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|
{-# LANGUAGE OverloadedStrings #-}
{- |
Module : Text.Pandoc.Readers.Org.Shared
Copyright : Copyright (C) 2014-2021 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
( cleanLinkText
, isImageFilename
, originalLang
, translateLang
, exportsCode
) where
import Data.Char (isAlphaNum)
import Data.Text (Text)
import qualified Data.Text as T
import System.FilePath (isValid, takeExtension)
import Text.Pandoc.Shared (elemText)
-- | Check whether the given string looks like the path to of URL of an image.
isImageFilename :: Text -> Bool
isImageFilename fp = hasImageExtension && (isValid (T.unpack fp) || isKnownProtocolUri)
where
hasImageExtension = takeExtension (T.unpack $ T.toLower fp)
`elem` imageExtensions
isKnownProtocolUri = any (\x -> (x <> "://") `T.isPrefixOf` fp) protocols
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.
cleanLinkText :: Text -> Maybe Text
cleanLinkText s
| Just _ <- T.stripPrefix "/" s = Just $ "file://" <> s -- absolute path
| Just _ <- T.stripPrefix "./" s = Just s -- relative path
| Just _ <- T.stripPrefix "../" s = Just s -- relative path
-- Relative path or URL (file schema)
| Just s' <- T.stripPrefix "file:" s = Just $ if "//" `T.isPrefixOf` s' then s else s'
| otherwise = if isUrl s then Just s else Nothing
where
isUrl :: Text -> Bool
isUrl cs =
let (scheme, path) = T.break (== ':') cs
in T.all (\c -> isAlphaNum c || c `elemText` ".-") scheme
&& not (T.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 :: Text -> [(Text, Text)]
originalLang lang =
let transLang = translateLang lang
in [("org-language", lang) | transLang /= 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 :: Text -> Text
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
exportsCode :: [(Text, Text)] -> Bool
exportsCode = maybe True (`elem` ["code", "both"]) . lookup "exports"
|
