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Diffstat (limited to 'exercises/23_conversions/try_from_into.rs')
| -rw-r--r-- | exercises/23_conversions/try_from_into.rs | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/exercises/23_conversions/try_from_into.rs b/exercises/23_conversions/try_from_into.rs new file mode 100644 index 0000000..32d6ef3 --- /dev/null +++ b/exercises/23_conversions/try_from_into.rs @@ -0,0 +1,193 @@ +// try_from_into.rs +// +// 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 +// https://doc.rust-lang.org/std/convert/trait.TryFrom.html +// +// Execute `rustlings hint try_from_into` or use the `hint` watch subcommand for +// a hint. + +use std::convert::{TryFrom, TryInto}; + +#[derive(Debug, PartialEq)] +struct Color { + red: u8, + green: u8, + blue: u8, +} + +// We will use this error type for these `TryFrom` conversions. +#[derive(Debug, PartialEq)] +enum IntoColorError { + // Incorrect length of slice + BadLen, + // Integer conversion error + IntConversion, +} + +// I AM NOT DONE + +// 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 +impl TryFrom<(i16, i16, i16)> for Color { + type Error = IntoColorError; + fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> { + } +} + +// Array implementation +impl TryFrom<[i16; 3]> for Color { + type Error = IntoColorError; + fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> { + } +} + +// Slice implementation +impl TryFrom<&[i16]> for Color { + type Error = IntoColorError; + fn try_from(slice: &[i16]) -> Result<Self, Self::Error> { + } +} + +fn main() { + // Use the `try_from` function + let c1 = Color::try_from((183, 65, 14)); + println!("{:?}", c1); + + // Since TryFrom is implemented for Color, we should be able to use TryInto + let c2: Result<Color, _> = [183, 65, 14].try_into(); + println!("{:?}", c2); + + let v = vec![183, 65, 14]; + // With slice we should use `try_from` function + let c3 = Color::try_from(&v[..]); + println!("{:?}", c3); + // or take slice within round brackets and use TryInto + let c4: Result<Color, _> = (&v[..]).try_into(); + println!("{:?}", c4); +} + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn test_tuple_out_of_range_positive() { + assert_eq!( + Color::try_from((256, 1000, 10000)), + Err(IntoColorError::IntConversion) + ); + } + #[test] + fn test_tuple_out_of_range_negative() { + assert_eq!( + Color::try_from((-1, -10, -256)), + Err(IntoColorError::IntConversion) + ); + } + #[test] + fn test_tuple_sum() { + assert_eq!( + Color::try_from((-1, 255, 255)), + Err(IntoColorError::IntConversion) + ); + } + #[test] + fn test_tuple_correct() { + let c: Result<Color, _> = (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<Color, _> = [1000, 10000, 256].try_into(); + assert_eq!(c, Err(IntoColorError::IntConversion)); + } + #[test] + fn test_array_out_of_range_negative() { + let c: Result<Color, _> = [-10, -256, -1].try_into(); + assert_eq!(c, Err(IntoColorError::IntConversion)); + } + #[test] + fn test_array_sum() { + let c: Result<Color, _> = [-1, 255, 255].try_into(); + assert_eq!(c, Err(IntoColorError::IntConversion)); + } + #[test] + fn test_array_correct() { + let c: Result<Color, _> = [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(IntoColorError::IntConversion) + ); + } + #[test] + fn test_slice_out_of_range_negative() { + let arr = [-256, -1, -10]; + assert_eq!( + Color::try_from(&arr[..]), + Err(IntoColorError::IntConversion) + ); + } + #[test] + fn test_slice_sum() { + let arr = [-1, 255, 255]; + assert_eq!( + Color::try_from(&arr[..]), + Err(IntoColorError::IntConversion) + ); + } + #[test] + fn test_slice_correct() { + let v = vec![183, 65, 14]; + let c: Result<Color, _> = 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(IntoColorError::BadLen)); + } + #[test] + fn test_slice_insufficient_length() { + let v = vec![0, 0]; + assert_eq!(Color::try_from(&v[..]), Err(IntoColorError::BadLen)); + } +} |
