Implement TryFrom in Rust
Rust interview exercise on Traits & Generics, difficulty 3 of 3. Solve it in the editor beside a worked example; the tests run the moment you do.
Implement TryFrom<&str> for Rgb so "#ff8000" becomes Rgb { r: 255, g: 128, b: 0 }. Errors are Strings, checked in this order: "missing #", then "expected 6 hex digits" (wrong length), then "invalid hex digit". Implementing TryFrom also makes "#000000".try_into() work.
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