pandoc/src/Text/Pandoc/Readers/LaTeX.hs
fiddlosopher fce48c392a Specially mark code blocks that were "literate" in the input.
They can then be treated differently in the writers.  This allows
authors to distinguish bits of the literate program they are writing
from source code examples, even if the examples are marked as
Haskell for highlighting.

Resolves Issue .

git-svn-id: https://pandoc.googlecode.com/svn/trunk@1618 788f1e2b-df1e-0410-8736-df70ead52e1b
2009-11-03 06:50:17 +00:00

778 lines
24 KiB
Haskell

{-
Copyright (C) 2006-8 John MacFarlane <jgm@berkeley.edu>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-}
{- |
Module : Text.Pandoc.Readers.LaTeX
Copyright : Copyright (C) 2006-8 John MacFarlane
License : GNU GPL, version 2 or above
Maintainer : John MacFarlane <jgm@berkeley.edu>
Stability : alpha
Portability : portable
Conversion of LaTeX to 'Pandoc' document.
-}
module Text.Pandoc.Readers.LaTeX (
readLaTeX,
rawLaTeXInline,
rawLaTeXEnvironment'
) where
import Text.ParserCombinators.Parsec
import Text.Pandoc.Definition
import Text.Pandoc.Shared
import Data.Maybe ( fromMaybe )
import Data.Char ( chr )
import Data.List ( isPrefixOf, isSuffixOf )
-- | Parse LaTeX from string and return 'Pandoc' document.
readLaTeX :: ParserState -- ^ Parser state, including options for parser
-> String -- ^ String to parse (assumes @'\n'@ line endings)
-> Pandoc
readLaTeX = readWith parseLaTeX
-- characters with special meaning
specialChars :: [Char]
specialChars = "\\`$%^&_~#{}\n \t|<>'\"-"
--
-- utility functions
--
-- | Returns text between brackets and its matching pair.
bracketedText :: Char -> Char -> GenParser Char st [Char]
bracketedText openB closeB = do
result <- charsInBalanced' openB closeB
return $ [openB] ++ result ++ [closeB]
-- | Returns an option or argument of a LaTeX command.
optOrArg :: GenParser Char st [Char]
optOrArg = bracketedText '{' '}' <|> bracketedText '[' ']'
-- | True if the string begins with '{'.
isArg :: [Char] -> Bool
isArg ('{':_) = True
isArg _ = False
-- | Returns list of options and arguments of a LaTeX command.
commandArgs :: GenParser Char st [[Char]]
commandArgs = many optOrArg
-- | Parses LaTeX command, returns (name, star, list of options or arguments).
command :: GenParser Char st ([Char], [Char], [[Char]])
command = do
char '\\'
name <- many1 letter
star <- option "" (string "*") -- some commands have starred versions
args <- commandArgs
return (name, star, args)
begin :: [Char] -> GenParser Char st [Char]
begin name = try $ do
string $ "\\begin{" ++ name ++ "}"
optional commandArgs
spaces
return name
end :: [Char] -> GenParser Char st [Char]
end name = try $ do
string $ "\\end{" ++ name ++ "}"
return name
-- | Returns a list of block elements containing the contents of an
-- environment.
environment :: [Char] -> GenParser Char ParserState [Block]
environment name = try $ begin name >> spaces >> manyTill block (end name) >>~ spaces
anyEnvironment :: GenParser Char ParserState Block
anyEnvironment = try $ do
string "\\begin{"
name <- many letter
star <- option "" (string "*") -- some environments have starred variants
char '}'
optional commandArgs
spaces
contents <- manyTill block (end (name ++ star))
spaces
return $ BlockQuote contents
--
-- parsing documents
--
-- | Process LaTeX preamble, extracting metadata.
processLaTeXPreamble :: GenParser Char ParserState ()
processLaTeXPreamble = try $ manyTill
(choice [bibliographic, comment, unknownCommand, nullBlock])
(try (string "\\begin{document}")) >>
spaces
-- | Parse LaTeX and return 'Pandoc'.
parseLaTeX :: GenParser Char ParserState Pandoc
parseLaTeX = do
optional processLaTeXPreamble -- preamble might not be present (fragment)
spaces
blocks <- parseBlocks
spaces
optional $ try (string "\\end{document}" >> many anyChar)
-- might not be present (fragment)
spaces
eof
state <- getState
let blocks' = filter (/= Null) blocks
let title' = stateTitle state
let authors' = stateAuthors state
let date' = stateDate state
return $ Pandoc (Meta title' authors' date') blocks'
--
-- parsing blocks
--
parseBlocks :: GenParser Char ParserState [Block]
parseBlocks = spaces >> many block
block :: GenParser Char ParserState Block
block = choice [ hrule
, codeBlock
, header
, list
, blockQuote
, comment
, bibliographic
, para
, itemBlock
, unknownEnvironment
, ignore
, unknownCommand ] <?> "block"
--
-- header blocks
--
header :: GenParser Char ParserState Block
header = try $ do
char '\\'
subs <- many (try (string "sub"))
string "section"
optional (char '*')
char '{'
title' <- manyTill inline (char '}')
spaces
return $ Header (length subs + 1) (normalizeSpaces title')
--
-- hrule block
--
hrule :: GenParser Char st Block
hrule = oneOfStrings [ "\\begin{center}\\rule{3in}{0.4pt}\\end{center}\n\n",
"\\newpage" ] >> spaces >> return HorizontalRule
--
-- code blocks
--
codeBlock :: GenParser Char ParserState Block
codeBlock = codeBlockWith "verbatim" <|> codeBlockWith "Verbatim" <|> lhsCodeBlock
-- Note: Verbatim is from fancyvrb.
codeBlockWith :: String -> GenParser Char st Block
codeBlockWith env = try $ do
string ("\\begin{" ++ env ++ "}") -- don't use begin function because it
-- gobbles whitespace
optional blanklines -- we want to gobble blank lines, but not
-- leading space
contents <- manyTill anyChar (try (string $ "\\end{" ++ env ++ "}"))
spaces
let classes = if env == "code" then ["haskell"] else []
return $ CodeBlock ("",classes,[]) (stripTrailingNewlines contents)
lhsCodeBlock :: GenParser Char ParserState Block
lhsCodeBlock = do
failUnlessLHS
(CodeBlock (_,_,_) cont) <- codeBlockWith "code"
return $ CodeBlock ("", ["sourceCode","literate","haskell"], []) cont
--
-- block quotes
--
blockQuote :: GenParser Char ParserState Block
blockQuote = (environment "quote" <|> environment "quotation") >>~ spaces >>=
return . BlockQuote
--
-- list blocks
--
list :: GenParser Char ParserState Block
list = bulletList <|> orderedList <|> definitionList <?> "list"
listItem :: GenParser Char ParserState ([Inline], [Block])
listItem = try $ do
("item", _, args) <- command
spaces
state <- getState
let oldParserContext = stateParserContext state
updateState (\s -> s {stateParserContext = ListItemState})
blocks <- many block
updateState (\s -> s {stateParserContext = oldParserContext})
opt <- case args of
([x]) | "[" `isPrefixOf` x && "]" `isSuffixOf` x ->
parseFromString (many inline) $ tail $ init x
_ -> return []
return (opt, blocks)
orderedList :: GenParser Char ParserState Block
orderedList = try $ do
string "\\begin{enumerate}"
(_, style, delim) <- option (1, DefaultStyle, DefaultDelim) $
try $ do failIfStrict
char '['
res <- anyOrderedListMarker
char ']'
return res
spaces
option "" $ try $ do string "\\setlength{\\itemindent}"
char '{'
manyTill anyChar (char '}')
spaces
start <- option 1 $ try $ do failIfStrict
string "\\setcounter{enum"
many1 (oneOf "iv")
string "}{"
num <- many1 digit
char '}'
spaces
return $ (read num) + 1
items <- many listItem
end "enumerate"
spaces
return $ OrderedList (start, style, delim) $ map snd items
bulletList :: GenParser Char ParserState Block
bulletList = try $ do
begin "itemize"
spaces
items <- many listItem
end "itemize"
spaces
return (BulletList $ map snd items)
definitionList :: GenParser Char ParserState Block
definitionList = try $ do
begin "description"
spaces
items <- many listItem
end "description"
spaces
return (DefinitionList items)
--
-- paragraph block
--
para :: GenParser Char ParserState Block
para = do
res <- many1 inline
spaces
return $ if null (filter (`notElem` [Str "", Space]) res)
then Null
else Para $ normalizeSpaces res
--
-- title authors date
--
bibliographic :: GenParser Char ParserState Block
bibliographic = choice [ maketitle, title, authors, date ]
maketitle :: GenParser Char st Block
maketitle = try (string "\\maketitle") >> spaces >> return Null
title :: GenParser Char ParserState Block
title = try $ do
string "\\title{"
tit <- manyTill inline (char '}')
spaces
updateState (\state -> state { stateTitle = tit })
return Null
authors :: GenParser Char ParserState Block
authors = try $ do
string "\\author{"
authors' <- manyTill anyChar (char '}')
spaces
let authors'' = map removeLeadingTrailingSpace $ lines $
substitute "\\\\" "\n" authors'
updateState (\s -> s { stateAuthors = authors'' })
return Null
date :: GenParser Char ParserState Block
date = try $ do
string "\\date{"
date' <- manyTill anyChar (char '}')
spaces
updateState (\state -> state { stateDate = date' })
return Null
--
-- item block
-- for use in unknown environments that aren't being parsed as raw latex
--
-- this forces items to be parsed in different blocks
itemBlock :: GenParser Char ParserState Block
itemBlock = try $ do
("item", _, args) <- command
state <- getState
if stateParserContext state == ListItemState
then fail "item should be handled by list block"
else if null args
then return Null
else return $ Plain [Str (stripFirstAndLast (head args))]
--
-- raw LaTeX
--
-- | Parse any LaTeX environment and return a Para block containing
-- the whole literal environment as raw TeX.
rawLaTeXEnvironment :: GenParser Char st Block
rawLaTeXEnvironment = do
contents <- rawLaTeXEnvironment'
spaces
return $ Para [TeX contents]
-- | Parse any LaTeX environment and return a string containing
-- the whole literal environment as raw TeX.
rawLaTeXEnvironment' :: GenParser Char st String
rawLaTeXEnvironment' = try $ do
string "\\begin{"
name <- many1 letter
star <- option "" (string "*") -- for starred variants
let name' = name ++ star
char '}'
args <- option [] commandArgs
let argStr = concat args
contents <- manyTill (choice [ (many1 (noneOf "\\")),
rawLaTeXEnvironment',
string "\\" ])
(end name')
return $ "\\begin{" ++ name' ++ "}" ++ argStr ++
concat contents ++ "\\end{" ++ name' ++ "}"
unknownEnvironment :: GenParser Char ParserState Block
unknownEnvironment = try $ do
state <- getState
result <- if stateParseRaw state -- check whether we should include raw TeX
then rawLaTeXEnvironment -- if so, get whole raw environment
else anyEnvironment -- otherwise just the contents
return result
-- \ignore{} is used conventionally in literate haskell for definitions
-- that are to be processed by the compiler but not printed.
ignore :: GenParser Char ParserState Block
ignore = try $ do
("ignore", _, _) <- command
spaces
return Null
unknownCommand :: GenParser Char ParserState Block
unknownCommand = try $ do
notFollowedBy' $ choice $ map end ["itemize", "enumerate", "description",
"document"]
state <- getState
if stateParserContext state == ListItemState
then notFollowedBy' $ string "\\item"
else return ()
if stateParseRaw state
then do
(name, star, args) <- command
spaces
return $ Plain [TeX ("\\" ++ name ++ star ++ concat args)]
else do -- skip unknown command, leaving arguments to be parsed
char '\\'
letter
many (letter <|> digit)
optional (try $ string "{}")
spaces
return Null
-- latex comment
comment :: GenParser Char st Block
comment = try $ char '%' >> manyTill anyChar newline >> spaces >> return Null
--
-- inline
--
inline :: GenParser Char ParserState Inline
inline = choice [ str
, endline
, whitespace
, quoted
, apostrophe
, spacer
, strong
, math
, ellipses
, emDash
, enDash
, hyphen
, emph
, strikeout
, superscript
, subscript
, ref
, lab
, code
, url
, link
, image
, footnote
, linebreak
, accentedChar
, specialChar
, rawLaTeXInline
, escapedChar
, unescapedChar
] <?> "inline"
accentedChar :: GenParser Char st Inline
accentedChar = normalAccentedChar <|> specialAccentedChar
normalAccentedChar :: GenParser Char st Inline
normalAccentedChar = try $ do
char '\\'
accent <- oneOf "'`^\"~"
character <- (try $ char '{' >> letter >>~ char '}') <|> letter
let table = fromMaybe [] $ lookup character accentTable
let result = case lookup accent table of
Just num -> chr num
Nothing -> '?'
return $ Str [result]
-- an association list of letters and association list of accents
-- and decimal character numbers.
accentTable :: [(Char, [(Char, Int)])]
accentTable =
[ ('A', [('`', 192), ('\'', 193), ('^', 194), ('~', 195), ('"', 196)]),
('E', [('`', 200), ('\'', 201), ('^', 202), ('"', 203)]),
('I', [('`', 204), ('\'', 205), ('^', 206), ('"', 207)]),
('N', [('~', 209)]),
('O', [('`', 210), ('\'', 211), ('^', 212), ('~', 213), ('"', 214)]),
('U', [('`', 217), ('\'', 218), ('^', 219), ('"', 220)]),
('a', [('`', 224), ('\'', 225), ('^', 227), ('"', 228)]),
('e', [('`', 232), ('\'', 233), ('^', 234), ('"', 235)]),
('i', [('`', 236), ('\'', 237), ('^', 238), ('"', 239)]),
('n', [('~', 241)]),
('o', [('`', 242), ('\'', 243), ('^', 244), ('~', 245), ('"', 246)]),
('u', [('`', 249), ('\'', 250), ('^', 251), ('"', 252)]) ]
specialAccentedChar :: GenParser Char st Inline
specialAccentedChar = choice [ ccedil, aring, iuml, szlig, aelig,
oslash, pound, euro, copyright, sect ]
ccedil :: GenParser Char st Inline
ccedil = try $ do
char '\\'
letter' <- oneOfStrings ["cc", "cC"]
let num = if letter' == "cc" then 231 else 199
return $ Str [chr num]
aring :: GenParser Char st Inline
aring = try $ do
char '\\'
letter' <- oneOfStrings ["aa", "AA"]
let num = if letter' == "aa" then 229 else 197
return $ Str [chr num]
iuml :: GenParser Char st Inline
iuml = try (string "\\\"") >> oneOfStrings ["\\i", "{\\i}"] >>
return (Str [chr 239])
szlig :: GenParser Char st Inline
szlig = try (string "\\ss") >> return (Str [chr 223])
oslash :: GenParser Char st Inline
oslash = try $ do
char '\\'
letter' <- choice [char 'o', char 'O']
let num = if letter' == 'o' then 248 else 216
return $ Str [chr num]
aelig :: GenParser Char st Inline
aelig = try $ do
char '\\'
letter' <- oneOfStrings ["ae", "AE"]
let num = if letter' == "ae" then 230 else 198
return $ Str [chr num]
pound :: GenParser Char st Inline
pound = try (string "\\pounds") >> return (Str [chr 163])
euro :: GenParser Char st Inline
euro = try (string "\\euro") >> return (Str [chr 8364])
copyright :: GenParser Char st Inline
copyright = try (string "\\copyright") >> return (Str [chr 169])
sect :: GenParser Char st Inline
sect = try (string "\\S") >> return (Str [chr 167])
escapedChar :: GenParser Char st Inline
escapedChar = do
result <- escaped (oneOf " $%&_#{}\n")
return $ if result == Str "\n" then Str " " else result
-- nonescaped special characters
unescapedChar :: GenParser Char st Inline
unescapedChar = oneOf "`$^&_#{}|<>" >>= return . (\c -> Str [c])
specialChar :: GenParser Char st Inline
specialChar = choice [ backslash, tilde, caret, bar, lt, gt, doubleQuote ]
backslash :: GenParser Char st Inline
backslash = try (string "\\textbackslash") >> optional (try $ string "{}") >> return (Str "\\")
tilde :: GenParser Char st Inline
tilde = try (string "\\ensuremath{\\sim}") >> return (Str "~")
caret :: GenParser Char st Inline
caret = try (string "\\^{}") >> return (Str "^")
bar :: GenParser Char st Inline
bar = try (string "\\textbar") >> optional (try $ string "{}") >> return (Str "\\")
lt :: GenParser Char st Inline
lt = try (string "\\textless") >> optional (try $ string "{}") >> return (Str "<")
gt :: GenParser Char st Inline
gt = try (string "\\textgreater") >> optional (try $ string "{}") >> return (Str ">")
doubleQuote :: GenParser Char st Inline
doubleQuote = char '"' >> return (Str "\"")
code :: GenParser Char ParserState Inline
code = code1 <|> code2 <|> lhsInlineCode
code1 :: GenParser Char st Inline
code1 = try $ do
string "\\verb"
marker <- anyChar
result <- manyTill anyChar (char marker)
return $ Code $ removeLeadingTrailingSpace result
code2 :: GenParser Char st Inline
code2 = try $ do
string "\\texttt{"
result <- manyTill (noneOf "\\\n~$%^&{}") (char '}')
return $ Code result
lhsInlineCode :: GenParser Char ParserState Inline
lhsInlineCode = try $ do
failUnlessLHS
char '|'
result <- manyTill (noneOf "|\n") (char '|')
return $ Code result
emph :: GenParser Char ParserState Inline
emph = try $ oneOfStrings [ "\\emph{", "\\textit{" ] >>
manyTill inline (char '}') >>= return . Emph
strikeout :: GenParser Char ParserState Inline
strikeout = try $ string "\\sout{" >> manyTill inline (char '}') >>=
return . Strikeout
superscript :: GenParser Char ParserState Inline
superscript = try $ string "\\textsuperscript{" >>
manyTill inline (char '}') >>= return . Superscript
-- note: \textsubscript isn't a standard latex command, but we use
-- a defined version in pandoc.
subscript :: GenParser Char ParserState Inline
subscript = try $ string "\\textsubscript{" >> manyTill inline (char '}') >>=
return . Subscript
apostrophe :: GenParser Char ParserState Inline
apostrophe = char '\'' >> return Apostrophe
quoted :: GenParser Char ParserState Inline
quoted = doubleQuoted <|> singleQuoted
singleQuoted :: GenParser Char ParserState Inline
singleQuoted = enclosed singleQuoteStart singleQuoteEnd inline >>=
return . Quoted SingleQuote . normalizeSpaces
doubleQuoted :: GenParser Char ParserState Inline
doubleQuoted = enclosed doubleQuoteStart doubleQuoteEnd inline >>=
return . Quoted DoubleQuote . normalizeSpaces
singleQuoteStart :: GenParser Char st Char
singleQuoteStart = char '`'
singleQuoteEnd :: GenParser Char st ()
singleQuoteEnd = try $ char '\'' >> notFollowedBy alphaNum
doubleQuoteStart :: CharParser st String
doubleQuoteStart = string "``"
doubleQuoteEnd :: CharParser st String
doubleQuoteEnd = try $ string "''"
ellipses :: GenParser Char st Inline
ellipses = try $ string "\\ldots" >> optional (try $ string "{}") >>
return Ellipses
enDash :: GenParser Char st Inline
enDash = try (string "--") >> return EnDash
emDash :: GenParser Char st Inline
emDash = try (string "---") >> return EmDash
hyphen :: GenParser Char st Inline
hyphen = char '-' >> return (Str "-")
lab :: GenParser Char st Inline
lab = try $ do
string "\\label{"
result <- manyTill anyChar (char '}')
return $ Str $ "(" ++ result ++ ")"
ref :: GenParser Char st Inline
ref = try (string "\\ref{") >> manyTill anyChar (char '}') >>= return . Str
strong :: GenParser Char ParserState Inline
strong = try (string "\\textbf{") >> manyTill inline (char '}') >>=
return . Strong
whitespace :: GenParser Char st Inline
whitespace = many1 (oneOf "~ \t") >> return Space
-- hard line break
linebreak :: GenParser Char st Inline
linebreak = try (string "\\\\") >> return LineBreak
spacer :: GenParser Char st Inline
spacer = try (string "\\,") >> return (Str "")
str :: GenParser Char st Inline
str = many1 (noneOf specialChars) >>= return . Str
-- endline internal to paragraph
endline :: GenParser Char st Inline
endline = try $ newline >> notFollowedBy blankline >> return Space
-- math
math :: GenParser Char st Inline
math = (math3 >>= return . Math DisplayMath)
<|> (math1 >>= return . Math InlineMath)
<|> (math2 >>= return . Math InlineMath)
<|> (math4 >>= return . Math DisplayMath)
<|> (math5 >>= return . Math DisplayMath)
<|> (math6 >>= return . Math DisplayMath)
<?> "math"
math1 :: GenParser Char st String
math1 = try $ char '$' >> manyTill anyChar (char '$')
math2 :: GenParser Char st String
math2 = try $ string "\\(" >> manyTill anyChar (try $ string "\\)")
math3 :: GenParser Char st String
math3 = try $ char '$' >> math1 >>~ char '$'
math4 :: GenParser Char st String
math4 = try $ do
name <- begin "displaymath" <|> begin "equation" <|> begin "equation*" <|>
begin "gather" <|> begin "gather*" <|> begin "gathered" <|>
begin "multline" <|> begin "multline*"
spaces
manyTill anyChar (end name)
math5 :: GenParser Char st String
math5 = try $ (string "\\[") >> spaces >> manyTill anyChar (try $ string "\\]")
math6 :: GenParser Char st String
math6 = try $ do
name <- begin "eqnarray" <|> begin "eqnarray*" <|> begin "align" <|>
begin "align*" <|> begin "alignat" <|> begin "alignat*" <|>
begin "split" <|> begin "aligned" <|> begin "alignedat"
spaces
res <- manyTill anyChar (end name)
return $ filter (/= '&') res -- remove alignment codes
--
-- links and images
--
url :: GenParser Char ParserState Inline
url = try $ do
string "\\url"
url' <- charsInBalanced '{' '}'
return $ Link [Code url'] (url', "")
link :: GenParser Char ParserState Inline
link = try $ do
string "\\href{"
url' <- manyTill anyChar (char '}')
char '{'
label' <- manyTill inline (char '}')
return $ Link (normalizeSpaces label') (url', "")
image :: GenParser Char ParserState Inline
image = try $ do
("includegraphics", _, args) <- command
let args' = filter isArg args -- filter out options
let src = if null args' then
("", "")
else
(stripFirstAndLast (head args'), "")
return $ Image [Str "image"] src
footnote :: GenParser Char ParserState Inline
footnote = try $ do
(name, _, (contents:[])) <- command
if ((name == "footnote") || (name == "thanks"))
then string ""
else fail "not a footnote or thanks command"
let contents' = stripFirstAndLast contents
-- parse the extracted block, which may contain various block elements:
rest <- getInput
setInput $ contents'
blocks <- parseBlocks
setInput rest
return $ Note blocks
-- | Parse any LaTeX command and return it in a raw TeX inline element.
rawLaTeXInline :: GenParser Char ParserState Inline
rawLaTeXInline = try $ do
notFollowedBy' $ oneOfStrings ["\\begin", "\\end", "\\item", "\\ignore"]
state <- getState
if stateParseRaw state
then do
(name, star, args) <- command
return $ TeX ("\\" ++ name ++ star ++ concat args)
else do -- skip unknown command, leaving arguments to be parsed
char '\\'
letter
many (letter <|> digit)
optional (try $ string "{}")
return $ Str ""