I think the `error` function has an undefined return value, so I won't depend on that (it might change in the future and break this seeminly unrelated code).

The first example looks interesting, but unfortunately I don't think Ruby has a way to group statements like that:

```
(string):2:18: error: unexpected token kDO
  tokens.any? or do
                 ^^
Parser::SyntaxError: unexpected token kDO
```

Maybe something like this:

``` Ruby
def handle?
  tokens.any? || (error "..." && false)
end
```

At that point I think I prefer the current implementation, though.