platex が使える事が前提。
日本語に対応しています。
namespace :c do

  task :default => "all"

  task :setup do
    @name = "plan_booklog"
  end

  task :tex1 =>[:setup] do
    mkdir "output" unless File.exists? "output"
    sh "platex -kanji=utf8 -output-directory=output #{@name}.tex"
  end

  task :bibtex do
    if File.exists? File.join(File.dirname(__FILE__), %w{ reference.bib }) then
      if(RUBY_PLATFORM.downcase =~ /mswin(?!ce)|mingw|cygwin|bccwin/) then
	sh "pbibtex -kanji=utf8 output/#{@name}"
      else
	sh "jbibtex -kanji=utf8 output/#{@name}"
      end
      sh "platex -kanji=utf8 -output-directory=output #{@name}.tex"
      sh "platex -kanji=utf8 -output-directory=output #{@name}.tex"
    end
  end

  task :tex =>[:tex1,:bibtex]

  desc "compile tex files as pdf"
  task :pdf =>[:tex] do
    sh "dvipdfmx -o output/#{@name}.pdf output/#{@name}.dvi"
  end

  task :open =>[:setup] do
    if(RUBY_PLATFORM.downcase =~ /mswin(?!ce)|mingw|cygwin|bccwin/) then
      sh "output/#{@name}.pdf"
    else
      sh "open output/#{@name}.pdf"
    end
  end

  desc "do all compiling task"
  task :all =>[:setup,:tex1,:bibtex,:pdf,:open]

  desc "cleanup output directory"
  task :cleanup do
    sh "rm -r output/*"
  end
end