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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.Shared
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
Utility functions and definitions used by the various Pandoc modules.
-}
module Text.Pandoc.Shared (
-- * List processing
splitBy,
splitByIndices,
substitute,
-- * Text processing
joinWithSep,
tabsToSpaces,
backslashEscape,
endsWith,
stripTrailingNewlines,
removeLeadingTrailingSpace,
removeLeadingSpace,
removeTrailingSpace,
stripFirstAndLast,
-- * Parsing
readWith,
testStringWith,
HeaderType (..),
ParserContext (..),
QuoteContext (..),
ParserState (..),
defaultParserState,
-- * Native format prettyprinting
prettyPandoc,
-- * Pandoc block list processing
isNoteBlock,
normalizeSpaces,
compactify,
generateReference,
WriterOptions (..),
defaultWriterOptions,
KeyTable,
keyTable,
lookupKeySrc,
refsMatch,
replaceReferenceLinks,
replaceRefLinksBlockList,
-- * SGML
inTags,
selfClosingTag,
inTagsSimple,
inTagsIndented
) where
import Text.Pandoc.Definition
import Text.ParserCombinators.Parsec as Parsec
import Text.Pandoc.Entities ( decodeEntities, escapeSGMLString )
import Text.PrettyPrint.HughesPJ as PP ( text, char, (<>),
($$), nest, Doc, isEmpty )
import Data.Char ( toLower, ord )
import Data.List ( find, groupBy, isPrefixOf )
-- | Parse a string with a given parser and state.
readWith :: GenParser Char ParserState a -- ^ parser
-> ParserState -- ^ initial state
-> String -- ^ input string
-> a
readWith parser state input =
case runParser parser state "source" input of
Left err -> error $ "\nError:\n" ++ show err
Right result -> result
-- | Parse a string with @parser@ (for testing).
testStringWith :: (Show a) =>
GenParser Char ParserState a
-> String
-> IO ()
testStringWith parser str = putStrLn $ show $
readWith parser defaultParserState str
data HeaderType
= SingleHeader Char -- ^ Single line of characters underneath
| DoubleHeader Char -- ^ Lines of characters above and below
deriving (Eq, Show)
data ParserContext
= ListItemState -- ^ Used when running parser on list item contents
| NullState -- ^ Default state
deriving (Eq, Show)
data QuoteContext
= InSingleQuote -- ^ Used when we're parsing inside single quotes
| InDoubleQuote -- ^ Used when we're parsing inside double quotes
| NoQuote -- ^ Used when we're not parsing inside quotes
deriving (Eq, Show)
data ParserState = ParserState
{ stateParseRaw :: Bool, -- ^ Parse untranslatable HTML
-- and LaTeX?
stateParserContext :: ParserContext, -- ^ What are we parsing?
stateQuoteContext :: QuoteContext, -- ^ Inside quoted environment?
stateKeyBlocks :: [Block], -- ^ List of reference key blocks
stateKeysUsed :: [[Inline]], -- ^ List of references used
stateNoteBlocks :: [Block], -- ^ List of note blocks
stateNoteIdentifiers :: [String], -- ^ List of footnote identifiers
-- in the order encountered
stateTabStop :: Int, -- ^ Tab stop
stateStandalone :: Bool, -- ^ If @True@, parse
-- bibliographic info
stateTitle :: [Inline], -- ^ Title of document
stateAuthors :: [String], -- ^ Authors of document
stateDate :: String, -- ^ Date of document
stateStrict :: Bool, -- ^ Use strict markdown syntax
stateSmart :: Bool, -- ^ Use smart typography
stateColumns :: Int, -- ^ Number of columns in
-- terminal (used for tables)
stateInlineLinks :: Bool, -- ^ Parse html links as inline
stateHeaderTable :: [HeaderType] -- ^ List of header types used,
-- in what order (rst only)
}
deriving Show
defaultParserState :: ParserState
defaultParserState =
ParserState { stateParseRaw = False,
stateParserContext = NullState,
stateQuoteContext = NoQuote,
stateKeyBlocks = [],
stateKeysUsed = [],
stateNoteBlocks = [],
stateNoteIdentifiers = [],
stateTabStop = 4,
stateStandalone = False,
stateTitle = [],
stateAuthors = [],
stateDate = [],
stateStrict = False,
stateSmart = False,
stateColumns = 80,
stateInlineLinks = False,
stateHeaderTable = [] }
-- | Indent string as a block.
indentBy :: Int -- ^ Number of spaces to indent the block
-> Int -- ^ Number of spaces (rel to block) to indent first line
-> String -- ^ Contents of block to indent
-> String
indentBy num first [] = ""
indentBy num first str =
let (firstLine:restLines) = lines str
firstLineIndent = num + first in
(replicate firstLineIndent ' ') ++ firstLine ++ "\n" ++ (joinWithSep "\n" $ map (\line -> (replicate num ' ') ++ line) restLines)
-- | Prettyprint list of Pandoc blocks elements.
prettyBlockList :: Int -- ^ Number of spaces to indent list of blocks
-> [Block] -- ^ List of blocks
-> String
prettyBlockList indent [] = indentBy indent 0 "[]"
prettyBlockList indent blocks = indentBy indent (-2) $ "[ " ++
(joinWithSep "\n, " (map prettyBlock blocks)) ++ " ]"
-- | Prettyprint Pandoc block element.
prettyBlock :: Block -> String
prettyBlock (BlockQuote blocks) = "BlockQuote\n " ++
(prettyBlockList 2 blocks)
prettyBlock (Note ref blocks) = "Note " ++ (show ref) ++ "\n " ++
(prettyBlockList 2 blocks)
prettyBlock (OrderedList blockLists) =
"OrderedList\n" ++ indentBy 2 0 ("[ " ++ (joinWithSep ", "
(map (\blocks -> prettyBlockList 2 blocks) blockLists))) ++ " ]"
prettyBlock (BulletList blockLists) = "BulletList\n" ++
indentBy 2 0 ("[ " ++ (joinWithSep ", "
(map (\blocks -> prettyBlockList 2 blocks) blockLists))) ++ " ]"
prettyBlock (DefinitionList blockLists) = "DefinitionList\n" ++
indentBy 2 0 ("[ " ++ (joinWithSep ", "
(map (\(term, blocks) -> "(" ++ show term ++ ",\n" ++
indentBy 1 2 (prettyBlockList 2 blocks) ++ ")") blockLists))) ++ " ]"
prettyBlock block = show block
-- | Prettyprint Pandoc document.
prettyPandoc :: Pandoc -> String
prettyPandoc (Pandoc meta blocks) = "Pandoc " ++ "(" ++ (show meta) ++
")\n" ++ (prettyBlockList 0 blocks) ++ "\n"
-- | Convert tabs to spaces (with adjustable tab stop).
tabsToSpaces :: Int -- ^ Tabstop
-> String -- ^ String to convert
-> String
tabsToSpaces tabstop str =
unlines (map (tabsInLine tabstop tabstop) (lines str))
-- | Convert tabs to spaces in one line.
tabsInLine :: Int -- ^ Number of spaces to next tab stop
-> Int -- ^ Tabstop
-> String -- ^ Line to convert
-> String
tabsInLine num tabstop "" = ""
tabsInLine num tabstop (c:cs) =
let replacement = (if (c == '\t') then (replicate num ' ') else [c]) in
let nextnumraw = (num - (length replacement)) in
let nextnum = if (nextnumraw < 1)
then (nextnumraw + tabstop)
else nextnumraw in
replacement ++ (tabsInLine nextnum tabstop cs)
-- | Escape designated characters with backslash.
backslashEscape :: [Char] -- ^ list of special characters to escape
-> String -- ^ string input
-> String
backslashEscape special [] = []
backslashEscape special (x:xs) = if x `elem` special
then '\\':x:(backslashEscape special xs)
else x:(backslashEscape special xs)
-- | Returns @True@ if string ends with given character.
endsWith :: Char -> [Char] -> Bool
endsWith char [] = False
endsWith char str = (char == last str)
-- | Returns @True@ if block is a @Note@ block
isNoteBlock :: Block -> Bool
isNoteBlock (Note ref blocks) = True
isNoteBlock _ = False
-- | Joins a list of lists, separated by another list.
joinWithSep :: [a] -- ^ List to use as separator
-> [[a]] -- ^ Lists to join
-> [a]
joinWithSep sep [] = []
joinWithSep sep lst = foldr1 (\a b -> a ++ sep ++ b) lst
-- | Strip trailing newlines from string.
stripTrailingNewlines :: String -> String
stripTrailingNewlines "" = ""
stripTrailingNewlines str =
if (last str) == '\n'
then stripTrailingNewlines (init str)
else str
-- | Remove leading and trailing space (including newlines) from string.
removeLeadingTrailingSpace :: String -> String
removeLeadingTrailingSpace = removeLeadingSpace . removeTrailingSpace
-- | Remove leading space (including newlines) from string.
removeLeadingSpace :: String -> String
removeLeadingSpace = dropWhile (\x -> (x == ' ') || (x == '\n') ||
(x == '\t'))
-- | Remove trailing space (including newlines) from string.
removeTrailingSpace :: String -> String
removeTrailingSpace = reverse . removeLeadingSpace . reverse
-- | Strip leading and trailing characters from string
stripFirstAndLast str =
drop 1 $ take ((length str) - 1) str
-- | Replace each occurrence of one sublist in a list with another.
substitute :: (Eq a) => [a] -> [a] -> [a] -> [a]
substitute _ _ [] = []
substitute [] _ lst = lst
substitute target replacement lst =
if isPrefixOf target lst
then replacement ++ (substitute target replacement $ drop (length target) lst)
else (head lst):(substitute target replacement $ tail lst)
-- | Split list into groups separated by sep.
splitBy :: (Eq a) => a -> [a] -> [[a]]
splitBy _ [] = []
splitBy sep lst =
let (first, rest) = break (== sep) lst
rest' = dropWhile (== sep) rest in
first:(splitBy sep rest')
-- | Split list into chunks divided at specified indices.
splitByIndices :: [Int] -> [a] -> [[a]]
splitByIndices [] lst = [lst]
splitByIndices (x:xs) lst =
let (first, rest) = splitAt x lst in
first:(splitByIndices (map (\y -> y - x) xs) rest)
-- | Normalize a list of inline elements: remove leading and trailing
-- @Space@ elements, collapse double @Space@s into singles, and
-- remove empty Str elements.
normalizeSpaces :: [Inline] -> [Inline]
normalizeSpaces [] = []
normalizeSpaces list =
let removeDoubles [] = []
removeDoubles (Space:Space:rest) = removeDoubles (Space:rest)
removeDoubles ((Str ""):rest) = removeDoubles rest
removeDoubles (x:rest) = x:(removeDoubles rest) in
let removeLeading [] = []
removeLeading lst = if ((head lst) == Space)
then tail lst
else lst in
let removeTrailing [] = []
removeTrailing lst = if ((last lst) == Space)
then init lst
else lst in
removeLeading $ removeTrailing $ removeDoubles list
-- | Change final list item from @Para@ to @Plain@ if the list should
-- be compact.
compactify :: [[Block]] -- ^ List of list items (each a list of blocks)
-> [[Block]]
compactify [] = []
compactify items =
let final = last items
others = init items in
case final of
[Para a] -> if any containsPara others
then items
else others ++ [[Plain a]]
otherwise -> items
containsPara :: [Block] -> Bool
containsPara [] = False
containsPara ((Para a):rest) = True
containsPara ((BulletList items):rest) = (any containsPara items) ||
(containsPara rest)
containsPara ((OrderedList items):rest) = (any containsPara items) ||
(containsPara rest)
containsPara (x:rest) = containsPara rest
-- | Options for writers
data WriterOptions = WriterOptions
{ writerStandalone :: Bool -- ^ Include header and footer
, writerTitlePrefix :: String -- ^ Prefix for HTML titles
, writerHeader :: String -- ^ Header for the document
, writerIncludeBefore :: String -- ^ String to include before the body
, writerIncludeAfter :: String -- ^ String to include after the body
, writerS5 :: Bool -- ^ We're writing S5
, writerIncremental :: Bool -- ^ Incremental S5 lists
, writerNumberSections :: Bool -- ^ Number sections in LaTeX
, writerStrictMarkdown :: Bool -- ^ Use strict markdown syntax
, writerTabStop :: Int -- ^ Tabstop for conversion between
-- spaces and tabs
, writerNotes :: [Block] -- ^ List of note blocks
} deriving Show
-- | Default writer options.
defaultWriterOptions =
WriterOptions { writerStandalone = True,
writerHeader = "",
writerTitlePrefix = "",
writerTabStop = 4,
writerNotes = [],
writerS5 = False,
writerIncremental = False,
writerNumberSections = False,
writerIncludeBefore = "",
writerIncludeAfter = "",
writerStrictMarkdown = False }
--
-- Functions for constructing lists of reference keys
--
-- | Returns @Just@ numerical key reference if there's already a key
-- for the specified target in the list of blocks, otherwise @Nothing@.
keyFoundIn :: [Block] -- ^ List of key blocks to search
-> Target -- ^ Target to search for
-> Maybe String
keyFoundIn [] src = Nothing
keyFoundIn ((Key [Str num] src1):rest) src = if (src1 == src)
then Just num
else keyFoundIn rest src
keyFoundIn (_:rest) src = keyFoundIn rest src
-- | Return next unique numerical key, given keyList
nextUniqueKey :: [[Inline]] -> String
nextUniqueKey keys =
let nums = [1..10000]
notAKey n = not (any (== [Str (show n)]) keys) in
case (find notAKey nums) of
Just x -> show x
Nothing -> error "Could not find unique key for reference link"
-- | Generate a reference for a URL (either an existing reference, if
-- there is one, or a new one, if there isn't) and update parser state.
generateReference :: String -- ^ URL
-> String -- ^ Title
-> GenParser tok ParserState Target
generateReference url title = do
let src = Src (decodeEntities url) (decodeEntities title)
state <- getState
let keyBlocks = stateKeyBlocks state
let keysUsed = stateKeysUsed state
case (keyFoundIn keyBlocks src) of
Just num -> return (Ref [Str num])
Nothing -> do
let nextNum = nextUniqueKey keysUsed
updateState (\st -> st { stateKeyBlocks =
(Key [Str nextNum] src):keyBlocks,
stateKeysUsed =
[Str nextNum]:keysUsed })
return (Ref [Str nextNum])
--
-- code to replace reference links with real links and remove unneeded key blocks
--
type KeyTable = [([Inline], Target)]
-- | Returns @True@ if block is a Key block
isRefBlock :: Block -> Bool
isRefBlock (Key _ _) = True
isRefBlock _ = False
-- | Returns a pair of a list of pairs of keys and associated sources, and a new
-- list of blocks with the included key blocks deleted.
keyTable :: [Block] -> (KeyTable, [Block])
keyTable [] = ([],[])
keyTable ((Key ref target):lst) = (((ref, target):table), rest)
where (table, rest) = keyTable lst
keyTable (Null:lst) = keyTable lst -- get rid of Nulls
keyTable (Blank:lst) = keyTable lst -- get rid of Blanks
keyTable (other:lst) = (table, (other:rest))
where (table, rest) = keyTable lst
-- | Look up key in key table and return target object.
lookupKeySrc :: KeyTable -- ^ Key table
-> [Inline] -- ^ Key
-> Maybe Target
lookupKeySrc table key = case table of
[] -> Nothing
(k, src):rest -> if (refsMatch k key)
then Just src
else lookupKeySrc rest key
-- | Returns @True@ if keys match (case insensitive).
refsMatch :: [Inline] -> [Inline] -> Bool
refsMatch ((Str x):restx) ((Str y):resty) =
((map toLower x) == (map toLower y)) && refsMatch restx resty
refsMatch ((Code x):restx) ((Code y):resty) =
((map toLower x) == (map toLower y)) && refsMatch restx resty
refsMatch ((TeX x):restx) ((TeX y):resty) =
((map toLower x) == (map toLower y)) && refsMatch restx resty
refsMatch ((HtmlInline x):restx) ((HtmlInline y):resty) =
((map toLower x) == (map toLower y)) && refsMatch restx resty
refsMatch ((NoteRef x):restx) ((NoteRef y):resty) =
((map toLower x) == (map toLower y)) && refsMatch restx resty
refsMatch ((Emph x):restx) ((Emph y):resty) =
refsMatch x y && refsMatch restx resty
refsMatch ((Strong x):restx) ((Strong y):resty) =
refsMatch x y && refsMatch restx resty
refsMatch ((Quoted t x):restx) ((Quoted u y):resty) =
t == u && refsMatch x y && refsMatch restx resty
refsMatch (x:restx) (y:resty) = (x == y) && refsMatch restx resty
refsMatch [] x = null x
refsMatch x [] = null x
-- | Replace reference links with explicit links in list of blocks,
-- removing key blocks.
replaceReferenceLinks :: [Block] -> [Block]
replaceReferenceLinks blocks =
let (keytable, purged) = keyTable blocks in
replaceRefLinksBlockList keytable purged
-- | Use key table to replace reference links with explicit links in a list
-- of blocks
replaceRefLinksBlockList :: KeyTable -> [Block] -> [Block]
replaceRefLinksBlockList keytable lst =
map (replaceRefLinksBlock keytable) lst
-- | Use key table to replace reference links with explicit links in a block
replaceRefLinksBlock :: KeyTable -> Block -> Block
replaceRefLinksBlock keytable (Plain lst) =
Plain (map (replaceRefLinksInline keytable) lst)
replaceRefLinksBlock keytable (Para lst) =
Para (map (replaceRefLinksInline keytable) lst)
replaceRefLinksBlock keytable (Header lvl lst) =
Header lvl (map (replaceRefLinksInline keytable) lst)
replaceRefLinksBlock keytable (BlockQuote lst) =
BlockQuote (map (replaceRefLinksBlock keytable) lst)
replaceRefLinksBlock keytable (Note ref lst) =
Note ref (map (replaceRefLinksBlock keytable) lst)
replaceRefLinksBlock keytable (OrderedList lst) =
OrderedList (map (replaceRefLinksBlockList keytable) lst)
replaceRefLinksBlock keytable (BulletList lst) =
BulletList (map (replaceRefLinksBlockList keytable) lst)
replaceRefLinksBlock keytable (DefinitionList lst) =
DefinitionList (map (\(term, def) ->
(map (replaceRefLinksInline keytable) term,
replaceRefLinksBlockList keytable def)) lst)
replaceRefLinksBlock keytable (Table caption alignment widths headers rows) =
Table (map (replaceRefLinksInline keytable) caption) alignment widths
(map (replaceRefLinksBlockList keytable) headers)
(map (map (replaceRefLinksBlockList keytable)) rows)
replaceRefLinksBlock keytable other = other
-- | Use key table to replace reference links with explicit links in an
-- inline element.
replaceRefLinksInline :: KeyTable -> Inline -> Inline
replaceRefLinksInline keytable (Link text (Ref ref)) = (Link newText newRef)
where newRef = case lookupKeySrc keytable
(if (null ref) then text else ref) of
Nothing -> (Ref ref)
Just src -> src
newText = map (replaceRefLinksInline keytable) text
replaceRefLinksInline keytable (Image text (Ref ref)) = (Image newText newRef)
where newRef = case lookupKeySrc keytable
(if (null ref) then text else ref) of
Nothing -> (Ref ref)
Just src -> src
newText = map (replaceRefLinksInline keytable) text
replaceRefLinksInline keytable (Emph lst) =
Emph (map (replaceRefLinksInline keytable) lst)
replaceRefLinksInline keytable (Strong lst) =
Strong (map (replaceRefLinksInline keytable) lst)
replaceRefLinksInline keytable (Quoted t lst) =
Quoted t (map (replaceRefLinksInline keytable) lst)
replaceRefLinksInline keytable other = other
-- | Return a text object with a string of formatted SGML attributes.
attributeList :: [(String, String)] -> Doc
attributeList = text . concatMap
(\(a, b) -> " " ++ escapeSGMLString a ++ "=\"" ++
escapeSGMLString b ++ "\"")
-- | Put the supplied contents between start and end tags of tagType,
-- with specified attributes and (if specified) indentation.
inTags:: Bool -> String -> [(String, String)] -> Doc -> Doc
inTags isIndented tagType attribs contents =
let openTag = PP.char '<' <> text tagType <> attributeList attribs <>
PP.char '>'
closeTag = text "</" <> text tagType <> PP.char '>' in
if isIndented
then openTag $$ nest 2 contents $$ closeTag
else openTag <> contents <> closeTag
-- | Return a self-closing tag of tagType with specified attributes
selfClosingTag :: String -> [(String, String)] -> Doc
selfClosingTag tagType attribs =
PP.char '<' <> text tagType <> attributeList attribs <> text " />"
-- | Put the supplied contents between start and end tags of tagType.
inTagsSimple :: String -> Doc -> Doc
inTagsSimple tagType = inTags False tagType []
-- | Put the supplied contents in indented block btw start and end tags.
inTagsIndented :: String -> Doc -> Doc
inTagsIndented tagType = inTags True tagType []
|