Pandoc: Is there a way to include an appendix of links in a PDF from markdown? - pdf

Question

I use Markdown and Pandoc extensively. However, I would like to generate a PDF with embedded links (like usual), but in the event the document is printed, I'd like to also include a table of links at the end of the document. Is there a way to do this automatically?
Ex.
Title
-----
[Python][] is cool!
...
## Links ##
[Python]: http://python.org
[Pip]: https://pip.readthedocs.org
where I would actually get an extra page in my PDF with something like
Python: http://python.org
Pip: https://pip.readthedocs.org
Thanks!

Answer 1

This is something that is easy to achieve with filters.
Here is linkTable.hs. A filter which adds a table of links to the end of your document.
import Text.Pandoc.JSON
import Text.Pandoc.Walk
import Data.Monoid
main :: IO ()
main = toJSONFilter appendLinkTable
appendLinkTable :: Pandoc -> Pandoc
appendLinkTable (Pandoc m bs) = Pandoc m (bs ++ linkTable bs)
linkTable :: [Block] -> [Block]
linkTable p = [Header 2 ("linkTable", [], []) [Str "Links"] , Para links]
where
links = concatMap makeRow $ query getLink p
getLink (Link txt (url, _)) = [(url,txt)]
getLink _ = []
makeRow (url, txt) = txt ++ [Str ":", Space, Link [Str url] (url, ""), LineBreak]
Compile the filter with ghc linkTable.hs. The output is as follows.
> ghc linkTable.hs
[1 of 1] Compiling Main ( linkTable.hs, linkTable.o )
Linking linkTable ...
> cat example.md
Title
-----
[Python][] is cool!
[Pip] is a package manager.
...
[Python]: http://python.org
[Pip]: https://pip.readthedocs.org
Then running pandoc with the filter.
> pandoc -t markdown --filter=./linkTable example.md
Title
-----
[Python](http://python.org) is cool!
[Pip](https://pip.readthedocs.org) is a package manager.
...
Links {#linkTable}
-----
Python: <http://python.org>\
Pip: <https://pip.readthedocs.org>\