :: * -> *) a. (Foldable t, Eq a) => a -> t a -> Bool
`elem` [Keyword]
layoutKeywords ->
            Keyword -> LexAction Token -> LexAction Token
forall r. Keyword -> LexAction r -> LexAction r
withLayout Keyword
k LexAction Token
cont

        -- Andreas, 2021-05-06, issue #5356:
        -- @constructor@ is not a layout keyword after all, replaced by @data _ where@.
        -- -- @constructor@ is not a layout keyword in @record ... where@ blocks,
        -- -- only in @interleaved mutual@ blocks.
        -- KwConstructor -> do
        --     cxt <- getContext
        --     if inMutualAndNotInWhereBlock cxt
        --       then withLayout k cont
        --       else cont

        Keyword
_ -> LexAction Token
cont
    where
    cont :: LexAction Token
cont = (Interval -> Token) -> LexAction Token
forall r. (Interval -> r) -> LexAction r
withInterval_ (Keyword -> Interval -> Token
TokKeyword Keyword
k)

    -- Andreas, 2021-05-06, issue #5356:
    -- @constructor@ is not a layout keyword after all, replaced by @data _ where@.
    -- -- Most recent block decides ...
    -- inMutualAndNotInWhereBlock = \case
    --   Layout KwMutual _ _ : _ -> True
    --   Layout KwWhere  _ _ : _ -> False
    --   _ : bs                  -> inMutualAndNotInWhereBlock bs
    --   []                      -> True  -- For better errors on stray @constructor@ decls.


-- | Parse a 'Symbol' token.
symbol :: Symbol -> LexAction Token
symbol :: Symbol -> LexAction Token
symbol Symbol
s = (Interval -> Token) -> LexAction Token
forall r. (Interval -> r) -> LexAction r
withInterval_ (Symbol -> Interval -> Token
TokSymbol Symbol
s)


-- | Parse a number.

number :: String -> Integer
number :: String -> Integer
number String
str = case String
str of
    Char
'0' : Char
'x' : String
num -> Integer -> String -> Integer
parseNumber Integer
16 String
num
    Char
'0' : Char
'b' : String
num -> Integer -> String -> Integer
parseNumber Integer
2  String
num
    String
num             -> Integer -> String -> Integer
parseNumber Integer
10 String
num
    where
        parseNumber :: Integer -> String -> Integer
        parseNumber :: Integer -> String -> Integer
parseNumber Integer
radix = (Integer -> Char -> Integer) -> Integer -> String -> Integer
forall (t :: * -> *) b a.
Foldable t =>
(b -> a -> b) -> b -> t a -> b
foldl' (Integer -> Integer -> Char -> Integer
addDigit Integer
radix) Integer
0

        -- We rely on Agda.Syntax.Parser.Lexer to enforce that the digits are
        -- in the correct range (so e.g. the digit 'E' cannot appear in a
        -- binary number).
        addDigit :: Integer -> Integer -> Char -> Integer
        addDigit :: Integer -> Integer -> Char -> Integer
addDigit Integer
radix Integer
n Char
'_' = Integer
n
        addDigit Integer
radix Integer
n Char
c   = Integer
n Integer -> Integer -> Integer
forall a. Num a => a -> a -> a
* Integer
radix Integer -> Integer -> Integer
forall a. Num a => a -> a -> a
+ LexState -> Integer
forall a b. (Integral a, Num b) => a -> b
fromIntegral (Char -> LexState
digitToInt Char
c)

integer :: String -> Integer
integer :: String -> Integer
integer = \case
  Char
'-' : String
str -> - (String -> Integer
number String
str)
  String
str       -> String -> Integer
number String
str

-- | Parse a literal.
literal' :: (String -> a) -> (a -> Literal) -> LexAction Token
literal' :: forall a. (String -> a) -> (a -> Literal) -> LexAction Token
literal' String -> a
read a -> Literal
lit = (String -> a) -> ((Interval, a) -> Token) -> LexAction Token
forall a tok.
(String -> a) -> ((Interval, a) -> tok) -> LexAction tok
withInterval' String -> a
read (((Interval, a) -> Token) -> LexAction Token)
-> ((Interval, a) -> Token) -> LexAction Token
forall a b. (a -> b) -> a -> b
$ \ (Interval
r, a
a) ->
  RLiteral -> Token
TokLiteral (RLiteral -> Token) -> RLiteral -> Token
forall a b. (a -> b) -> a -> b
$ Range -> Literal -> RLiteral
forall a. Range -> a -> Ranged a
Ranged (Interval -> Range
forall a. HasRange a => a -> Range
getRange Interval
r) (Literal -> RLiteral) -> Literal -> RLiteral
forall a b. (a -> b) -> a -> b
$ a -> Literal
lit a
a

literal :: Read a => (a -> Literal) -> LexAction Token
literal :: forall a. Read a => (a -> Literal) -> LexAction Token
literal = (String -> a) -> (a -> Literal) -> LexAction Token
forall a. (String -> a) -> (a -> Literal) -> LexAction Token
literal' String -> a
forall a. Read a => String -> a
read

-- | Parse an identifier. Identifiers can be qualified (see 'Name').
--   Example: @Foo.Bar.f@
identifier :: LexAction Token
identifier :: LexAction Token
identifier = (Either (Interval, String) [(Interval, String)] -> Token)
-> LexAction Token
forall a.
(Either (Interval, String) [(Interval, String)] -> a)
-> LexAction a
qualified (((Interval, String) -> Token)
-> ([(Interval, String)] -> Token)
-> Either (Interval, String) [(Interval, String)]
-> Token
forall a c b. (a -> c) -> (b -> c) -> Either a b -> c
either (Interval, String) -> Token
TokId [(Interval, String)] -> Token
TokQId)


-- | Parse a possibly qualified name.
qualified :: (Either (Interval, String) [(Interval, String)] -> a) -> LexAction a
qualified :: forall a.
(Either (Interval, String) [(Interval, String)] -> a)
-> LexAction a
qualified Either (Interval, String) [(Interval, String)] -> a
tok =
    (String -> Parser a) -> LexAction a
forall tok. (String -> Parser tok) -> LexAction tok
token ((String -> Parser a) -> LexAction a)
-> (String -> Parser a) -> LexAction a
forall a b. (a -> b) -> a -> b
$ \String
s ->
    do  Interval
i <- Parser Interval
getParseInterval
        case Interval -> [String] -> [(Interval, String)]
mkName Interval
i ([String] -> [(Interval, String)])
-> [String] -> [(Interval, String)]
forall a b. (a -> b) -> a -> b
$ (Char -> Bool) -> String -> [String]
forall a. (a -> Bool) -> [a] -> [[a]]
wordsBy (Char -> Char -> Bool
forall a. Eq a => a -> a -> Bool
==Char
'.') String
s of
            []  -> String -> Parser a
forall a. String -> Parser a
lexError String
"lex error on .."
            [(Interval, String)
x] -> a -> Parser a
forall (m :: * -> *) a. Monad m => a -> m a
return (a -> Parser a) -> a -> Parser a
forall a b. (a -> b) -> a -> b
$ Either (Interval, String) [(Interval, String)] -> a
tok (Either (Interval, String) [(Interval, String)] -> a)
-> Either (Interval, String) [(Interval, String)] -> a
forall a b. (a -> b) -> a -> b
$ (Interval, String)
-> Either (Interval, String) [(Interval, String)]
forall a b. a -> Either a b
Left  (Interval, String)
x
            [(Interval, String)]
xs  -> a -> Parser a
forall (m :: * -> *) a. Monad m => a -> m a
return (a -> Parser a) -> a -> Parser a
forall a b. (a -> b) -> a -> b
$ Either (Interval, String) [(Interval, String)] -> a
tok (Either (Interval, String) [(Interval, String)] -> a)
-> Either (Interval, String) [(Interval, String)] -> a
forall a b. (a -> b) -> a -> b
$ [(Interval, String)]
-> Either (Interval, String) [(Interval, String)]
forall a b. b -> Either a b
Right [(Interval, String)]
xs
    where
        -- Compute the ranges for the substrings (separated by '.') of
        -- a name. Dots are included: the intervals generated for
        -- "A.B.x" correspond to "A.", "B." and "x".
        mkName :: Interval -> [String] -> [(Interval, String)]
        mkName :: Interval -> [String] -> [(Interval, String)]
mkName Interval
_ []     = []
        mkName Interval
i [String
x]    = [(Interval
i, String
x)]
        mkName Interval
i (String
x:[String]
xs) = (Interval
i0, String
x) (Interval, String) -> [(Interval, String)] -> [(Interval, String)]
forall a. a -> [a] -> [a]
: Interval -> [String] -> [(Interval, String)]
mkName Interval
i1 [String]
xs
            where
                p0 :: Position' SrcFile
p0 = Interval -> Position' SrcFile
forall a. Interval' a -> Position' a
iStart Interval
i
                p1 :: Position' SrcFile
p1 = Interval -> Position' SrcFile
forall a. Interval' a -> Position' a
iEnd Interval
i
                p' :: Position' SrcFile
p' = Position' SrcFile -> Char -> Position' SrcFile
forall a. Position' a -> Char -> Position' a
movePos (Position' SrcFile -> String -> Position' SrcFile
forall a. Position' a -> String -> Position' a
movePosByString Position' SrcFile
p0 String
x) Char
'.'
                i0 :: Interval
i0 = Position' SrcFile -> Position' SrcFile -> Interval
forall a. Position' a -> Position' a -> Interval' a
Interval Position' SrcFile
p0 Position' SrcFile
p'
                i1 :: Interval
i1 = Position' SrcFile -> Position' SrcFile -> Interval
forall a. Position' a -> Position' a -> Interval' a
Interval Position' SrcFile
p' Position' SrcFile
p1


{--------------------------------------------------------------------------
    Predicates
 --------------------------------------------------------------------------}

-- | True when the given character is the next character of the input string.
followedBy :: Char -> LexPredicate
followedBy :: Char -> LexPredicate
followedBy Char
c' ([LexState], ParseFlags)
_ AlexInput
_ LexState
_ AlexInput
inp =
    case AlexInput -> String
lexInput AlexInput
inp of
        []  -> Bool
False
        Char
c:String
_ -> Char
c Char -> Char -> Bool
forall a. Eq a => a -> a -> Bool
== Char
c'

-- | True if we are at the end of the file.
eof :: LexPredicate
eof :: LexPredicate
eof ([LexState], ParseFlags)
_ AlexInput
_ LexState
_ AlexInput
inp = String -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null (String -> Bool) -> String -> Bool
forall a b. (a -> b) -> a -> b
$ AlexInput -> String
lexInput AlexInput
inp

-- | True if the given state appears somewhere on the state stack
inState :: LexState -> LexPredicate
inState :: LexState -> LexPredicate
inState LexState
s ([LexState]
ls, ParseFlags
_) AlexInput
_ LexState
_ AlexInput
_ = LexState
s LexState -> [LexState] -> Bool
forall (t :: * -> *) a. (Foldable t, Eq a) => a -> t a -> Bool
`elem` [LexState]
ls