Evaluating and updating annotations in ruby code in markdown files

sib_render_markdown.rb

require 'redcarpet' # gem
require 'open3'     # stdlib
class SibRenderer < Redcarpet::Render::Safe
  def block_code(code, language)
    if language == "ruby"
      code, _status = Open3.capture2("seeing_is_believing", "--xmpfilter-style", stdin_data: code)
    end
    super code, language                                     # prob what you really want, see somefile.correctly_escaped.html
    %(<pre><code class="#{language}">\n#{code}</code></pre>) # better for this example, see somefile.from_example.html
  end
end

markdown = Redcarpet::Markdown.new(SibRenderer.new, fenced_code_blocks: true)
puts markdown.render File.read ARGV.first

somefile.correctly_escaped.html

<h1>Here is some ruby:</h1>
<pre><code>&quot;abc&quot;
  .upcase    # =&gt; &quot;ABC&quot;
  .chars     # =&gt; [&quot;A&quot;, &quot;B&quot;, &quot;C&quot;]
  .join(&quot;&#x2F;&quot;) # =&gt; &quot;A&#x2F;B&#x2F;C&quot;
</code></pre>

somefile.from_example.html

<h1>Here is some ruby:</h1>
<pre><code class="ruby">
"abc"
  .upcase    # => "ABC"
  .chars     # => ["A", "B", "C"]
  .join("/") # => "A/B/C"
</code></pre>

somefile.md

Here is some ruby:

"abc"
  .upcase    # =>
  .chars     # =>
  .join("/") # =>