mirror of https://github.com/sharkdp/bat.git
28 lines
775 B
Rust
28 lines
775 B
Rust
/// Helper function that might appear in Rust stable at some point
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/// (https://doc.rust-lang.org/stable/std/option/enum.Option.html#method.transpose)
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pub fn transpose<T, E>(opt: Option<Result<T, E>>) -> Result<Option<T>, E> {
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opt.map_or(Ok(None), |res| res.map(Some))
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}
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#[cfg(test)]
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mod tests {
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use super::transpose;
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#[derive(Debug, PartialEq)]
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struct TestError;
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type TestResult<T> = Result<T, TestError>;
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#[test]
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fn basic() {
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let a: Option<TestResult<i32>> = Some(Ok(2));
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assert_eq!(Ok(Some(2)), transpose(a));
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let b: Option<TestResult<i32>> = Some(Err(TestError));
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assert_eq!(Err(TestError), transpose(b));
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let c: Option<TestResult<i32>> = None;
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assert_eq!(Ok(None), transpose(c));
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}
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}
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