While playing with stylus (v0.31), i noticed that you can name your parameters when calling a function:
/* Define */
myMixin(color, font)
background-color color
font-family font
/* Use */
body
myMixin(color: green, font: helvetica)
This is great for mixins with many parameters and you don’t want your users to memorize the order of which they need to be defined.
However, I didn’t see this in the documentation. Hopefully this feature will stay in for future releases.