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|
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE OverloadedStrings #-}
{- |
Module : Text.Pandoc.Parsing.Math
Copyright : © 2006-2022 John MacFarlane
License : GPL-2.0-or-later
Maintainer : John MacFarlane <[email protected]>
Parsing of LaTeX math.
-}
module Text.Pandoc.Parsing.Math
( mathDisplay
, mathInline
)
where
import Control.Monad (mzero, when)
import Data.Text (Text)
import Text.Parsec ((<|>), ParsecT, Stream(..), notFollowedBy, skipMany, try)
import Text.Pandoc.Options
( Extension(Ext_tex_math_dollars, Ext_tex_math_single_backslash,
Ext_tex_math_double_backslash) )
import Text.Pandoc.Parsing.Capabilities (HasReaderOptions, guardEnabled)
import Text.Pandoc.Parsing.General
import Text.Pandoc.Shared (trimMath)
import Text.Pandoc.Sources
(UpdateSourcePos, anyChar, char, digit, newline, satisfy, space, string)
import qualified Data.Text as T
mathInlineWith :: (Stream s m Char, UpdateSourcePos s Char) => Text -> Text -> ParsecT s st m Text
mathInlineWith op cl = try $ do
textStr op
when (op == "$") $ notFollowedBy space
words' <- many1Till (
(T.singleton <$>
satisfy (\c -> not (isSpaceChar c || c == '\\')))
<|> (char '\\' >>
-- This next clause is needed because \text{..} can
-- contain $, \(\), etc.
(try (string "text" >>
(("\\text" <>) <$> inBalancedBraces 0 ""))
<|> (\c -> T.pack ['\\',c]) <$> anyChar))
<|> do (blankline <* notFollowedBy' blankline) <|>
(spaceChar <* skipMany spaceChar)
notFollowedBy (char '$')
return " "
) (try $ textStr cl)
notFollowedBy digit -- to prevent capture of $5
return $ trimMath $ T.concat words'
where
inBalancedBraces :: (Stream s m Char, UpdateSourcePos s Char) => Int -> Text -> ParsecT s st m Text
inBalancedBraces n = fmap T.pack . inBalancedBraces' n . T.unpack
inBalancedBraces' :: (Stream s m Char, UpdateSourcePos s Char) => Int -> String -> ParsecT s st m String
inBalancedBraces' 0 "" = do
c <- anyChar
if c == '{'
then inBalancedBraces' 1 "{"
else mzero
inBalancedBraces' 0 s = return $ reverse s
inBalancedBraces' numOpen ('\\':xs) = do
c <- anyChar
inBalancedBraces' numOpen (c:'\\':xs)
inBalancedBraces' numOpen xs = do
c <- anyChar
case c of
'}' -> inBalancedBraces' (numOpen - 1) (c:xs)
'{' -> inBalancedBraces' (numOpen + 1) (c:xs)
_ -> inBalancedBraces' numOpen (c:xs)
mathDisplayWith :: (Stream s m Char, UpdateSourcePos s Char) => Text -> Text -> ParsecT s st m Text
mathDisplayWith op cl = try $ fmap T.pack $ do
textStr op
many1Till (satisfy (/= '\n') <|> (newline <* notFollowedBy' blankline))
(try $ textStr cl)
mathDisplay :: (HasReaderOptions st, Stream s m Char, UpdateSourcePos s Char)
=> ParsecT s st m Text
mathDisplay =
(guardEnabled Ext_tex_math_dollars >> mathDisplayWith "$$" "$$")
<|> (guardEnabled Ext_tex_math_single_backslash >>
mathDisplayWith "\\[" "\\]")
<|> (guardEnabled Ext_tex_math_double_backslash >>
mathDisplayWith "\\\\[" "\\\\]")
mathInline :: (HasReaderOptions st, Stream s m Char, UpdateSourcePos s Char)
=> ParsecT s st m Text
mathInline =
(guardEnabled Ext_tex_math_dollars >> mathInlineWith "$" "$")
<|> (guardEnabled Ext_tex_math_single_backslash >>
mathInlineWith "\\(" "\\)")
<|> (guardEnabled Ext_tex_math_double_backslash >>
mathInlineWith "\\\\(" "\\\\)")
|
