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{- Copyright © 2015 Benjamin Barenblat
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 3 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, see <http://www.gnu.org/licenses/>. -}
module Weave (weave) where
import Control.Monad (liftM)
import Data.Functor ((<$>))
import Fragment
weave :: [Fragment] -> Either String String
weave = concatMapM weaveFragment
weaveFragment :: Fragment -> Either String String
weaveFragment (Documentation text) = Right text
weaveFragment (BlockCode name body) = do
escapeCharacter <- texEscape <$> pickTexEscapeCharacter body
return $ "\\begin{LytBlockCode}{" ++ name ++ "}{" ++ escapeCharacter ++ "}\n"
++ weaveBlockBody escapeCharacter body
++ "\\end{LytBlockCode}\n"
weaveBlockBody :: String -> [CodeOrReference] -> String
weaveBlockBody escapeCharacter ((Code first):rest) =
{- The first block is code. To make sure it gets typeset correctly, drop
everything up to the first newline or non-space character. -}
(case dropWhile (==' ') first of
'\n' : first' -> first'
first' -> first')
++ concatMap (weaveCodeOrReference escapeCharacter) rest
weaveBlockBody escapeCharacter blocks =
concatMap (weaveCodeOrReference escapeCharacter) blocks
weaveCodeOrReference :: String -> CodeOrReference -> String
weaveCodeOrReference _ (Code text) = text
weaveCodeOrReference escapeCharacter (Reference name) =
escapeCharacter ++ "\\LytFragmentReference{" ++ name ++ "}" ++ escapeCharacter
pickTexEscapeCharacter :: [CodeOrReference] -> Either String Char
pickTexEscapeCharacter blocks =
case firstNotIn (consolidate blocks) texPotentialEscapeCharacters of
Just c -> Right c
Nothing -> Left "could not find a suitable LaTeX escape character"
where consolidate = foldl (\current block -> case block of
Code text -> current ++ text
Reference _ -> current)
""
firstNotIn :: Eq a => [a] -> [a] -> Maybe a
firstNotIn _ [] = Nothing
firstNotIn haystack (x:xs)
| x `elem` haystack = firstNotIn haystack xs
| otherwise = Just x
texPotentialEscapeCharacters :: [Char]
texPotentialEscapeCharacters =
"!@#$%^&*()-_+={}[]|\"':;/?,.~`" ++ ['A' .. 'Z' ] ++ ['a' .. 'z']
texEscape :: Char -> String
texEscape char
| char `elem` "#$%^&_{}~" = ['\\', char]
| otherwise = [char]
concatMapM :: Monad m => (a -> m [b]) -> [a] -> m [b]
concatMapM f lists = liftM concat $ mapM f lists
|
