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|
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE OverloadedStrings #-}
{- |
Module : Text.Pandoc.Parsing.Smart
Copyright : © 2006-2024 John MacFarlane
License : GPL-2.0-or-later
Maintainer : John MacFarlane <[email protected]>
Smart parsing of quotes, dashes, and other character combinations.
-}
module Text.Pandoc.Parsing.Smart
( apostrophe
, dash
, doubleCloseQuote
, doubleQuoteEnd
, doubleQuoteStart
, doubleQuoted
, ellipses
, singleQuoteEnd
, singleQuoteStart
, singleQuoted
, smartPunctuation
)
where
import Control.Monad (guard , void)
import Text.Pandoc.Builder (Inlines)
import Text.Pandoc.Options
( extensionEnabled
, Extension(Ext_old_dashes, Ext_smart)
, ReaderOptions(readerExtensions) )
import Text.Pandoc.Sources
import Text.Pandoc.Parsing.Capabilities
import Text.Pandoc.Parsing.General
import Text.Parsec
( (<|>)
, Stream(..)
, ParsecT
, choice
, lookAhead
, manyTill
, notFollowedBy
, try
)
import qualified Text.Pandoc.Builder as B
-- | Parses various ASCII punctuation, quotes, and apostrophe in a smart
-- way, inferring their semantic meaning.
--
-- Fails unless the 'Ext_smart' extension has been enabled.
smartPunctuation :: (HasReaderOptions st, HasLastStrPosition st,
HasQuoteContext st m,
Stream s m Char, UpdateSourcePos s Char)
=> ParsecT s st m Inlines
-> ParsecT s st m Inlines
smartPunctuation inlineParser = do
guardEnabled Ext_smart
choice [ quoted inlineParser, apostrophe, doubleCloseQuote, dash, ellipses ]
-- | Parses inline text in single or double quotes, assumes English
-- quoting conventions.
quoted :: (HasLastStrPosition st, HasQuoteContext st m,
Stream s m Char, UpdateSourcePos s Char)
=> ParsecT s st m Inlines
-> ParsecT s st m Inlines
quoted inlineParser = doubleQuoted inlineParser <|> singleQuoted inlineParser
-- | Parses inline text in single quotes, assumes English quoting
-- conventions.
singleQuoted :: (HasLastStrPosition st, HasQuoteContext st m,
Stream s m Char, UpdateSourcePos s Char)
=> ParsecT s st m Inlines
-> ParsecT s st m Inlines
singleQuoted inlineParser = do
singleQuoteStart
(B.singleQuoted . mconcat <$>
try
(withQuoteContext InSingleQuote (many1Till inlineParser singleQuoteEnd)))
<|> pure "\8217"
-- | Parses inline text in double quotes; assumes English quoting
-- conventions.
doubleQuoted :: (HasQuoteContext st m, HasLastStrPosition st,
Stream s m Char, UpdateSourcePos s Char)
=> ParsecT s st m Inlines
-> ParsecT s st m Inlines
doubleQuoted inlineParser = do
doubleQuoteStart
(B.doubleQuoted . mconcat <$>
try
(withQuoteContext InDoubleQuote (manyTill inlineParser doubleQuoteEnd)))
<|> pure (B.str "\8220")
-- | Succeeds if the parser is
--
-- * not within single quoted text;
-- * not directly after a word; and
-- * looking at an opening single quote char that's not followed by a
-- space.
--
-- Gobbles the quote character on success.
singleQuoteStart :: (HasLastStrPosition st, HasQuoteContext st m,
Stream s m Char, UpdateSourcePos s Char)
=> ParsecT s st m ()
singleQuoteStart = do
failIfInQuoteContext InSingleQuote
-- single quote start can't be right after str
guard =<< notAfterString
try $ do
char '\''
void $ lookAhead (satisfy (not . isSpaceChar))
singleQuoteEnd :: (Stream s m Char, UpdateSourcePos s Char)
=> ParsecT s st m ()
singleQuoteEnd = try $ do
char '\''
notFollowedBy alphaNum
-- | Succeeds if the parser is
--
-- * not within a double quoted text;
--
-- * not directly after a word; and
--
-- * looking at an opening double quote char that's not followed by a
-- space.
--
-- Gobbles the quote character on success.
doubleQuoteStart :: (HasLastStrPosition st,
HasQuoteContext st m,
Stream s m Char, UpdateSourcePos s Char)
=> ParsecT s st m ()
doubleQuoteStart = do
failIfInQuoteContext InDoubleQuote
guard =<< notAfterString
try $ do char '"'
void $ lookAhead (satisfy (not . isSpaceChar))
-- | Parses a closing quote character.
doubleQuoteEnd :: (Stream s m Char, UpdateSourcePos s Char)
=> ParsecT s st m ()
doubleQuoteEnd = void (char '"')
-- | Parses an ASCII apostrophe (@'@) or right single quotation mark and
-- returns a RIGHT SINGLE QUOtatiON MARK character.
apostrophe :: (Stream s m Char, UpdateSourcePos s Char)
=> ParsecT s st m Inlines
apostrophe = (char '\'' <|> char '\8217') >> return (B.str "\8217")
-- | Parses an ASCII quotation mark character and returns a RIGHT DOUBLE
-- QUOTATION MARK.
doubleCloseQuote :: (Stream s m Char, UpdateSourcePos s Char)
=> ParsecT s st m Inlines
doubleCloseQuote = B.str "\8221" <$ char '"'
-- | Parses three dots as HORIZONTAL ELLIPSIS.
ellipses :: (Stream s m Char, UpdateSourcePos s Char)
=> ParsecT s st m Inlines
ellipses = try (string "..." >> return (B.str "\8230"))
-- | Parses two hyphens as EN DASH and three as EM DASH.
--
-- If the extension @'Ext_old_dashes'@ is enabled, then two hyphens are
-- parsed as EM DASH, and one hyphen is parsed as EN DASH if it is
-- followed by a digit.
dash :: (HasReaderOptions st, Stream s m Char, UpdateSourcePos s Char)
=> ParsecT s st m Inlines
dash = try $ do
oldDashes <- extensionEnabled Ext_old_dashes <$> getOption readerExtensions
if oldDashes
then do
char '-'
(char '-' >> return (B.str "\8212"))
<|> (lookAhead digit >> return (B.str "\8211"))
else do
string "--"
(char '-' >> return (B.str "\8212"))
<|> return (B.str "\8211")
|
