Generate changelog for oj gem

generate-oj-changelog.rb

#!/usr/bin/env ruby
require 'nokogiri'
require 'open-uri'

entries = []
current_entry = nil

doc = Nokogiri::HTML(open('http://www.ohler.com/dev/oj_misc/release_notes.html'))
body = doc.at_css('.content_box')
body.children.each do |cur|
  text = cur.text.strip
  next if text.empty?
  case cur.name
  when 'p'
    entries << current_entry if current_entry
    raise "Unknown format: #{text}" unless /^Release (?<version>\S+) \[(?<date>.+)\]$/ =~ text
    current_entry = {
      version: version,
      date: Date.parse(date),
      changes: []
    }
  when 'ul'
    current_entry[:changes] += cur.search('li').map { |li| li.text.strip.gsub(/\n\s+/, ' ') }
  end
end
entries << current_entry if current_entry

puts '# CHANGELOG'
puts
puts '## Unreleased'
puts

entries.each do |entry|
  puts "## #{entry[:version]} - #{entry[:date]}"
  puts
  entry[:changes].each do |ch|
    puts "- #{ch}"
  end
  puts
end