Text.Pandoc.Parsing: remove `nested` [API change].

It was not being used, and in fact it was a bad idea from
the beginning, as it had no hope of solving the problem
it was introduced to solve.

7 files changed, 12 insertions, 69 deletions

diff --git a/src/Text/Pandoc/Parsing.hs b/src/Text/Pandoc/Parsing.hs
index 501e8c74b..6284bb0f3 100644
--- a/src/Text/Pandoc/Parsing.hs
+++ b/src/Text/Pandoc/Parsing.hs
@@ -105,7 +105,6 @@ module Text.Pandoc.Parsing ( module Text.Pandoc.Sources,
                              doubleCloseQuote,
                              ellipses,
                              dash,
-                             nested,
                              citeKey,
                              Parsec,
                              ParsecT,
@@ -279,7 +278,6 @@ import Text.Pandoc.Parsing.General
       manyTillChar,
       manyUntil,
       manyUntilChar,
-      nested,
       nonspaceChar,
       notFollowedBy',
       oneOfStrings,
diff --git a/src/Text/Pandoc/Parsing/General.hs b/src/Text/Pandoc/Parsing/General.hs
index f09175cd4..397a3e94f 100644
--- a/src/Text/Pandoc/Parsing/General.hs
+++ b/src/Text/Pandoc/Parsing/General.hs
@@ -37,7 +37,6 @@ module Text.Pandoc.Parsing.General
   , manyTillChar
   , manyUntil
   , manyUntilChar
-  , nested
   , nonspaceChar
   , notFollowedBy'
   , oneOfStrings
@@ -63,8 +62,7 @@ module Text.Pandoc.Parsing.General
 where
 
 import Control.Monad
-  ( guard
-  , join
+  ( join
   , liftM
   , unless
   , void
@@ -683,19 +681,6 @@ registerHeader (ident,classes,kvs) header' = do
           updateState $ updateIdentifierList $ Set.insert ident
         return (ident,classes,kvs)
 
--- This is used to prevent exponential blowups for things like:
--- a**a*a**a*a**a*a**a*a**a*a**a*a**
-nested :: Stream s m a
-       => ParsecT s ParserState m a
-       -> ParsecT s ParserState m a
-nested p = do
-  nestlevel <- stateMaxNestingLevel <$>  getState
-  guard $ nestlevel > 0
-  updateState $ \st -> st{ stateMaxNestingLevel = stateMaxNestingLevel st - 1 }
-  res <- p
-  updateState $ \st -> st{ stateMaxNestingLevel = nestlevel }
-  return res
-
 token :: (Stream s m t)
       => (t -> Text)
       -> (t -> SourcePos)
diff --git a/src/Text/Pandoc/Parsing/State.hs b/src/Text/Pandoc/Parsing/State.hs
index 1efb90b73..66432fa1e 100644
--- a/src/Text/Pandoc/Parsing/State.hs
+++ b/src/Text/Pandoc/Parsing/State.hs
@@ -46,7 +46,6 @@ data ParserState = ParserState
   , stateQuoteContext    :: QuoteContext  -- ^ Inside quoted environment?
   , stateAllowLinks      :: Bool          -- ^ Allow parsing of links
   , stateAllowLineBreaks :: Bool          -- ^ Allow parsing of line breaks
-  , stateMaxNestingLevel :: Int           -- ^ Max # of nested Strong/Emph
   , stateLastStrPos      :: Maybe SourcePos -- ^ Position after last str parsed
   , stateKeys            :: KeyTable      -- ^ List of reference keys
   , stateHeaderKeys      :: KeyTable      -- ^ List of implicit header ref keys
@@ -141,7 +140,6 @@ defaultParserState = ParserState
   , stateQuoteContext    = NoQuote
   , stateAllowLinks      = True
   , stateAllowLineBreaks = True
-  , stateMaxNestingLevel = 6
   , stateLastStrPos      = Nothing
   , stateKeys            = M.empty
   , stateHeaderKeys      = M.empty
diff --git a/src/Text/Pandoc/Readers/DokuWiki.hs b/src/Text/Pandoc/Readers/DokuWiki.hs
index d62ea970f..3d52cd747 100644
--- a/src/Text/Pandoc/Readers/DokuWiki.hs
+++ b/src/Text/Pandoc/Readers/DokuWiki.hs
@@ -27,7 +27,7 @@ import qualified Text.Pandoc.Builder as B
 import Text.Pandoc.Class.PandocMonad (PandocMonad (..))
 import Text.Pandoc.Definition
 import Text.Pandoc.Options
-import Text.Pandoc.Parsing hiding (enclosed, nested)
+import Text.Pandoc.Parsing hiding (enclosed)
 import Text.Pandoc.Shared (trim, stringify, tshow)
 import Data.List (isPrefixOf, isSuffixOf)
 import qualified Safe
@@ -53,15 +53,6 @@ type DWParser = ParsecT Sources ParserState
 eol :: (Stream s m Char, UpdateSourcePos s Char) => ParsecT s st m ()
 eol = void newline <|> eof
 
-nested :: PandocMonad m => DWParser m a -> DWParser m a
-nested p = do
-  nestlevel <- stateMaxNestingLevel <$>  getState
-  guard $ nestlevel > 0
-  updateState $ \st -> st{ stateMaxNestingLevel = stateMaxNestingLevel st - 1 }
-  res <- p
-  updateState $ \st -> st{ stateMaxNestingLevel = nestlevel }
-  return res
-
 guardColumnOne :: PandocMonad m => DWParser m ()
 guardColumnOne = getPosition >>= \pos -> guard (sourceColumn pos == 1)
 
@@ -163,7 +154,7 @@ nestedInlines :: (Show a, PandocMonad m)
 nestedInlines end = innerSpace <|> nestedInline
   where
     innerSpace   = try $ whitespace <* notFollowedBy end
-    nestedInline = notFollowedBy whitespace >> nested inline
+    nestedInline = notFollowedBy whitespace >> inline
 
 bold :: PandocMonad m => DWParser m B.Inlines
 bold = try $ B.strong <$> enclosed (string "**") nestedInlines
diff --git a/src/Text/Pandoc/Readers/MediaWiki.hs b/src/Text/Pandoc/Readers/MediaWiki.hs
index 33fcace2a..e7fae679c 100644
--- a/src/Text/Pandoc/Readers/MediaWiki.hs
+++ b/src/Text/Pandoc/Readers/MediaWiki.hs
@@ -34,7 +34,7 @@ import Text.Pandoc.Class.PandocMonad (PandocMonad (..))
 import Text.Pandoc.Definition
 import Text.Pandoc.Logging
 import Text.Pandoc.Options
-import Text.Pandoc.Parsing hiding (nested, tableCaption)
+import Text.Pandoc.Parsing hiding (tableCaption)
 import Text.Pandoc.Readers.HTML (htmlTag, isBlockTag, isCommentTag, toAttr)
 import Text.Pandoc.Shared (safeRead, stringify, stripTrailingNewlines,
                            trim, splitTextBy, tshow, formatCode)
@@ -86,17 +86,6 @@ instance HasLogMessages MWState where
 -- auxiliary functions
 --
 
--- This is used to prevent exponential blowups for things like:
--- ''a'''a''a'''a''a'''a''a'''a
-nested :: PandocMonad m => MWParser m a -> MWParser m a
-nested p = do
-  nestlevel <- mwMaxNestingLevel `fmap` getState
-  guard $ nestlevel > 0
-  updateState $ \st -> st{ mwMaxNestingLevel = mwMaxNestingLevel st - 1 }
-  res <- p
-  updateState $ \st -> st{ mwMaxNestingLevel = nestlevel }
-  return res
-
 specialChars :: [Char]
 specialChars = "'[]<=&*{}|\":\\"
 
@@ -706,12 +695,12 @@ inlinesBetween start end =
   trimInlines . mconcat <$> try (start >> many1Till inline end)
 
 emph :: PandocMonad m => MWParser m Inlines
-emph = B.emph <$> nested (inlinesBetween start end)
+emph = B.emph <$> inlinesBetween start end
     where start = sym "''"
           end   = try $ notFollowedBy' (() <$ strong) >> sym "''"
 
 strong :: PandocMonad m => MWParser m Inlines
-strong = B.strong <$> nested (inlinesBetween start end)
+strong = B.strong <$> inlinesBetween start end
     where start = sym "'''"
           end   = sym "'''"
 
@@ -720,6 +709,6 @@ doubleQuotes = do
   guardEnabled Ext_smart
   inTT <- mwInTT <$> getState
   guard (not inTT)
-  B.doubleQuoted <$> nested (inlinesBetween openDoubleQuote closeDoubleQuote)
+  B.doubleQuoted <$> inlinesBetween openDoubleQuote closeDoubleQuote
     where openDoubleQuote = sym "\"" >> lookAhead nonspaceChar
           closeDoubleQuote = try $ sym "\""
diff --git a/src/Text/Pandoc/Readers/TWiki.hs b/src/Text/Pandoc/Readers/TWiki.hs
index 54b69c34f..8bba600a2 100644
--- a/src/Text/Pandoc/Readers/TWiki.hs
+++ b/src/Text/Pandoc/Readers/TWiki.hs
@@ -26,7 +26,7 @@ import qualified Text.Pandoc.Builder as B
 import Text.Pandoc.Class.PandocMonad (PandocMonad (..))
 import Text.Pandoc.Definition
 import Text.Pandoc.Options
-import Text.Pandoc.Parsing hiding (enclosed, nested)
+import Text.Pandoc.Parsing hiding (enclosed)
 import Text.Pandoc.Readers.HTML (htmlTag, isCommentTag)
 import Text.Pandoc.Shared (tshow)
 import Text.Pandoc.XML (fromEntities)
@@ -52,15 +52,6 @@ type TWParser = ParsecT Sources ParserState
 tryMsg :: Text -> TWParser m a -> TWParser m a
 tryMsg msg p = try p <?> T.unpack msg
 
-nested :: PandocMonad m => TWParser m a -> TWParser m a
-nested p = do
-  nestlevel <- stateMaxNestingLevel <$>  getState
-  guard $ nestlevel > 0
-  updateState $ \st -> st{ stateMaxNestingLevel = stateMaxNestingLevel st - 1 }
-  res <- p
-  updateState $ \st -> st{ stateMaxNestingLevel = nestlevel }
-  return res
-
 htmlElement :: PandocMonad m => Text -> TWParser m (Attr, Text)
 htmlElement tag = tryMsg tag $ do
   (TagOpen _ attr, _) <- htmlTag (~== TagOpen tag [])
@@ -85,7 +76,7 @@ parseHtmlContentWithAttrs tag parser = do
   parsedContent <- try $ parseContent content
   return (attr, parsedContent)
   where
-    parseContent = parseFromString' $ nested $ manyTill parser endOfContent
+    parseContent = parseFromString' $ manyTill parser endOfContent
     endOfContent = try $ skipMany blankline >> skipSpaces >> eof
 
 parseCharHtmlContentWithAttrs :: PandocMonad m
@@ -402,7 +393,7 @@ nestedInlines :: (Show a, PandocMonad m)
 nestedInlines end = innerSpace <|> nestedInline
   where
     innerSpace   = try $ whitespace <* notFollowedBy end
-    nestedInline = notFollowedBy whitespace >> nested inline
+    nestedInline = notFollowedBy whitespace >> inline
 
 strong :: PandocMonad m => TWParser m B.Inlines
 strong = try $ B.strong <$> enclosed (char '*') nestedInlines
diff --git a/src/Text/Pandoc/Readers/TikiWiki.hs b/src/Text/Pandoc/Readers/TikiWiki.hs
index 10714ca9f..f009fad61 100644
--- a/src/Text/Pandoc/Readers/TikiWiki.hs
+++ b/src/Text/Pandoc/Readers/TikiWiki.hs
@@ -29,7 +29,7 @@ import Text.Pandoc.Class.PandocMonad (PandocMonad (..))
 import Text.Pandoc.Definition
 import Text.Pandoc.Logging (Verbosity (..))
 import Text.Pandoc.Options
-import Text.Pandoc.Parsing hiding (enclosed, nested)
+import Text.Pandoc.Parsing hiding (enclosed)
 import Text.Pandoc.Shared (safeRead)
 import Text.Pandoc.XML (fromEntities)
 import Text.Printf (printf)
@@ -58,15 +58,6 @@ tryMsg msg p = try p <?> T.unpack msg
 skip :: TikiWikiParser m a -> TikiWikiParser m ()
 skip parser = Control.Monad.void parser
 
-nested :: PandocMonad m => TikiWikiParser m a -> TikiWikiParser m a
-nested p = do
-  nestlevel <- stateMaxNestingLevel <$>  getState
-  guard $ nestlevel > 0
-  updateState $ \st -> st{ stateMaxNestingLevel = stateMaxNestingLevel st - 1 }
-  res <- p
-  updateState $ \st -> st{ stateMaxNestingLevel = nestlevel }
-  return res
-
 --
 -- main parser
 --
@@ -450,7 +441,7 @@ nestedInlines :: (Show a, PandocMonad m) => TikiWikiParser m a -> TikiWikiParser
 nestedInlines end = innerSpace <|> nestedInline
   where
     innerSpace   = try $ whitespace <* notFollowedBy end
-    nestedInline = notFollowedBy whitespace >> nested inline
+    nestedInline = notFollowedBy whitespace >> inline
 
 -- {img attId="39" imalign="right" link="http://info.tikiwiki.org" alt="Panama Hat"}
 --