What is this unwrap thing: sometimes it's unwrap sometimes it's unwrap_or

Question

Note The specifics in this question regarding read_line and ~str pertain to a pre-1.0 version of Rust. The general concepts

Answer 1

Note The specifics in this answer regarding read_line and ~str pertain to a pre-1.0 version of Rust. The general concepts about unwrap and unwrap_or remain relevant.

Because read_line might fail it returns Option<~str>. To get the value out you can use pattern matching or one of the unwrap methods.

The difference between unwrap and unwrap_or is that unwrap will fail if there is no value (None) but unwrap_or will return the specified default ("nothing" in this case)