roll should be able to take some deterministic phrases

[notbenh]

Ideally I want to do something silly like:

> roll 2d20 if < 5 then you die in a fire if < 20 then you eat a goat else you wear a hat
d20: 7
d20: 8
  group total: 15 average: 7.5 min: 1 max: 8

roll total: 15

OUTCOME: you eat a goat