38 lines
972 B
Rust
38 lines
972 B
Rust
use crate::*;
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fn sum_of(values: Vec<i32>) -> Result<Outcome, FailedTo> {
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if values.is_empty() {
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return Ok(Outcome::Scalar(0));
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}
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let mut ret = Ok(Outcome::Scalar(0));
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for value in values {
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ret = ret.and_then(|outcome: Outcome| match outcome {
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Outcome::List(_) => Err(FailedTo::ProcessInput),
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Outcome::Scalar(acc) => acc
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.checked_add(value)
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.map(|new_acc: i32| Outcome::Scalar(new_acc))
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.ok_or(FailedTo::SumValues),
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})
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}
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ret
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}
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impl Outcome {
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pub fn sum(self) -> Result<Outcome, FailedTo> {
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match self {
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Outcome::Scalar(value) => Ok(Outcome::Scalar(value)),
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Outcome::List(values) => sum_of(values),
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}
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}
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}
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#[cfg(test)]
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mod unit_tests {
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use super::*;
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#[test]
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fn check_sum() {
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let outcome = Handful::grab(5, 1).roll().sum();
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assert_eq!(outcome, Ok(Outcome::Scalar(5)));
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}
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}
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