Git Project Language Blob Overtime

tableme.rb

# calculates language blob values ala github over time
# requires the github-linguist gem
#
# It's how I made this pretty graph http://www.flickr.com/photos/baroquebobcat/9401947827/
require 'rubygems'
require 'linguist'
require 'date'

def each_day start, finish
  (start..finish).each do |day|
    yield day
  end
end

language_list = []

first_date = `git rev-list --parents HEAD | egrep "^[a-f0-9]{40}$" | xargs git log | grep Date:`.split[1..-1].join " "
last_commit = ""

each_day Date.parse(first_date), Date.today do |date|
  sha = `git rev-list -n 1 --before=\"#{date}\" master`
  next if sha == last_commit
  msg =`git checkout #{sha} 2>&1`
  if msg.include? 'Abort'
    raise msg
  end
  
  project = Linguist::Repository.from_directory(".")
  language_list << [date, project.languages]
  last_commit = sha
end
keys = language_list.map{|date, langs| langs.keys}.flatten.uniq
puts ["date",keys].flatten.join("\t")
language_list.each do |date, langs|
  puts [date, keys.map{|k|langs[k]||0}].flatten.join("\t")
end