diff options
Diffstat (limited to 'rustlings/exercises/23_conversions')
| -rw-r--r-- | rustlings/exercises/23_conversions/README.md | 23 | ||||
| -rw-r--r-- | rustlings/exercises/23_conversions/as_ref_mut.rs | 62 | ||||
| -rw-r--r-- | rustlings/exercises/23_conversions/from_into.rs | 130 | ||||
| -rw-r--r-- | rustlings/exercises/23_conversions/from_str.rs | 113 | ||||
| -rw-r--r-- | rustlings/exercises/23_conversions/try_from_into.rs | 177 | ||||
| -rw-r--r-- | rustlings/exercises/23_conversions/using_as.rs | 24 |
6 files changed, 0 insertions, 529 deletions
diff --git a/rustlings/exercises/23_conversions/README.md b/rustlings/exercises/23_conversions/README.md deleted file mode 100644 index 619a78c..0000000 --- a/rustlings/exercises/23_conversions/README.md +++ /dev/null @@ -1,23 +0,0 @@ -# Type conversions - -Rust offers a multitude of ways to convert a value of a given type into another type. - -The simplest form of type conversion is a type cast expression. It is denoted with the binary operator `as`. For instance, `println!("{}", 1 + 1.0);` would not compile, since `1` is an integer while `1.0` is a float. However, `println!("{}", 1 as f32 + 1.0)` should compile. The exercise [`using_as`](using_as.rs) tries to cover this. - -Rust also offers traits that facilitate type conversions upon implementation. These traits can be found under the [`convert`](https://doc.rust-lang.org/std/convert/index.html) module. -The traits are the following: - -- `From` and `Into` covered in [`from_into`](from_into.rs) -- `TryFrom` and `TryInto` covered in [`try_from_into`](try_from_into.rs) -- `AsRef` and `AsMut` covered in [`as_ref_mut`](as_ref_mut.rs) - -Furthermore, the `std::str` module offers a trait called [`FromStr`](https://doc.rust-lang.org/std/str/trait.FromStr.html) which helps with converting strings into target types via the `parse` method on strings. If properly implemented for a given type `Person`, then `let p: Person = "Mark,20".parse().unwrap()` should both compile and run without panicking. - -These should be the main ways ***within the standard library*** to convert data into your desired types. - -## Further information - -These are not directly covered in the book, but the standard library has a great documentation for it. - -- [conversions](https://doc.rust-lang.org/std/convert/index.html) -- [`FromStr` trait](https://doc.rust-lang.org/std/str/trait.FromStr.html) diff --git a/rustlings/exercises/23_conversions/as_ref_mut.rs b/rustlings/exercises/23_conversions/as_ref_mut.rs deleted file mode 100644 index d7892dd..0000000 --- a/rustlings/exercises/23_conversions/as_ref_mut.rs +++ /dev/null @@ -1,62 +0,0 @@ -// AsRef and AsMut allow for cheap reference-to-reference conversions. Read more -// about them at https://doc.rust-lang.org/std/convert/trait.AsRef.html and -// https://doc.rust-lang.org/std/convert/trait.AsMut.html, respectively. - -// Obtain the number of bytes (not characters) in the given argument -// (`.len()` returns the number of bytes in a string). -// TODO: Add the `AsRef` trait appropriately as a trait bound. -fn byte_counter<T>(arg: T) -> usize { - arg.as_ref().len() -} - -// Obtain the number of characters (not bytes) in the given argument. -// TODO: Add the `AsRef` trait appropriately as a trait bound. -fn char_counter<T>(arg: T) -> usize { - arg.as_ref().chars().count() -} - -// Squares a number using `as_mut()`. -// TODO: Add the appropriate trait bound. -fn num_sq<T>(arg: &mut T) { - // TODO: Implement the function body. -} - -fn main() { - // You can optionally experiment here. -} - -#[cfg(test)] -mod tests { - use super::*; - - #[test] - fn different_counts() { - let s = "Café au lait"; - assert_ne!(char_counter(s), byte_counter(s)); - } - - #[test] - fn same_counts() { - let s = "Cafe au lait"; - assert_eq!(char_counter(s), byte_counter(s)); - } - - #[test] - fn different_counts_using_string() { - let s = String::from("Café au lait"); - assert_ne!(char_counter(s.clone()), byte_counter(s)); - } - - #[test] - fn same_counts_using_string() { - let s = String::from("Cafe au lait"); - assert_eq!(char_counter(s.clone()), byte_counter(s)); - } - - #[test] - fn mut_box() { - let mut num: Box<u32> = Box::new(3); - num_sq(&mut num); - assert_eq!(*num, 9); - } -} diff --git a/rustlings/exercises/23_conversions/from_into.rs b/rustlings/exercises/23_conversions/from_into.rs deleted file mode 100644 index bc2783a..0000000 --- a/rustlings/exercises/23_conversions/from_into.rs +++ /dev/null @@ -1,130 +0,0 @@ -// The `From` trait is used for value-to-value conversions. If `From` is -// implemented, an implementation of `Into` is automatically provided. -// You can read more about it in the documentation: -// https://doc.rust-lang.org/std/convert/trait.From.html - -#[derive(Debug)] -struct Person { - name: String, - age: u8, -} - -// We implement the Default trait to use it as a fallback when the provided -// string is not convertible into a `Person` object. -impl Default for Person { - fn default() -> Self { - Self { - name: String::from("John"), - age: 30, - } - } -} - -// TODO: Complete this `From` implementation to be able to parse a `Person` -// out of a string in the form of "Mark,20". -// Note that you'll need to parse the age component into a `u8` with something -// like `"4".parse::<u8>()`. -// -// Steps: -// 1. Split the given string on the commas present in it. -// 2. If the split operation returns less or more than 2 elements, return the -// default of `Person`. -// 3. Use the first element from the split operation as the name. -// 4. If the name is empty, return the default of `Person`. -// 5. Parse the second element from the split operation into a `u8` as the age. -// 6. If parsing the age fails, return the default of `Person`. -impl From<&str> for Person { - fn from(s: &str) -> Self {} -} - -fn main() { - // Use the `from` function. - let p1 = Person::from("Mark,20"); - println!("{p1:?}"); - - // Since `From` is implemented for Person, we are able to use `Into`. - let p2: Person = "Gerald,70".into(); - println!("{p2:?}"); -} - -#[cfg(test)] -mod tests { - use super::*; - - #[test] - fn test_default() { - let dp = Person::default(); - assert_eq!(dp.name, "John"); - assert_eq!(dp.age, 30); - } - - #[test] - fn test_bad_convert() { - let p = Person::from(""); - assert_eq!(p.name, "John"); - assert_eq!(p.age, 30); - } - - #[test] - fn test_good_convert() { - let p = Person::from("Mark,20"); - assert_eq!(p.name, "Mark"); - assert_eq!(p.age, 20); - } - - #[test] - fn test_bad_age() { - let p = Person::from("Mark,twenty"); - assert_eq!(p.name, "John"); - assert_eq!(p.age, 30); - } - - #[test] - fn test_missing_comma_and_age() { - let p: Person = Person::from("Mark"); - assert_eq!(p.name, "John"); - assert_eq!(p.age, 30); - } - - #[test] - fn test_missing_age() { - let p: Person = Person::from("Mark,"); - assert_eq!(p.name, "John"); - assert_eq!(p.age, 30); - } - - #[test] - fn test_missing_name() { - let p: Person = Person::from(",1"); - assert_eq!(p.name, "John"); - assert_eq!(p.age, 30); - } - - #[test] - fn test_missing_name_and_age() { - let p: Person = Person::from(","); - assert_eq!(p.name, "John"); - assert_eq!(p.age, 30); - } - - #[test] - fn test_missing_name_and_invalid_age() { - let p: Person = Person::from(",one"); - assert_eq!(p.name, "John"); - assert_eq!(p.age, 30); - } - - #[test] - fn test_trailing_comma() { - let p: Person = Person::from("Mike,32,"); - assert_eq!(p.name, "John"); - assert_eq!(p.age, 30); - } - - #[test] - fn test_trailing_comma_and_some_string() { - let p: Person = Person::from("Mike,32,dog"); - assert_eq!(p.name, "John"); - assert_eq!(p.age, 30); - } -} diff --git a/rustlings/exercises/23_conversions/from_str.rs b/rustlings/exercises/23_conversions/from_str.rs deleted file mode 100644 index ec6d3fd..0000000 --- a/rustlings/exercises/23_conversions/from_str.rs +++ /dev/null @@ -1,113 +0,0 @@ -// This is similar to the previous `from_into` exercise. But this time, we'll -// implement `FromStr` and return errors instead of falling back to a default -// value. Additionally, upon implementing `FromStr`, you can use the `parse` -// method on strings to generate an object of the implementor type. You can read -// more about it in the documentation: -// https://doc.rust-lang.org/std/str/trait.FromStr.html - -use std::num::ParseIntError; -use std::str::FromStr; - -#[derive(Debug, PartialEq)] -struct Person { - name: String, - age: u8, -} - -// We will use this error type for the `FromStr` implementation. -#[derive(Debug, PartialEq)] -enum ParsePersonError { - // Incorrect number of fields - BadLen, - // Empty name field - NoName, - // Wrapped error from parse::<u8>() - ParseInt(ParseIntError), -} - -// TODO: Complete this `FromStr` implementation to be able to parse a `Person` -// out of a string in the form of "Mark,20". -// Note that you'll need to parse the age component into a `u8` with something -// like `"4".parse::<u8>()`. -// -// Steps: -// 1. Split the given string on the commas present in it. -// 2. If the split operation returns less or more than 2 elements, return the -// error `ParsePersonError::BadLen`. -// 3. Use the first element from the split operation as the name. -// 4. If the name is empty, return the error `ParsePersonError::NoName`. -// 5. Parse the second element from the split operation into a `u8` as the age. -// 6. If parsing the age fails, return the error `ParsePersonError::ParseInt`. -impl FromStr for Person { - type Err = ParsePersonError; - - fn from_str(s: &str) -> Result<Self, Self::Err> {} -} - -fn main() { - let p = "Mark,20".parse::<Person>(); - println!("{p:?}"); -} - -#[cfg(test)] -mod tests { - use super::*; - use ParsePersonError::*; - - #[test] - fn empty_input() { - assert_eq!("".parse::<Person>(), Err(BadLen)); - } - - #[test] - fn good_input() { - let p = "John,32".parse::<Person>(); - assert!(p.is_ok()); - let p = p.unwrap(); - assert_eq!(p.name, "John"); - assert_eq!(p.age, 32); - } - - #[test] - fn missing_age() { - assert!(matches!("John,".parse::<Person>(), Err(ParseInt(_)))); - } - - #[test] - fn invalid_age() { - assert!(matches!("John,twenty".parse::<Person>(), Err(ParseInt(_)))); - } - - #[test] - fn missing_comma_and_age() { - assert_eq!("John".parse::<Person>(), Err(BadLen)); - } - - #[test] - fn missing_name() { - assert_eq!(",1".parse::<Person>(), Err(NoName)); - } - - #[test] - fn missing_name_and_age() { - assert!(matches!(",".parse::<Person>(), Err(NoName | ParseInt(_)))); - } - - #[test] - fn missing_name_and_invalid_age() { - assert!(matches!( - ",one".parse::<Person>(), - Err(NoName | ParseInt(_)), - )); - } - - #[test] - fn trailing_comma() { - assert_eq!("John,32,".parse::<Person>(), Err(BadLen)); - } - - #[test] - fn trailing_comma_and_some_string() { - assert_eq!("John,32,man".parse::<Person>(), Err(BadLen)); - } -} diff --git a/rustlings/exercises/23_conversions/try_from_into.rs b/rustlings/exercises/23_conversions/try_from_into.rs deleted file mode 100644 index f3ae80a..0000000 --- a/rustlings/exercises/23_conversions/try_from_into.rs +++ /dev/null @@ -1,177 +0,0 @@ -// `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)] -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, -} - -// 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<Self, Self::Error> {} -} - -// TODO: Array implementation. -impl TryFrom<[i16; 3]> for Color { - type Error = IntoColorError; - - fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> {} -} - -// 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<Self, Self::Error> {} -} - -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<Color, _> = [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<Color, _> = (&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<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(IntConversion)); - } - - #[test] - fn test_array_out_of_range_negative() { - let c: Result<Color, _> = [-10, -256, -1].try_into(); - assert_eq!(c, Err(IntConversion)); - } - - #[test] - fn test_array_sum() { - let c: Result<Color, _> = [-1, 255, 255].try_into(); - assert_eq!(c, Err(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(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, _> = 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)); - } -} diff --git a/rustlings/exercises/23_conversions/using_as.rs b/rustlings/exercises/23_conversions/using_as.rs deleted file mode 100644 index c131d1f..0000000 --- a/rustlings/exercises/23_conversions/using_as.rs +++ /dev/null @@ -1,24 +0,0 @@ -// Type casting in Rust is done via the usage of the `as` operator. -// Note that the `as` operator is not only used when type casting. It also helps -// with renaming imports. - -fn average(values: &[f64]) -> f64 { - let total = values.iter().sum::<f64>(); - // TODO: Make a conversion before dividing. - total / values.len() -} - -fn main() { - let values = [3.5, 0.3, 13.0, 11.7]; - println!("{}", average(&values)); -} - -#[cfg(test)] -mod tests { - use super::*; - - #[test] - fn returns_proper_type_and_value() { - assert_eq!(average(&[3.5, 0.3, 13.0, 11.7]), 7.125); - } -} |