[Feature Request] Alternatives with conditional elements in the list

Is it possible to add a syntax so alternatives can have flexible number of elements?

For example:

```{~Heads|Tails}```
can be like:
```{~Heads|{not john_cheat}Tails}```

To complete the story logic that when someone cheated, the coin always show heads.

When the list gets long, this syntax can be very handy. I don't know other ways to do similar things.

EDIT:
For example:
```I eat the {~!apple|{get_banana}banana|{get_chocolate}chocolate|{get_tomato}tomato|{get_cake}cake} in my pocket.```