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25 lines
867 B
Markdown
25 lines
867 B
Markdown
# ErrorKind to the rescue
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To cope with different kind of errors, we introduce the kind of an error `Func1ErrorKind` with an enum.
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Because we derive `Debug` and implement `Display` our `Func1ErrorKind` enum, this enum can be used as
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a `std::error::Error`.
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Not using `String` errors anymore, the `cherr!()` macro seen in the beginning of
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the tutorial has to be used again.
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Only returning `Func1ErrorKind` in `func1()` now let us get rid of `Result<(), Box<Error>>` and we can
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use `ChainResult<(), Func1ErrorKind>`.
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In `main` we can now directly use the methods of `ChainError<T>` without downcasting the error first.
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Also a nice `match` on `ChainError<T>.kind()` is now possible, which returns `&T`, meaning
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`&Func1ErrorKind` here.
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~~~rust
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{{#include ../examples/tutorial10.rs}}
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# #[allow(dead_code)]
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# mod chainerror {
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{{#includecomment ../src/lib.rs}}
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# }
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~~~ |