summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
Diffstat
-rw-r--r--exercises/13_error_handling/errors6.rs71
-rw-r--r--rustlings-macros/info.toml10
-rw-r--r--solutions/13_error_handling/errors6.rs93
3 files changed, 130 insertions, 44 deletions
diff --git a/exercises/13_error_handling/errors6.rs b/exercises/13_error_handling/errors6.rs
index 8b08e08..0652abd 100644
--- a/exercises/13_error_handling/errors6.rs
+++ b/exercises/13_error_handling/errors6.rs
@@ -1,12 +1,18 @@
-// Using catch-all error types like `Box<dyn error::Error>` isn't recommended
-// for library code, where callers might want to make decisions based on the
-// error content, instead of printing it out or propagating it further. Here, we
-// define a custom error type to make it possible for callers to decide what to
-// do next when our function returns an error.
+// Using catch-all error types like `Box<dyn Error>` isn't recommended for
+// library code where callers might want to make decisions based on the error
+// content instead of printing it out or propagating it further. Here, we define
+// a custom error type to make it possible for callers to decide what to do next
+// when our function returns an error.
use std::num::ParseIntError;
-// This is a custom error type that we will be using in `parse_pos_nonzero()`.
+#[derive(PartialEq, Debug)]
+enum CreationError {
+ Negative,
+ Zero,
+}
+
+// A custom error type that we will be using in `PositiveNonzeroInteger::parse`.
#[derive(PartialEq, Debug)]
enum ParsePosNonzeroError {
Creation(CreationError),
@@ -14,39 +20,32 @@ enum ParsePosNonzeroError {
}
impl ParsePosNonzeroError {
- fn from_creation(err: CreationError) -> ParsePosNonzeroError {
- ParsePosNonzeroError::Creation(err)
+ fn from_creation(err: CreationError) -> Self {
+ Self::Creation(err)
}
- // TODO: add another error conversion function here.
- // fn from_parseint...
-}
-fn parse_pos_nonzero(s: &str) -> Result<PositiveNonzeroInteger, ParsePosNonzeroError> {
- // TODO: change this to return an appropriate error instead of panicking
- // when `parse()` returns an error.
- let x: i64 = s.parse().unwrap();
- PositiveNonzeroInteger::new(x).map_err(ParsePosNonzeroError::from_creation)
+ // TODO: Add another error conversion function here.
+ // fn from_parseint(???) -> Self { ??? }
}
-// Don't change anything below this line.
-
#[derive(PartialEq, Debug)]
struct PositiveNonzeroInteger(u64);
-#[derive(PartialEq, Debug)]
-enum CreationError {
- Negative,
- Zero,
-}
-
impl PositiveNonzeroInteger {
- fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
+ fn new(value: i64) -> Result<Self, CreationError> {
match value {
x if x < 0 => Err(CreationError::Negative),
x if x == 0 => Err(CreationError::Zero),
- x => Ok(PositiveNonzeroInteger(x as u64)),
+ x => Ok(Self(x as u64)),
}
}
+
+ fn parse(s: &str) -> Result<Self, ParsePosNonzeroError> {
+ // TODO: change this to return an appropriate error instead of panicking
+ // when `parse()` returns an error.
+ let x: i64 = s.parse().unwrap();
+ Self::new(x).map_err(ParsePosNonzeroError::from_creation)
+ }
}
fn main() {
@@ -56,36 +55,36 @@ fn main() {
#[cfg(test)]
mod test {
use super::*;
+ use std::num::IntErrorKind;
#[test]
fn test_parse_error() {
- // We can't construct a ParseIntError, so we have to pattern match.
assert!(matches!(
- parse_pos_nonzero("not a number"),
- Err(ParsePosNonzeroError::ParseInt(_))
+ PositiveNonzeroInteger::parse("not a number"),
+ Err(ParsePosNonzeroError::ParseInt(_)),
));
}
#[test]
fn test_negative() {
assert_eq!(
- parse_pos_nonzero("-555"),
- Err(ParsePosNonzeroError::Creation(CreationError::Negative))
+ PositiveNonzeroInteger::parse("-555"),
+ Err(ParsePosNonzeroError::Creation(CreationError::Negative)),
);
}
#[test]
fn test_zero() {
assert_eq!(
- parse_pos_nonzero("0"),
- Err(ParsePosNonzeroError::Creation(CreationError::Zero))
+ PositiveNonzeroInteger::parse("0"),
+ Err(ParsePosNonzeroError::Creation(CreationError::Zero)),
);
}
#[test]
fn test_positive() {
- let x = PositiveNonzeroInteger::new(42);
- assert!(x.is_ok());
- assert_eq!(parse_pos_nonzero("42"), Ok(x.unwrap()));
+ let x = PositiveNonzeroInteger::new(42).unwrap();
+ assert_eq!(x.0, 42);
+ assert_eq!(PositiveNonzeroInteger::parse("42"), Ok(x));
}
}
diff --git a/rustlings-macros/info.toml b/rustlings-macros/info.toml
index 700c179..dc288c0 100644
--- a/rustlings-macros/info.toml
+++ b/rustlings-macros/info.toml
@@ -714,17 +714,13 @@ https://doc.rust-lang.org/stable/rust-by-example/error/multiple_error_types/reen
name = "errors6"
dir = "13_error_handling"
hint = """
-This exercise uses a completed version of `PositiveNonzeroInteger` from
-errors4.
+This exercise uses a completed version of `PositiveNonzeroInteger` from the
+previous exercises.
Below the line that `TODO` asks you to change, there is an example of using
the `map_err()` method on a `Result` to transform one type of error into
another. Try using something similar on the `Result` from `parse()`. You
-might use the `?` operator to return early from the function, or you might
-use a `match` expression, or maybe there's another way!
-
-You can create another function inside `impl ParsePosNonzeroError` to use
-with `map_err()`.
+can then use the `?` operator to return early.
Read more about `map_err()` in the `std::result` documentation:
https://doc.rust-lang.org/std/result/enum.Result.html#method.map_err"""
diff --git a/solutions/13_error_handling/errors6.rs b/solutions/13_error_handling/errors6.rs
index 4e18198..70680cf 100644
--- a/solutions/13_error_handling/errors6.rs
+++ b/solutions/13_error_handling/errors6.rs
@@ -1 +1,92 @@
-// Solutions will be available before the stable release. Thank you for testing the beta version 🥰
+// Using catch-all error types like `Box<dyn Error>` isn't recommended for
+// library code where callers might want to make decisions based on the error
+// content instead of printing it out or propagating it further. Here, we define
+// a custom error type to make it possible for callers to decide what to do next
+// when our function returns an error.
+
+use std::num::ParseIntError;
+
+#[derive(PartialEq, Debug)]
+enum CreationError {
+ Negative,
+ Zero,
+}
+
+// A custom error type that we will be using in `PositiveNonzeroInteger::parse`.
+#[derive(PartialEq, Debug)]
+enum ParsePosNonzeroError {
+ Creation(CreationError),
+ ParseInt(ParseIntError),
+}
+
+impl ParsePosNonzeroError {
+ fn from_creation(err: CreationError) -> Self {
+ Self::Creation(err)
+ }
+
+ fn from_parseint(err: ParseIntError) -> Self {
+ Self::ParseInt(err)
+ }
+}
+
+#[derive(PartialEq, Debug)]
+struct PositiveNonzeroInteger(u64);
+
+impl PositiveNonzeroInteger {
+ fn new(value: i64) -> Result<Self, CreationError> {
+ match value {
+ x if x < 0 => Err(CreationError::Negative),
+ x if x == 0 => Err(CreationError::Zero),
+ x => Ok(Self(x as u64)),
+ }
+ }
+
+ fn parse(s: &str) -> Result<Self, ParsePosNonzeroError> {
+ // Return an appropriate error instead of panicking when `parse()`
+ // returns an error.
+ let x: i64 = s.parse().map_err(ParsePosNonzeroError::from_parseint)?;
+ // ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ Self::new(x).map_err(ParsePosNonzeroError::from_creation)
+ }
+}
+
+fn main() {
+ // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod test {
+ use super::*;
+ use std::num::IntErrorKind;
+
+ #[test]
+ fn test_parse_error() {
+ assert!(matches!(
+ PositiveNonzeroInteger::parse("not a number"),
+ Err(ParsePosNonzeroError::ParseInt(_)),
+ ));
+ }
+
+ #[test]
+ fn test_negative() {
+ assert_eq!(
+ PositiveNonzeroInteger::parse("-555"),
+ Err(ParsePosNonzeroError::Creation(CreationError::Negative)),
+ );
+ }
+
+ #[test]
+ fn test_zero() {
+ assert_eq!(
+ PositiveNonzeroInteger::parse("0"),
+ Err(ParsePosNonzeroError::Creation(CreationError::Zero)),
+ );
+ }
+
+ #[test]
+ fn test_positive() {
+ let x = PositiveNonzeroInteger::new(42).unwrap();
+ assert_eq!(x.0, 42);
+ assert_eq!(PositiveNonzeroInteger::parse("42"), Ok(x));
+ }
+}
generated by cgit v1.2.3 (git 2.46.0) at 2026-04-07 05:52:17 +0000