parse-markdown.liquid

{% comment %}

Firstly, we can't comment inside liquid  tags, so this turned into a mess pretty quickly.
In order to somewhat document this mess, I'll do my best without writing the comments inline :(



This snippet takes in a string variable called "raw", parses it for markdown, and spits out the
corresponding HTML representation


Currently, this only supports h1, h2, h3, strong, em, ul, and a
So something like this works just fine:

##Some Headline
###Some subheadline
**Lorem dolor** sit amet, consectetur adipiscing elit, **sed** do eiusmod tempor
ut labore [first one](https://www.google.com) et dolore magna aliqua.
Ut enim ad minim **veniam** [second](https://www.bing.com)
- Feature 1
- Feature 2
- Feature 3



The general logic here is simple for some elements, and complicated for others.
h1-h3 are simple, but don't support nesting behavior (i.e. can't put <strong> inside an <h1>)

The logic for p-tags is where it gets a little more convoluted.
Generally, the algorithm for inserting <strong> and <em> tags are the same, just a tag difference.
The <a>-tag-inserting function works a little differently since we need to rearrange the markup a little
after extracting the href and tag text values.

{% endcomment %}

{% liquid

  assign lines = raw | newline_to_br | split: '<br />'

  assign list_is_open = false


  for line in lines

      assign tag = ""
      assign subline = line | strip
      assign line_start = subline | slice: 0
      assign line_is_list_item = false


      comment
        Skip this line if its just an empty newline tag
      endcomment
      if subline == "\n" or subline == ""
        continue
      endif




      comment
        H1 - H3 are simplistic
      endcomment
      if line contains "###"
        assign tag = "h3"
      elsif line contains "##"
        assign tag = "h2"
      elsif line contains "#"
        assign tag = "h1"


      elsif line_start == "-"

        if list_is_open == false
          echo "<ul>"
        endif

        assign line_is_list_item = true
        assign list_is_open = true
        assign tag = "li"
        assign subline = subline | slice: 1,subline.size | strip

      else


        assign tag = "p"
        if line contains "**"

          assign full_subline = ""
          assign subline_split = line | split:"**"
          assign forloop_count = subline_split | size
          for sub_split in subline_split

            assign forloop_mod = forloop.index0 | modulo: 2
            if forloop_mod == 0 and forloop.index != forloop_count
              assign full_subline = full_subline | append: sub_split | append: "<strong>"
            else
              assign full_subline = full_subline | append: sub_split | append: "</strong>"
            endif

          endfor

          assign subline = full_subline | replace:"**", ""
        endif



        if line contains "*"

          assign full_subline = ""
          assign subline_split = subline | split:"*"
          assign forloop_count = subline_split | size
          for sub_split in subline_split

            assign forloop_mod = forloop.index0 | modulo: 2
            if forloop_mod == 0 and forloop.index != forloop_count
              assign full_subline = full_subline | append: sub_split | append: "<em>"
            else
              assign full_subline = full_subline | append: sub_split | append: "</em>"
            endif

          endfor

          assign subline = full_subline | replace:"*", ""
        endif


        if line contains "]("

          assign subline_split = subline | split:"["
          assign forloop_count = subline_split | size

          for sub_split in subline_split

            if sub_split contains "]("
              assign link_title = sub_split | split: "]("
              assign link_title = link_title[0]

              assign link_url = sub_split | split: "]("
              assign link_url = link_url[1] | split: ")"
              assign link_url = link_url[0]

              assign real_link = "<a href='" | append: link_url | append:"'>" | append: link_title | append: "</a>"
              assign to_replace = "[" | append: link_title | append: "](" | append:link_url | append:")"
              assign subline = subline | replace: to_replace, real_link

            endif

          endfor



        endif



      endif



      if line_is_list_item == false and list_is_open
        echo "</ul>"
        assign list_is_open = false
      endif


      assign clean_full_line = subline | replace:"#", ""
      assign tag_start = "<" | append: tag | append: ">"
      assign tag_end = "</" | append: tag | append: ">"


      echo tag_start | append: clean_full_line | append: tag_end
  endfor

%}