treehouse/content/programming/blog/try-is-not-the-only-option.tree

%% title = "`?` is not the only option"

% id = "01J4J6400Q4MWF2QPGX3P9Q2WQ"
- if there's one thing I learned from Go...

```rust
let mut list = WalkList::new(args);

let condition = list.expect_arg(c, src, "missing `if` condition");
let if_true = list.expect_arg(c, src, "missing `if` true branch");
let if_false = list.expect_arg(c, src, "missing `if` false branch");
list.expect_nil(c, src, "extra arguments after `if` false branch");

if !list.ok {
    return Ok(());
}
```

...it's that `?` is not the only option.