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Diffstat (limited to 'exercises/advanced_errors/advanced_errs1.rs')
| -rw-r--r-- | exercises/advanced_errors/advanced_errs1.rs | 98 |
1 files changed, 0 insertions, 98 deletions
diff --git a/exercises/advanced_errors/advanced_errs1.rs b/exercises/advanced_errors/advanced_errs1.rs deleted file mode 100644 index 4bc7b63..0000000 --- a/exercises/advanced_errors/advanced_errs1.rs +++ /dev/null @@ -1,98 +0,0 @@ -// advanced_errs1.rs - -// Remember back in errors6, we had multiple mapping functions so that we -// could translate lower-level errors into our custom error type using -// `map_err()`? What if we could use the `?` operator directly instead? - -// Make this code compile! Execute `rustlings hint advanced_errs1` for -// hints :) - -// I AM NOT DONE - -use std::num::ParseIntError; -use std::str::FromStr; - -// This is a custom error type that we will be using in the `FromStr` -// implementation. -#[derive(PartialEq, Debug)] -enum ParsePosNonzeroError { - Creation(CreationError), - ParseInt(ParseIntError), -} - -impl From<CreationError> for ParsePosNonzeroError { - fn from(e: CreationError) -> Self { - // TODO: complete this implementation so that the `?` operator will - // work for `CreationError` - } -} - -// TODO: implement another instance of the `From` trait here so that the -// `?` operator will work in the other place in the `FromStr` -// implementation below. - -// Don't change anything below this line. - -impl FromStr for PositiveNonzeroInteger { - type Err = ParsePosNonzeroError; - fn from_str(s: &str) -> Result<PositiveNonzeroInteger, Self::Err> { - let x: i64 = s.parse()?; - Ok(PositiveNonzeroInteger::new(x)?) - } -} - -#[derive(PartialEq, Debug)] -struct PositiveNonzeroInteger(u64); - -#[derive(PartialEq, Debug)] -enum CreationError { - Negative, - Zero, -} - -impl PositiveNonzeroInteger { - fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> { - match value { - x if x < 0 => Err(CreationError::Negative), - x if x == 0 => Err(CreationError::Zero), - x => Ok(PositiveNonzeroInteger(x as u64)), - } - } -} - -#[cfg(test)] -mod test { - use super::*; - - #[test] - fn test_parse_error() { - // We can't construct a ParseIntError, so we have to pattern match. - assert!(matches!( - PositiveNonzeroInteger::from_str("not a number"), - Err(ParsePosNonzeroError::ParseInt(_)) - )); - } - - #[test] - fn test_negative() { - assert_eq!( - PositiveNonzeroInteger::from_str("-555"), - Err(ParsePosNonzeroError::Creation(CreationError::Negative)) - ); - } - - #[test] - fn test_zero() { - assert_eq!( - PositiveNonzeroInteger::from_str("0"), - Err(ParsePosNonzeroError::Creation(CreationError::Zero)) - ); - } - - #[test] - fn test_positive() { - let x = PositiveNonzeroInteger::new(42); - assert!(x.is_ok()); - assert_eq!(PositiveNonzeroInteger::from_str("42"), Ok(x.unwrap())); - } -} |
