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32 lines
851 B
Markdown
32 lines
851 B
Markdown
# Finding an Error cause
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To distinguish the errors occurring in various places, we can define named string errors with the
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"new type" pattern.
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~~~rust,ignore
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chainerror::str_context!(Func2Error);
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chainerror::str_context!(Func1Error);
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~~~
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Instead of `chainerror::Error<String>` we now have `struct Func1Error(String)` and `chainerror::Error<Func1Error>`.
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In the `main` function you can see, how we can match the different errors.
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Also see:
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~~~rust,ignore
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if let Some(f2err) = f1err.find_chain_cause::<Func2Error>() {
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~~~
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as a shortcut to
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~~~rust,ignore
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if let Some(f2err) = f1err.find_cause::<chainerror::Error<Func2Error>>() {
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~~~
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hiding the `chainerror::Error<T>` implementation detail.
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~~~rust
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{{#include ../examples/tutorial8.rs}}
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# #[allow(dead_code)]
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# mod chainerror {
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{{#rustdoc_include ../src/lib.rs:-1}}
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# }
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~~~
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