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|
{-
Copyright (C) 2006 John MacFarlane <jgm at berkeley dot 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 John MacFarlane
License : GNU GPL, version 2 or above
Maintainer : John MacFarlane <jgm at berkeley dot 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.ParserCombinators.Pandoc
import Text.Pandoc.Definition
import Text.Pandoc.Shared
import Maybe ( fromMaybe )
import Char ( chr )
-- | Parse LaTeX from string and return 'Pandoc' document.
readLaTeX :: ParserState -- ^ Parser state, including options for parser
-> String -- ^ String to parse
-> Pandoc
readLaTeX = readWith parseLaTeX
-- for testing
testString = testStringWith parseLaTeX
-- characters with special meaning
specialChars = "\\$%&^&_~#{}\n \t|<>'\"-"
--
-- utility functions
--
-- | Returns text between brackets and its matching pair.
bracketedText openB closeB = try (do
char openB
result <- many (choice [ oneOfStrings [ ['\\', openB], ['\\', closeB] ],
count 1 (noneOf [openB, closeB]),
bracketedText openB closeB ])
char closeB
return ([openB] ++ (concat result) ++ [closeB]))
-- | Returns an option or argument of a LaTeX command.
optOrArg = choice [ (bracketedText '{' '}'), (bracketedText '[' ']') ]
-- | True if the string begins with '{'.
isArg ('{':rest) = True
isArg other = False
-- | Returns list of options and arguments of a LaTeX command.
commandArgs = many optOrArg
-- | Parses LaTeX command, returns (name, star, list of options or arguments).
command = try (do
char '\\'
name <- many1 alphaNum
star <- option "" (string "*") -- some commands have starred versions
args <- commandArgs
return (name, star, args))
begin name = try (do
string "\\begin{"
string name
char '}'
option [] commandArgs
spaces
return name)
end name = try (do
string "\\end{"
string name
char '}'
spaces
return name)
-- | Returns a list of block elements containing the contents of an
-- environment.
environment name = try (do
begin name
spaces
contents <- manyTill block (end name)
return contents)
anyEnvironment = try (do
string "\\begin{"
name <- many alphaNum
star <- option "" (string "*") -- some environments have starred variants
char '}'
option [] commandArgs
spaces
contents <- manyTill block (end (name ++ star))
return (BlockQuote contents))
--
-- parsing documents
--
-- | Process LaTeX preamble, extracting metadata.
processLaTeXPreamble = try (do
manyTill (choice [bibliographic, comment, unknownCommand, nullBlock])
(try (string "\\begin{document}"))
spaces)
-- | Parse LaTeX and return 'Pandoc'.
parseLaTeX = do
option () processLaTeXPreamble -- preamble might not be present (fragment)
blocks <- parseBlocks
spaces
option "" (try (string "\\end{document}")) -- might not be present (in fragment)
spaces
eof
state <- getState
let keyBlocks = stateKeyBlocks state
let noteBlocks = stateNoteBlocks state
let blocks' = filter (/= Null) blocks
let title' = stateTitle state
let authors' = stateAuthors state
let date' = stateDate state
return (Pandoc (Meta title' authors' date')
(blocks' ++ (reverse noteBlocks) ++ (reverse keyBlocks)))
--
-- parsing blocks
--
parseBlocks = do
spaces
result <- many block
return result
block = choice [ hrule, codeBlock, header, list, blockQuote, mathBlock,
comment, bibliographic, para, specialEnvironment,
itemBlock, unknownEnvironment, unknownCommand ] <?>
"block"
--
-- header blocks
--
header = choice (map headerLevel (enumFromTo 1 5)) <?> "header"
headerLevel n = try (do
let subs = concat $ replicate (n - 1) "sub"
string ("\\" ++ subs ++ "section")
option ' ' (char '*')
char '{'
title <- manyTill inline (char '}')
spaces
return (Header n (normalizeSpaces title)))
--
-- hrule block
--
hrule = try (do
oneOfStrings [ "\\begin{center}\\rule{3in}{0.4pt}\\end{center}\n\n",
"\\newpage" ]
spaces
return HorizontalRule)
--
-- code blocks
--
codeBlock = try (do
string "\\begin{verbatim}" -- don't use begin function because it
-- gobbles whitespace
option "" blanklines -- we want to gobble blank lines, but not
-- leading space
contents <- manyTill anyChar (try (string "\\end{verbatim}"))
spaces
return (CodeBlock (stripTrailingNewlines contents)))
--
-- block quotes
--
blockQuote = choice [ blockQuote1, blockQuote2 ] <?> "blockquote"
blockQuote1 = try (do
blocks <- environment "quote"
spaces
return (BlockQuote blocks))
blockQuote2 = try (do
blocks <- environment "quotation"
spaces
return (BlockQuote blocks))
--
-- math block
--
mathBlock = mathBlockWith (begin "equation") (end "equation") <|>
mathBlockWith (begin "displaymath") (end "displaymath") <|>
mathBlockWith (string "\\[") (string "\\]") <?> "math block"
mathBlockWith start end = try (do
start
spaces
result <- manyTill anyChar end
spaces
return (BlockQuote [Para [TeX ("$" ++ result ++ "$")]]))
--
-- list blocks
--
list = bulletList <|> orderedList <?> "list"
listItem = try (do
("item", _, _) <- command
spaces
state <- getState
let oldParserContext = stateParserContext state
updateState (\state -> state {stateParserContext = ListItemState})
blocks <- many block
updateState (\state -> state {stateParserContext = oldParserContext})
return blocks)
orderedList = try (do
begin "enumerate"
spaces
items <- many listItem
end "enumerate"
spaces
return (OrderedList items))
bulletList = try (do
begin "itemize"
spaces
items <- many listItem
end "itemize"
spaces
return (BulletList items))
--
-- paragraph block
--
para = try (do
result <- many1 inline
spaces
return (Para (normalizeSpaces result)))
--
-- title authors date
--
bibliographic = choice [ maketitle, title, authors, date ]
maketitle = try (do
string "\\maketitle"
spaces
return Null)
title = try (do
string "\\title{"
tit <- manyTill inline (char '}')
spaces
updateState (\state -> state { stateTitle = tit })
return Null)
authors = try (do
string "\\author{"
authors <- manyTill anyChar (char '}')
spaces
let authors' = map removeLeadingTrailingSpace $ lines $
substitute "\\\\" "\n" authors
updateState (\state -> state { stateAuthors = authors' })
return Null)
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 = 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
--
specialEnvironment = do -- these are always parsed as raw
followedBy' (choice (map (\name -> begin name) ["tabular", "figure",
"tabbing", "eqnarry", "picture", "table", "verse", "theorem"]))
rawLaTeXEnvironment
-- | Parse any LaTeX environment and return a Para block containing
-- the whole literal environment as raw TeX.
rawLaTeXEnvironment :: GenParser Char st Block
rawLaTeXEnvironment = try (do
string "\\begin"
char '{'
name <- many1 alphaNum
star <- option "" (string "*") -- for starred variants
let name' = name ++ star
char '}'
args <- option [] commandArgs
let argStr = concat args
contents <- manyTill (choice [(many1 (noneOf "\\")),
(do
(Para [TeX str]) <- rawLaTeXEnvironment
return str),
string "\\" ])
(end name')
spaces
return (Para [TeX ("\\begin{" ++ name' ++ "}" ++ argStr ++
(concat contents) ++ "\\end{" ++ name' ++ "}")]))
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)
unknownCommand = try (do
notFollowedBy' (string "\\end{itemize}")
notFollowedBy' (string "\\end{enumerate}")
notFollowedBy' (string "\\end{document}")
(name, star, args) <- command
spaces
let argStr = concat args
state <- getState
if (name == "item") && ((stateParserContext state) == ListItemState)
then fail "should not be parsed as raw"
else string ""
if stateParseRaw state
then return (Plain [TeX ("\\" ++ name ++ star ++ argStr)])
else return (Plain [Str (joinWithSep " " args)]))
-- latex comment
comment = try (do
char '%'
result <- manyTill anyChar newline
spaces
return Null)
--
-- inline
--
inline = choice [ strong, emph, ref, lab, code, linebreak, spacer,
math, ellipses,
emDash, enDash, hyphen, quoted, apostrophe,
accentedChar, specialChar, specialInline, escapedChar,
unescapedChar, str, endline, whitespace ] <?> "inline"
specialInline = choice [ link, image, footnote, rawLaTeXInline ]
<?> "link, raw TeX, note, or image"
accentedChar = normalAccentedChar <|> specialAccentedChar
normalAccentedChar = try (do
char '\\'
accent <- oneOf "'`^\"~"
character <- choice [ between (char '{') (char '}') anyChar, anyChar ]
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 =
[ ('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 = choice [ ccedil, aring, iuml, szlig, aelig,
oslash, pound, euro, copyright, sect ]
ccedil = try (do
char '\\'
letter <- choice [try (string "cc"), try (string "cC")]
let num = if letter == "cc" then 231 else 199
return (Str [chr num]))
aring = try (do
char '\\'
letter <- choice [try (string "aa"), try (string "AA")]
let num = if letter == "aa" then 229 else 197
return (Str [chr num]))
iuml = try (do
string "\\\""
choice [try (string "\\i"), try (string "{\\i}")]
return (Str [chr 239]))
icirc = try (do
string "\\^"
choice [try (string "\\i"), try (string "{\\i}")]
return (Str [chr 238]))
szlig = try (do
string "\\ss"
return (Str [chr 223]))
oslash = try (do
char '\\'
letter <- choice [char 'o', char 'O']
let num = if letter == 'o' then 248 else 216
return (Str [chr num]))
aelig = try (do
char '\\'
letter <- choice [try (string "ae"), try (string "AE")]
let num = if letter == "ae" then 230 else 198
return (Str [chr num]))
pound = try (do
string "\\pounds"
return (Str [chr 163]))
euro = try (do
string "\\euro"
return (Str [chr 8364]))
copyright = try (do
string "\\copyright"
return (Str [chr 169]))
sect = try (do
string "\\S"
return (Str [chr 167]))
escapedChar = do
result <- escaped (oneOf " $%^&_#{}\n")
return (if result == Str "\n" then Str " " else result)
unescapedChar = do -- ignore standalone, nonescaped special characters
oneOf "$^&_#{}|<>"
return (Str "")
specialChar = choice [ backslash, bar, lt, gt ]
backslash = try (do
string "\\textbackslash"
return (Str "\\"))
bar = try (do
string "\\textbar"
return (Str "\\"))
lt = try (do
string "\\textless"
return (Str "<"))
gt = try (do
string "\\textgreater"
return (Str ">"))
code = try (do
string "\\verb"
marker <- anyChar
result <- manyTill anyChar (char marker)
let result' = removeLeadingTrailingSpace result
return (Code result'))
emph = try (do
oneOfStrings [ "\\emph{", "\\textit{" ]
result <- manyTill inline (char '}')
return (Emph result))
apostrophe = do
char '\''
return Apostrophe
quoted = do
doubleQuoted <|> singleQuoted
singleQuoted = try (do
result <- enclosed singleQuoteStart singleQuoteEnd inline
return $ Quoted SingleQuote $ normalizeSpaces result)
doubleQuoted = try (do
result <- enclosed doubleQuoteStart doubleQuoteEnd inline
return $ Quoted DoubleQuote $ normalizeSpaces result)
singleQuoteStart = char '`'
singleQuoteEnd = try (do
char '\''
notFollowedBy alphaNum)
doubleQuoteStart = try (string "``")
doubleQuoteEnd = try (string "''")
ellipses = try (do
string "\\ldots"
option "" (try (string "{}"))
return Ellipses)
enDash = try (do
string "--"
notFollowedBy (char '-')
return EnDash)
emDash = try (do
string "---"
return EmDash)
hyphen = do
char '-'
return (Str "-")
lab = try (do
string "\\label{"
result <- manyTill anyChar (char '}')
return (Str ("(" ++ result ++ ")")))
ref = try (do
string "\\ref{"
result <- manyTill anyChar (char '}')
return (Str (result)))
strong = try (do
string "\\textbf{"
result <- manyTill inline (char '}')
return (Strong result))
whitespace = do
many1 (oneOf "~ \t")
return Space
-- hard line break
linebreak = try (do
string "\\\\"
return LineBreak)
spacer = try $ do
string "\\,"
return (Str "")
str = do
result <- many1 (noneOf specialChars)
return (Str result)
-- endline internal to paragraph
endline = try (do
newline
notFollowedBy blankline
return Space)
-- math
math = math1 <|> math2 <?> "math"
math1 = try (do
char '$'
result <- many (noneOf "$")
char '$'
return (TeX ("$" ++ result ++ "$")))
math2 = try (do
string "\\("
result <- many (noneOf "$")
string "\\)"
return (TeX ("$" ++ result ++ "$")))
--
-- links and images
--
link = try (do
string "\\href{"
url <- manyTill anyChar (char '}')
char '{'
label <- manyTill inline (char '}')
return (Link (normalizeSpaces label) (Src url "")))
image = try (do
("includegraphics", _, args) <- command
let args' = filter isArg args -- filter out options
let src = if null args' then
Src "" ""
else
Src (stripFirstAndLast (head args')) ""
return (Image [Str "image"] src))
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
state <- getState
let notes = stateNoteBlocks state
let nextRef = case notes of
[] -> "1"
(Note ref body):rest -> (show ((read ref) + 1))
setState (state { stateNoteBlocks = (Note nextRef blocks):notes })
return (NoteRef nextRef))
-- | Parse any LaTeX command and return it in a raw TeX inline element.
rawLaTeXInline :: GenParser Char ParserState Inline
rawLaTeXInline = try (do
(name, star, args) <- command
let argStr = concat args
state <- getState
if ((name == "begin") || (name == "end") || (name == "item"))
then fail "not an inline command"
else string ""
return (TeX ("\\" ++ name ++ star ++ argStr)))
|