Tempdir function

---

examples/filesystem/tempdir_function.cr

require "file_utils"

tempdir(cleanup: true) do |tmp_dir|
  puts tmp_dir
  path = Path.new(tmp_dir, "welcome.txt")
  File.write(path, "Hello World")
end

def tempdir(cleanup = true)
  tmp_dir = File.tempname
  begin
    FileUtils.mkdir(tmp_dir)
    yield tmp_dir
  ensure
    if cleanup
      FileUtils.rm_rf(tmp_dir)
    end
  end
end