rustlings/exercises/conversions/try_from_into.rs

191 lines
5.2 KiB
Rust
Raw Normal View History

// 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
2022-07-15 10:49:49 +00:00
// Execute `rustlings hint try_from_into` or use the `hint` watch subcommand for a hint.
2022-07-15 10:34:10 +00:00
2020-08-10 14:24:21 +00:00
use std::convert::{TryFrom, TryInto};
#[derive(Debug, PartialEq)]
2020-05-15 21:02:57 +00:00
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
2020-05-15 21:02:57 +00:00
// Your task is to complete this implementation
2020-05-15 21:02:57 +00:00
// 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.
2020-05-15 21:02:57 +00:00
// Tuple implementation
impl TryFrom<(i16, i16, i16)> for Color {
type Error = IntoColorError;
fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> {
}
2020-05-15 21:02:57 +00:00
}
// Array implementation
impl TryFrom<[i16; 3]> for Color {
type Error = IntoColorError;
fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> {
}
2020-05-15 21:02:57 +00:00
}
// Slice implementation
impl TryFrom<&[i16]> for Color {
type Error = IntoColorError;
fn try_from(slice: &[i16]) -> Result<Self, Self::Error> {
}
}
fn main() {
2022-07-15 12:08:51 +00:00
// Use the `try_from` function
2020-05-15 21:02:57 +00:00
let c1 = Color::try_from((183, 65, 14));
println!("{:?}", c1);
// Since TryFrom is implemented for Color, we should be able to use TryInto
2020-05-15 21:02:57 +00:00
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
2020-05-15 21:02:57 +00:00
let c3 = Color::try_from(&v[..]);
println!("{:?}", c3);
// or take slice within round brackets and use TryInto
2020-05-15 21:02:57 +00:00
let c4: Result<Color, _> = (&v[..]).try_into();
println!("{:?}", c4);
}
#[cfg(test)]
mod tests {
use super::*;
2020-05-15 21:02:57 +00:00
#[test]
2020-05-15 21:02:57 +00:00
fn test_tuple_out_of_range_positive() {
assert_eq!(
Color::try_from((256, 1000, 10000)),
Err(IntoColorError::IntConversion)
);
}
#[test]
2020-05-15 21:02:57 +00:00
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]
2020-05-15 21:02:57 +00:00
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
}
);
}
2020-05-03 00:41:11 +00:00
#[test]
2020-05-15 21:02:57 +00:00
fn test_array_out_of_range_positive() {
let c: Result<Color, _> = [1000, 10000, 256].try_into();
assert_eq!(c, Err(IntoColorError::IntConversion));
2020-05-03 00:41:11 +00:00
}
#[test]
2020-05-15 21:02:57 +00:00
fn test_array_out_of_range_negative() {
let c: Result<Color, _> = [-10, -256, -1].try_into();
assert_eq!(c, Err(IntoColorError::IntConversion));
2020-05-15 21:02:57 +00:00
}
#[test]
fn test_array_sum() {
let c: Result<Color, _> = [-1, 255, 255].try_into();
assert_eq!(c, Err(IntoColorError::IntConversion));
}
#[test]
2020-05-15 21:02:57 +00:00
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
}
);
2020-05-03 00:41:11 +00:00
}
#[test]
2020-05-15 21:02:57 +00:00
fn test_slice_out_of_range_positive() {
let arr = [10000, 256, 1000];
assert_eq!(
Color::try_from(&arr[..]),
Err(IntoColorError::IntConversion)
);
2020-05-03 00:41:11 +00:00
}
#[test]
2020-05-15 21:02:57 +00:00
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)
);
2020-05-15 21:02:57 +00:00
}
#[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
}
);
2020-05-03 00:41:11 +00:00
}
#[test]
2020-05-15 21:02:57 +00:00
fn test_slice_excess_length() {
let v = vec![0, 0, 0, 0];
assert_eq!(Color::try_from(&v[..]), Err(IntoColorError::BadLen));
2020-05-03 00:41:11 +00:00
}
#[test]
fn test_slice_insufficient_length() {
let v = vec![0, 0];
assert_eq!(Color::try_from(&v[..]), Err(IntoColorError::BadLen));
}
2020-05-15 21:02:57 +00:00
}