simple commandline tool to output an outline from a markdown document to the terminal

markdown_outline.rb

#!/usr/bin/env ruby
# markdown outline
# simple commandline tool to output an outline from a markdown document to the terminal

require 'rubygems'
require 'redcarpet'


class OutlineRenderer < Redcarpet::Render::HTML
  attr_accessor :outline

  def initialize
    @outline = []
    super
  end

  def header(text, header_level)
    self.outline << [header_level, text]
    ""
  end
end

def format_outline(outline)
  outline.map do |level, text|
    spaces = ''
    ((level - 1) * 4).times{spaces << ' '}
    "#{spaces} #{text}"
  end.join("\n")
end

renderer = OutlineRenderer.new
r = Redcarpet::Markdown.new(renderer)
content = r.render(File.read(File.expand_path(ARGV[0])))
outline = renderer.outline
puts format_outline(outline)