toc-md.rb

#!/usr/bin/env ruby

FORBIDDEN_WORDS = ['Table of contents', 'define', 'pragma'].freeze

def should_skip_line?(line)
  !line.start_with?("#") || FORBIDDEN_WORDS.any? { |word| line =~ /#{word}/ }
end

File.open(ARGV[0], 'r') do |f|
  in_code_block = false
  f.each_line do |line|
    in_code_block = !in_code_block if line =~ (/```/)
    next if should_skip_line?(line) || in_code_block
    title = line.tr("#", "").strip
    href = title.tr(" ", "-").downcase
    puts "  " * (line.count("#")-1) + "* [#{title}](\##{href})"
  end
end