markdown_converter.rb

module Jekyll

  # This is probably bad. Should I be doing this?

  class MarkdownConverter < Converter
    alias :old_convert :convert

    def convert(content)
      old_convert(content).gsub(/<h([1-6])>(.+?<\/)/) do |match|
        n = $1
        text = $2
        "<h#{n} id=\"#{slugify(text)}\">#{text}"
      end
    end

    def slugify(text)
      text.strip.downcase.
        gsub(/[^a-z0-9]+/, '-'). # Replace non-alphanumeric characters with -
        gsub(/-$|^-/, '')        # Remove trailing and leading -'s
    end

  end

end