Octopress plugin for including poem translations in a page.

include_poem.rb

# Title: Include Poem Tag for Jekyll
# Author: Max Eskin http://maxeskin.com
# Description: Import files on your filesystem into any blog post as embedded text snippets with line numbers.
#
# Syntax {% include_poem key=value ... %}
#
# Keys:
# left - Specifies file for left column (use this if only a single column is desired)
# right - File for right column 
# title - Title
#
# Example 1:
# {% include_poem left=raven.txt %}
#
# This will import raven.txt from source/raven.txt
#
# Example 2:
# You can also include an optional title for the <figcaption>
#
# {% include_poem title="The Raven" left=raven.txt %}
#
# will output a figcaption with the title: The Raven 
#

require './plugins/raw'
require 'pathname'

module Jekyll

  class IncludePoemTag < Liquid::Tag
    include TemplateWrapper

    def initialize(tag_name, markup, tokens)
      h = Hash[markup.scan(/(?:"(?:\\.|[^"])*"|[^" ])+/).map { |l| l.chomp.split('=', 2) }]
      @title = h.fetch('title', '').gsub('"', '')
      @file = h.fetch('left', '')
      @right_file = h.fetch('right', nil)

      super
    end


    def read_poem(context, file, title)
      site = context.registers[:site]

      converter = site.getConverterImpl(::Jekyll::MarkdownConverter)

      poem = converter.convert(file.read)

      poem.gsub!(/<\/?p>/, '')

      footnote_start_string = '<div class="footnotes">'
      footnote_index = poem.index(footnote_start_string)
      footnote = ''

      if footnote_index
        clean_title = title.gsub(/[^a-zA-Z0-9]/, '')
        footnote_start = footnote_index + footnote_start_string.length
        footnote = poem[footnote_start..-10]
        poem = poem[0..footnote_index-1]

        poem.gsub!('"#fn:', '"#' + clean_title + 'fn:')
        footnote.gsub!('"fn:', '"' + clean_title + 'fn:')
        poem.gsub!('"fnref:', '"' + clean_title + 'fnref:')
        footnote.gsub!('"#fnref:', '"#' + clean_title + 'fnref:')
        footnote.gsub!('<hr/>', '')
      end
      return poem, footnote
    end

    def render(context)
      poem_path = (Pathname.new(context.registers[:site].source)).expand_path
      file = poem_path + @file

      right_file = ''
      if @right_file
        right_file = poem_path + @right_file
      end

      unless file.file?
        return "file #{file} could not be found"
      end

      if @right_file && !right_file.file?
        return "file #{right_file} could not be found"
      end

      Dir.chdir(poem_path) do
        title = @title != '' ? "#{@title}" : @file

        poem, footnote = read_poem(context, file, title)

        right_poem = ''
        right_footnote = ''
        if @right_file
          right_poem, right_footnote = read_poem(context, right_file, title + '2')
        end

        url = "{@file}"
        source = "<figure class='code'>\n\t<figcaption><span>#{title}</span></figcaption>"
        table = tableize_poem(poem, right_poem, footnote + right_footnote)
        source += "#{table}\n</figure>"

        safe_wrap(source)
      end
    end

    def tableize_poem (str, right_str='', footnotes='')
      table = '<div class="highlight"><table style="border-collapse:separate">'

      lines = 0
      total_rows = str.lines.count
      total_cols = right_str ? 4 : 2

      str.lines.each_with_index do |line, index|
        number = ''
        empty_line = line.strip == ''

        if !empty_line
          lines = lines+1
          number = lines
        end

        table += '<tr>'

        # If the line is empty, we want to preserve the default vertical padding to achieve a blank space
        number_style = empty_line ? "style='vertical-align:top'" : "style='vertical-align:top;padding-top:0;padding-bottom:0'"
        table += "<td class='line-numbers' #{number_style}>#{number}</td>"

        left_style = right_str == '' ? "style='vertical-align:top'" : "style='vertical-align:top; width:50%'"
        table += "<td class='code' #{left_style}>#{format_line(line)}</td>"

        if right_str != ''
          # Divider
          if index == 0
            table += "<td rowspan=#{total_rows} style='background-color:#cacccd;border-color:#2c3e50;border-style:solid;border-width:5px;' width='1px'></td>"
          end

          right_line = right_str.lines[index]

          table += "<td class='code' style='vertical-align:top'>#{format_line(right_line)}</td>"

        end

        table += "</tr>\n"
      end

      footnote_row = ''
      if footnotes != ''
        footnote_row = "<tr><td colspan=#{total_cols} class='code-title' style='border-top-left-radius:0px; border-top-right-radius:0px; text-align:left'>#{footnotes}</td></tr>"
      end

      table += "#{footnote_row}</table></div>"
    end

    def format_line(line)
      "<pre style='font-family:inherit; word-break:normal' class='line'>#{line.strip}</pre>"
    end
  end
end

Liquid::Template.register_tag('include_poem', Jekyll::IncludePoemTag)