diff --git a/exercises/23_conversions/try_from_into.rs b/exercises/23_conversions/try_from_into.rs index da45e5a4..f3ae80a9 100644 --- a/exercises/23_conversions/try_from_into.rs +++ b/exercises/23_conversions/try_from_into.rs @@ -1,9 +1,10 @@ -// TryFrom is a simple and safe type conversion that may fail in a controlled -// way under some circumstances. Basically, this is the same as From. The main -// difference is that this should return a Result type instead of the target -// type itself. You can read more about it at +// `TryFrom` is a simple and safe type conversion that may fail in a controlled +// way under some circumstances. Basically, this is the same as `From`. The main +// difference is that this should return a `Result` type instead of the target +// type itself. You can read more about it in the documentation: // https://doc.rust-lang.org/std/convert/trait.TryFrom.html +#![allow(clippy::useless_vec)] use std::convert::{TryFrom, TryInto}; #[derive(Debug, PartialEq)] @@ -13,7 +14,7 @@ struct Color { blue: u8, } -// We will use this error type for these `TryFrom` conversions. +// We will use this error type for the `TryFrom` conversions. #[derive(Debug, PartialEq)] enum IntoColorError { // Incorrect length of slice @@ -22,78 +23,67 @@ enum IntoColorError { IntConversion, } -// Your task is to complete this implementation and return an Ok result of inner -// type Color. You need to create an implementation for a tuple of three -// integers, an array of three integers, and a slice of integers. -// -// Note that the implementation for tuple and array will be checked at compile -// time, but the slice implementation needs to check the slice length! Also note -// that correct RGB color values must be integers in the 0..=255 range. - -// Tuple implementation +// TODO: Tuple implementation. +// Correct RGB color values must be integers in the 0..=255 range. impl TryFrom<(i16, i16, i16)> for Color { type Error = IntoColorError; - fn try_from(tuple: (i16, i16, i16)) -> Result { - } + + fn try_from(tuple: (i16, i16, i16)) -> Result {} } -// Array implementation +// TODO: Array implementation. impl TryFrom<[i16; 3]> for Color { type Error = IntoColorError; - fn try_from(arr: [i16; 3]) -> Result { - } + + fn try_from(arr: [i16; 3]) -> Result {} } -// Slice implementation +// TODO: Slice implementation. +// This implementation needs to check the slice length. impl TryFrom<&[i16]> for Color { type Error = IntoColorError; - fn try_from(slice: &[i16]) -> Result { - } + + fn try_from(slice: &[i16]) -> Result {} } fn main() { - // Use the `try_from` function + // Using the `try_from` function. let c1 = Color::try_from((183, 65, 14)); - println!("{:?}", c1); + println!("{c1:?}"); - // Since TryFrom is implemented for Color, we should be able to use TryInto + // Since `TryFrom` is implemented for `Color`, we can use `TryInto`. let c2: Result = [183, 65, 14].try_into(); - println!("{:?}", c2); + println!("{c2:?}"); let v = vec![183, 65, 14]; - // With slice we should use `try_from` function + // With slice we should use the `try_from` function let c3 = Color::try_from(&v[..]); - println!("{:?}", c3); - // or take slice within round brackets and use TryInto + println!("{c3:?}"); + // or put the slice within round brackets and use `try_into`. let c4: Result = (&v[..]).try_into(); - println!("{:?}", c4); + println!("{c4:?}"); } #[cfg(test)] mod tests { use super::*; + use IntoColorError::*; #[test] fn test_tuple_out_of_range_positive() { - assert_eq!( - Color::try_from((256, 1000, 10000)), - Err(IntoColorError::IntConversion) - ); + assert_eq!(Color::try_from((256, 1000, 10000)), Err(IntConversion)); } + #[test] fn test_tuple_out_of_range_negative() { - assert_eq!( - Color::try_from((-1, -10, -256)), - Err(IntoColorError::IntConversion) - ); + assert_eq!(Color::try_from((-1, -10, -256)), Err(IntConversion)); } + #[test] fn test_tuple_sum() { - assert_eq!( - Color::try_from((-1, 255, 255)), - Err(IntoColorError::IntConversion) - ); + assert_eq!(Color::try_from((-1, 255, 255)), Err(IntConversion)); } + #[test] fn test_tuple_correct() { let c: Result = (183, 65, 14).try_into(); @@ -103,25 +93,29 @@ mod tests { Color { red: 183, green: 65, - blue: 14 + blue: 14, } ); } + #[test] fn test_array_out_of_range_positive() { let c: Result = [1000, 10000, 256].try_into(); - assert_eq!(c, Err(IntoColorError::IntConversion)); + assert_eq!(c, Err(IntConversion)); } + #[test] fn test_array_out_of_range_negative() { let c: Result = [-10, -256, -1].try_into(); - assert_eq!(c, Err(IntoColorError::IntConversion)); + assert_eq!(c, Err(IntConversion)); } + #[test] fn test_array_sum() { let c: Result = [-1, 255, 255].try_into(); - assert_eq!(c, Err(IntoColorError::IntConversion)); + assert_eq!(c, Err(IntConversion)); } + #[test] fn test_array_correct() { let c: Result = [183, 65, 14].try_into(); @@ -135,30 +129,25 @@ mod tests { } ); } + #[test] fn test_slice_out_of_range_positive() { let arr = [10000, 256, 1000]; - assert_eq!( - Color::try_from(&arr[..]), - Err(IntoColorError::IntConversion) - ); + assert_eq!(Color::try_from(&arr[..]), Err(IntConversion)); } + #[test] fn test_slice_out_of_range_negative() { let arr = [-256, -1, -10]; - assert_eq!( - Color::try_from(&arr[..]), - Err(IntoColorError::IntConversion) - ); + assert_eq!(Color::try_from(&arr[..]), Err(IntConversion)); } + #[test] fn test_slice_sum() { let arr = [-1, 255, 255]; - assert_eq!( - Color::try_from(&arr[..]), - Err(IntoColorError::IntConversion) - ); + assert_eq!(Color::try_from(&arr[..]), Err(IntConversion)); } + #[test] fn test_slice_correct() { let v = vec![183, 65, 14]; @@ -169,18 +158,20 @@ mod tests { Color { red: 183, green: 65, - blue: 14 + blue: 14, } ); } + #[test] fn test_slice_excess_length() { let v = vec![0, 0, 0, 0]; - assert_eq!(Color::try_from(&v[..]), Err(IntoColorError::BadLen)); + assert_eq!(Color::try_from(&v[..]), Err(BadLen)); } + #[test] fn test_slice_insufficient_length() { let v = vec![0, 0]; - assert_eq!(Color::try_from(&v[..]), Err(IntoColorError::BadLen)); + assert_eq!(Color::try_from(&v[..]), Err(BadLen)); } } diff --git a/rustlings-macros/info.toml b/rustlings-macros/info.toml index 4ef1a0a3..488fdacf 100644 --- a/rustlings-macros/info.toml +++ b/rustlings-macros/info.toml @@ -1197,21 +1197,8 @@ https://doc.rust-lang.org/stable/rust-by-example/error/multiple_error_types/reen name = "try_from_into" dir = "23_conversions" hint = """ -Follow the steps provided right before the `TryFrom` implementation. -You can also use the example at -https://doc.rust-lang.org/std/convert/trait.TryFrom.html - -Is there an implementation of `TryFrom` in the standard library that -can both do the required integer conversion and check the range of the input? - -Another hint: Look at the test cases to see which error variants to return. - -Yet another hint: You can use the `map_err` or `or` methods of `Result` to -convert errors. - -Yet another hint: If you would like to propagate errors by using the `?` -operator in your solution, you might want to look at -https://doc.rust-lang.org/stable/rust-by-example/error/multiple_error_types/reenter_question_mark.html +Is there an implementation of `TryFrom` in the standard library that can both do +the required integer conversion and check the range of the input? Challenge: Can you make the `TryFrom` implementations generic over many integer types?""" diff --git a/solutions/23_conversions/try_from_into.rs b/solutions/23_conversions/try_from_into.rs index 4e181989..acb7721d 100644 --- a/solutions/23_conversions/try_from_into.rs +++ b/solutions/23_conversions/try_from_into.rs @@ -1 +1,192 @@ -// Solutions will be available before the stable release. Thank you for testing the beta version 🥰 +// `TryFrom` is a simple and safe type conversion that may fail in a controlled +// way under some circumstances. Basically, this is the same as `From`. The main +// difference is that this should return a `Result` type instead of the target +// type itself. You can read more about it in the documentation: +// https://doc.rust-lang.org/std/convert/trait.TryFrom.html + +use std::convert::{TryFrom, TryInto}; + +#[derive(Debug, PartialEq)] +struct Color { + red: u8, + green: u8, + blue: u8, +} + +// We will use this error type for the `TryFrom` conversions. +#[derive(Debug, PartialEq)] +enum IntoColorError { + // Incorrect length of slice + BadLen, + // Integer conversion error + IntConversion, +} + +impl TryFrom<(i16, i16, i16)> for Color { + type Error = IntoColorError; + + fn try_from(tuple: (i16, i16, i16)) -> Result { + let (Ok(red), Ok(green), Ok(blue)) = ( + u8::try_from(tuple.0), + u8::try_from(tuple.1), + u8::try_from(tuple.2), + ) else { + return Err(IntoColorError::IntConversion); + }; + + Ok(Self { red, green, blue }) + } +} + +impl TryFrom<[i16; 3]> for Color { + type Error = IntoColorError; + + fn try_from(arr: [i16; 3]) -> Result { + // Reuse the implementation for a tuple. + Self::try_from((arr[0], arr[1], arr[2])) + } +} + +impl TryFrom<&[i16]> for Color { + type Error = IntoColorError; + + fn try_from(slice: &[i16]) -> Result { + // Check the length. + if slice.len() != 3 { + return Err(IntoColorError::BadLen); + } + + // Reuse the implementation for a tuple. + Self::try_from((slice[0], slice[1], slice[2])) + } +} + +fn main() { + // Using the `try_from` function. + let c1 = Color::try_from((183, 65, 14)); + println!("{c1:?}"); + + // Since `TryFrom` is implemented for `Color`, we can use `TryInto`. + let c2: Result = [183, 65, 14].try_into(); + println!("{c2:?}"); + + let v = vec![183, 65, 14]; + // With slice we should use the `try_from` function + let c3 = Color::try_from(&v[..]); + println!("{c3:?}"); + // or put the slice within round brackets and use `try_into`. + let c4: Result = (&v[..]).try_into(); + println!("{c4:?}"); +} + +#[cfg(test)] +mod tests { + use super::*; + use IntoColorError::*; + + #[test] + fn test_tuple_out_of_range_positive() { + assert_eq!(Color::try_from((256, 1000, 10000)), Err(IntConversion)); + } + + #[test] + fn test_tuple_out_of_range_negative() { + assert_eq!(Color::try_from((-1, -10, -256)), Err(IntConversion)); + } + + #[test] + fn test_tuple_sum() { + assert_eq!(Color::try_from((-1, 255, 255)), Err(IntConversion)); + } + + #[test] + fn test_tuple_correct() { + let c: Result = (183, 65, 14).try_into(); + assert!(c.is_ok()); + assert_eq!( + c.unwrap(), + Color { + red: 183, + green: 65, + blue: 14, + } + ); + } + + #[test] + fn test_array_out_of_range_positive() { + let c: Result = [1000, 10000, 256].try_into(); + assert_eq!(c, Err(IntConversion)); + } + + #[test] + fn test_array_out_of_range_negative() { + let c: Result = [-10, -256, -1].try_into(); + assert_eq!(c, Err(IntConversion)); + } + + #[test] + fn test_array_sum() { + let c: Result = [-1, 255, 255].try_into(); + assert_eq!(c, Err(IntConversion)); + } + + #[test] + fn test_array_correct() { + let c: Result = [183, 65, 14].try_into(); + assert!(c.is_ok()); + assert_eq!( + c.unwrap(), + Color { + red: 183, + green: 65, + blue: 14 + } + ); + } + + #[test] + fn test_slice_out_of_range_positive() { + let arr = [10000, 256, 1000]; + assert_eq!(Color::try_from(&arr[..]), Err(IntConversion)); + } + + #[test] + fn test_slice_out_of_range_negative() { + let arr = [-256, -1, -10]; + assert_eq!(Color::try_from(&arr[..]), Err(IntConversion)); + } + + #[test] + fn test_slice_sum() { + let arr = [-1, 255, 255]; + assert_eq!(Color::try_from(&arr[..]), Err(IntConversion)); + } + + #[test] + fn test_slice_correct() { + let v = vec![183, 65, 14]; + let c: Result = Color::try_from(&v[..]); + assert!(c.is_ok()); + assert_eq!( + c.unwrap(), + Color { + red: 183, + green: 65, + blue: 14, + } + ); + } + + #[test] + fn test_slice_excess_length() { + let v = vec![0, 0, 0, 0]; + assert_eq!(Color::try_from(&v[..]), Err(BadLen)); + } + + #[test] + fn test_slice_insufficient_length() { + let v = vec![0, 0]; + assert_eq!(Color::try_from(&v[..]), Err(BadLen)); + } +}