Re: pandoc as a linkchecker?

[Albert Krewinkel <albert+pandoc-9EawChwDxG8hFhg+JK9F0w@public.gmane.org>]

Joseph Reagle writes:

> It's time to check which links in my syllabi are broken, and I'm again
> cursing under my breath that there's no multi-format linkchecker out
> there that can report line numbers. Then I thought, what about my
> favorite tool!?

Well, here's an anchor checking Lua filter which will tell you when a
link points to a nonexistent anchor. Should be not too hard to extend to
check external links as well. You won't get line numbers, though.

    local identifiers = {}
    function collect_ids (x)
      if x.identifier and x.identifier ~= '' then
        identifiers[x.identifier] = true
      end
    end

    function check_link (link)
      -- check internal links
      if link.target:sub(1,1) == '#' then
        local target_exists = identifiers[link.target:sub(2)]
        if not target_exists then
          io.stderr:write(
            table.concat {'Invalid target: ', link.target,
              ' (link text is "', pandoc.utils.stringify(link), '")\n'
            }
          )
        end
      end
    end

    return {
      {Block = collect_ids, Inline = collect_ids},
      {Link = check_link}
    }


--
Albert Krewinkel
GPG: 8eed e3e2 e8c5 6f18 81fe  e836 388d c0b2 1f63 1124