Q:

Redcarpet Footnotes extension not working

I am trying to get linked footnotes to work but somehow Redcarpet simply is not recognizing the footnote extension I am passing into the initialiser.
I am running Redcarpet version  3.3.4, which should have the footnotes functionality merged into master as discussed in these posts: Post 1
Post 2
Customer Renderer
        class CustomMarkdownParser < Redcarpet::Render::HTML
    include ActionView::Helpers::UrlHelper
    include ActionView::Helpers::AssetTagHelper
    include AbstractController::Rendering

    def block_code(code, language)
        Pygments.highlight(code, lexer: language)
    end

    def parse_media_link(link)
    end

    def image(link, title, alt_text)
    end

    def link(link, title, content)
    end

    #def footnote_def(content, number)
    #end

    #def footnote_ref(number)
    #end
end

markdown function in application_helper
def md_parser(content)
    puts "Parsing Markdown"
    renderer = CustomMarkdownParser.new(
            hard_wrap: true,
            filter_html: true,
            with_toc_data: true)

    options ={

    }

    markdown = Redcarpet::Markdown.new(renderer,
                                       autolink: true, # detect links and wrap them in link tags
                                       no_intra_emphasis: true, # ensures _ inside words are not repolaced with <em> tags
                                       disable_indented_code_blocks: true, # does not convert lines prefixed with 4 spaces
                                       fenced_code_blocks: true,
                                       lax_spacing: true,
                                       strikethrough: true,
                                       footnotes: true,
                                       superscript: true,
                                       tables: true,
                                       underline: true
    )

    markdown.render(content).html_safe
end

I had a look atthe gem's code and it lists the following extensions:
EXTENSION_MAP = {
# old name => new name
:autolink         => :autolink,
:fenced_code      => :fenced_code_blocks,
:filter_html      => :filter_html,
:hard_wrap        => :hard_wrap,
:prettify         => :prettify,
:lax_htmlblock    => :lax_spacing,
:no_image         => :no_images,
:no_intraemphasis => :no_intra_emphasis,
:no_links         => :no_links,
:filter_styles    => :no_styles,
:safelink         => :safe_links_only,
:space_header     => :space_after_headers,
:strikethrough    => :strikethrough,
:tables           => :tables,
:generate_toc     => :with_toc_data,
:xhtml            => :xhtml,

# old names with no new mapping
:gh_blockcode => nil,
:no_tables    => nil,
:smart        => nil,
:strict       => nil
}

I am not sure why footnotes is not included.
The output i receive is this (read ^ as superscript, the closing square bracket is superscripted as well):
    Atlantic[^1],
    [^1] This is the footnote

A:

In your custom renderer you override the methods handling footnotes so they don’t do anything. Just remove those methods (footnote_def and footnote_ref) and allow the originals to run.
Additionally, the syntax for footnote definitions requires a colon which you seem to be missing:
[^1]: This is the footnote

