 
   ## Examples
 
+      iex> callback = fn (result) -> {:ok, result} end
+      iex> Cmark.to_commonmark(~s(Something "smart" and ... ---you get it!), callback, [:smart])
+      {:ok, "Something “smart” and … —you get it\\!\n"}
+
       iex> callback = fn (results) ->
       iex>   Enum.map(results, &String.strip/1) |> Enum.join("%%joiner%%")
       iex> end

  and calls function with result.

  ## Examples

      iex> callback = fn (results) ->
      iex>   Enum.map(results, &String.strip/1) |> Enum.join("<joiner>")

          <text>“</text>\n    <text>smart</text>\n    <text>”</text>\n    <text> quotes</text>\n    <text>.</text>
        </paragraph>\n</document>\n"

      iex> Cmark.to_xml([~s(Something "smart"), ~s(em---dashed)], [:smart])
      ["<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<!DOCTYPE document SYSTEM \"CommonMark.dtd\">
      <document xmlns=\"http://commonmark.org/xml/1.0\">\n  <paragraph>\n    <text>Something </text>
          <text>“</text>\n    <text>smart</text>\n    <text>”</text>\n  </paragraph>\n</document>\n",
      "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<!DOCTYPE document SYSTEM \"CommonMark.dtd\">
      <document xmlns=\"http://commonmark.org/xml/1.0\">\n  <paragraph>\n    <text>em</text>
          <text>—</text>\n    <text>dashed</text>\n  </paragraph>\n</document>\n"]

  -----

  Compiles one or more (list) Markdown documents to XML and calls function with result.
