├── BlockParser.hs
└── README.md


/BlockParser.hs:
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 1 | module BlockParser where
 2 |   
 3 | import Text.Parsec
 4 | import Text.Parsec.String
 5 | import Control.Applicative hiding (many, (<|>))
 6 | 
 7 | data Item =
 8 |     Text String
 9 |   | Block String [Item]
10 |   deriving Show
11 | 
12 | type CharParser st = Parsec [Char] st
13 | 
14 | -- A item is either a block delimited
15 | -- by \begin{name} \end{name}
16 | -- or plain text
17 | item :: CharParser st Item
18 | item =  
19 |   do
20 |     blockName <- begin
21 |     Block blockName <$> blockBody <* end blockName
22 |   <|> text
23 | 
24 | -- series of items (including nested blocks)
25 | blockBody :: CharParser st [Item]
26 | blockBody = many item
27 | 
28 | -- \begin{name}
29 | -- returns name or fails
30 | begin :: CharParser st String
31 | begin = try $ string "\\begin" *> braced
32 | 
33 | -- tries \end{str} for a given string
34 | end :: String -> CharParser st String
35 | end str = try $
36 |   string "\\end" *> between (char '{') (char '}') (string str)
37 |   
38 | -- string delimited by braces
39 | braced :: CharParser st String
40 | braced = between (char '{') (char '}') (many $ noneOf "}")
41 | 
42 | -- a non-empty string of characters other than \ $ { }
43 | text :: CharParser st Item
44 | text = Text <$> many1 (noneOf "\\${}")
45 |   
46 | test :: String
47 | test = 
48 |   let file = "\\begin{foo}abc\\begin{bar}def\\end{bar}\\begin{baz}ghi\\end{baz}\\end{foo}" 
49 |   in
50 |     case parse item "Experiment" file of
51 |         Left err -> "Error: " ++ show err
52 |         Right doc -> show doc
53 | 


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/README.md:
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1 | # Parsing
2 | Using parsec
3 | 


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