Question: I'm looking for a way to do something like this:

```
// style.css
@def borderSize '2px';

.style {
  width: borderSize + 2;
  height: borderSize + 2;
}

```

where the width and height attributes would end up having values of 4px.

Answer: 
You could also calculate in your provider method, if you put a parameter in the function:

```
@eval baseFontSize com.myexample.CssSettingsProvider.getBaseFontSize(0)+"pt";

@eval baseFontSize_plus_1 com.myexample.CssSettingsProvider.getBaseFontSize(1)+"pt";

```

`com.myexample.CssSettingsProvider` would look like this:

```
public static int getBaseFontSize(int sizeToAdd) {
    if (true) {
        return 9 + sizeToAdd;
    }
    return baseFontSize;
}

```
I would also love somehting like that, but it's not possible.
Even in CSS 3 their is nothing planned like this.

If you really want to make something like that, one possibility is to use
php and configure your webserver, so that .css files are parsed by php.

So you could do something like

```
<?
  $borderSize = 2;
?>

.style {
  width: <? borderSize+2 ?>px;
  height: <? borderSize+2 ?>px;
}

```

But as this is no 'standard' way, i think its better to not do it.