body
      foo = 'bar1_bar2_bar3'
      for i in split('_', foo)
        foo i

is still

    body {
      foo: bar1;
      foo: bar2;
      foo: bar3;
    }

The type of `foo` (string) is not preserved. It should be

    body {
      foo: 'bar1';
      foo: 'bar2';
      foo: 'bar3a';
    }