aboutsummaryrefslogtreecommitdiff
path: root/src/Text/Pandoc/Readers/Org/Shared.hs
blob: 07dbeca2ad80521bfcb711498a80d93e5b080a18 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE OverloadedStrings #-}
{-
Copyright (C) 2014-2018 Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>

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.Org.Shared
   Copyright   : Copyright (C) 2014-2018 Albert Krewinkel
   License     : GNU GPL, version 2 or above

   Maintainer  : Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>

Utility functions used in other Pandoc Org modules.
-}
module Text.Pandoc.Readers.Org.Shared
  ( cleanLinkString
  , isImageFilename
  , originalLang
  , translateLang
  ) where

import Prelude
import Data.Char (isAlphaNum)
import Data.List (isPrefixOf, isSuffixOf)


-- | Check whether the given string looks like the path to of URL of an image.
isImageFilename :: String -> Bool
isImageFilename filename =
  any (\x -> ('.':x)  `isSuffixOf` filename) imageExtensions &&
  (any (\x -> (x ++ "://") `isPrefixOf` filename) protocols ||
   ':' `notElem` filename)
 where
   imageExtensions = [ "jpeg" , "jpg" , "png" , "gif" , "svg" ]
   protocols = [ "file", "http", "https" ]

-- | Cleanup and canonicalize a string describing a link.  Return @Nothing@ if
-- the string does not appear to be a link.
cleanLinkString :: String -> Maybe String
cleanLinkString s =
  case s of
    '/':_                  -> Just $ "file://" ++ s  -- absolute path
    '.':'/':_              -> Just s                 -- relative path
    '.':'.':'/':_          -> Just s                 -- relative path
    -- Relative path or URL (file schema)
    'f':'i':'l':'e':':':s' -> Just $ if "//" `isPrefixOf` s' then s else s'
    _                      | isUrl s            -> Just s                 -- URL
    _                      -> Nothing
 where
   isUrl :: String -> Bool
   isUrl cs =
     let (scheme, path) = break (== ':') cs
     in all (\c -> isAlphaNum c || c `elem` (".-"::String)) scheme
          && not (null path)

-- | Creates an key-value pair marking the original language name specified for
-- a piece of source code.

-- | Creates an key-value attributes marking the original language name
-- specified for a piece of source code.
originalLang :: String -> [(String, String)]
originalLang lang =
  let transLang = translateLang lang
  in if transLang == lang
     then []
     else [("org-language", lang)]

-- | Translate from Org-mode's programming language identifiers to those used
-- by Pandoc.  This is useful to allow for proper syntax highlighting in
-- Pandoc output.
translateLang :: String -> String
translateLang cs =
  case cs of
    "C"          -> "c"
    "C++"        -> "cpp"
    "emacs-lisp" -> "commonlisp" -- emacs lisp is not supported
    "js"         -> "javascript"
    "lisp"       -> "commonlisp"
    "R"          -> "r"
    "sh"         -> "bash"
    "sqlite"     -> "sql"
    _            -> cs