Sass で sprintf。compass なら、config.rb に sprintf.rb の内容を書いておくと使える。

sample.scss

$tmp: "";
.sample1:after{
  $tmp: sprintf("%02d,%02d", 1, 2);
  content: "#{$tmp}";
}
// 結果：content: "01,02";

$tmp: "";
.sample1:after{
  $tmp: sprintf("%.5s", foobar);
  content: "#{$tmp}";
}
// 結果：content: "fooba";

sprintf.rb

require "sass"

module WakuworksFunctions
  def sprintf(format, *args)
    assert_type format, :String
    assert_type args, :Array
    Sass::Script::String.new(format.value%args)
  end
end

module Sass::Script::Functions
  include WakuworksFunctions
end