In the world of Hai:Hai has a die roller now. Check out the formatting page for the notation. It's basically [ ROLL ] 1d6 [ /ROLL ] or [ ROLL 1d6 ] (without the spaces).
It supports XdY, XdF (Fudge/Fate dice), and Xd% (percentile). And you can add/subtract bonuses (XdY+Z), so all of these are valid:
4d8e (8's "explode" and are rolled again)