mirror of
https://github.com/rust-lang/rustlings.git
synced 2024-12-14 11:22:55 +02:00
137 lines
3.8 KiB
Rust
137 lines
3.8 KiB
Rust
// 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
|
|
use std::convert::{TryInto, TryFrom};
|
|
|
|
#[derive(Debug)]
|
|
struct Color {
|
|
red: u8,
|
|
green: u8,
|
|
blue: u8,
|
|
}
|
|
|
|
// I AM NOT DONE
|
|
|
|
// Your task is to complete this implementation
|
|
// and return an Ok result of inner type Color.
|
|
// You need create implementation for a tuple of three integer,
|
|
// an array of three integer and slice of integer.
|
|
//
|
|
// Note, that implementation for tuple and array will be checked at compile-time,
|
|
// but slice implementation need check slice length!
|
|
// Also note, that chunk of correct rgb color must be integer in range 0..=255.
|
|
|
|
// Tuple implementation
|
|
impl TryFrom<(i16, i16, i16)> for Color {
|
|
type Error = String;
|
|
fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> {
|
|
}
|
|
}
|
|
|
|
// Array implementation
|
|
impl TryFrom<[i16; 3]> for Color {
|
|
type Error = String;
|
|
fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> {
|
|
}
|
|
}
|
|
|
|
// Slice implementation
|
|
impl TryFrom<&[i16]> for Color {
|
|
type Error = String;
|
|
fn try_from(slice: &[i16]) -> Result<Self, Self::Error> {
|
|
}
|
|
}
|
|
|
|
fn main() {
|
|
// Use the `from` function
|
|
let c1 = Color::try_from((183, 65, 14));
|
|
println!("{:?}", c1);
|
|
|
|
// Since From is implemented for Color, we should be able to use Into
|
|
let c2: Result<Color, _> = [183, 65, 14].try_into();
|
|
println!("{:?}", c2);
|
|
|
|
let v = vec![183, 65, 14];
|
|
// With slice we should use `from` function
|
|
let c3 = Color::try_from(&v[..]);
|
|
println!("{:?}", c3);
|
|
// or take slice within round brackets and use Into
|
|
let c4: Result<Color, _> = (&v[..]).try_into();
|
|
println!("{:?}", c4);
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod tests {
|
|
use super::*;
|
|
|
|
#[test]
|
|
#[should_panic]
|
|
fn test_tuple_out_of_range_positive() {
|
|
let _ = Color::try_from((256, 1000, 10000)).unwrap();
|
|
}
|
|
#[test]
|
|
#[should_panic]
|
|
fn test_tuple_out_of_range_negative() {
|
|
let _ = Color::try_from((-1, -10, -256)).unwrap();
|
|
}
|
|
#[test]
|
|
fn test_tuple_correct() {
|
|
let c: Color = (183, 65, 14).try_into().unwrap();
|
|
assert_eq!(c.red, 183);
|
|
assert_eq!(c.green, 65);
|
|
assert_eq!(c.blue, 14);
|
|
}
|
|
|
|
#[test]
|
|
#[should_panic]
|
|
fn test_array_out_of_range_positive() {
|
|
let _: Color = [1000, 10000, 256].try_into().unwrap();
|
|
}
|
|
#[test]
|
|
#[should_panic]
|
|
fn test_array_out_of_range_negative() {
|
|
let _: Color = [-10, -256, -1].try_into().unwrap();
|
|
}
|
|
#[test]
|
|
fn test_array_correct() {
|
|
let c: Color = [183, 65, 14].try_into().unwrap();
|
|
assert_eq!(c.red, 183);
|
|
assert_eq!(c.green, 65);
|
|
assert_eq!(c.blue, 14);
|
|
}
|
|
|
|
#[test]
|
|
#[should_panic]
|
|
fn test_slice_out_of_range_positive() {
|
|
let arr = [10000, 256, 1000];
|
|
let _ = Color::try_from(&arr[..]).unwrap();
|
|
}
|
|
#[test]
|
|
#[should_panic]
|
|
fn test_slice_out_of_range_negative() {
|
|
let arr = [-256, -1, -10];
|
|
let _ = Color::try_from(&arr[..]).unwrap();
|
|
}
|
|
#[test]
|
|
fn test_slice_correct() {
|
|
let v = vec![183, 65, 14];
|
|
let c = Color::try_from(&v[..]).unwrap();
|
|
assert_eq!(c.red, 183);
|
|
assert_eq!(c.green, 65);
|
|
assert_eq!(c.blue, 14);
|
|
}
|
|
#[test]
|
|
#[should_panic]
|
|
fn test_slice_excess_length() {
|
|
let v = vec![0, 0, 0, 0];
|
|
let _ = Color::try_from(&v[..]).unwrap();
|
|
}
|
|
#[test]
|
|
#[should_panic]
|
|
fn test_slice_insufficient_length() {
|
|
let v = vec![0, 0];
|
|
let _ = Color::try_from(&v[..]).unwrap();
|
|
}
|
|
}
|