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: 
Mozilla kind-of-sort-of-not-really supports this with it's CSS `calc()` function.

This example shamelessly stolen (with attribution!) from [Ajaxian](http://ajaxian.com/archives/css-calc-in-the-house)

```
/*
* Two divs aligned, split up by a 1em margin
*/
#a {
  width:75%;
  margin-right: 1em;
}
#b {
  width: -moz-calc(25% - 1em);
}

```

It's not cross-browser, and it's probably only barely supported by even bleeding-edge versions of Firefox, but there's at least being progress made in that direction.
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;
}

```