diff options
| -rw-r--r-- | exercises/12_options/options2.rs | 10 | ||||
| -rw-r--r-- | rustlings-macros/info.toml | 4 | ||||
| -rw-r--r-- | solutions/12_options/options2.rs | 38 |
3 files changed, 44 insertions, 8 deletions
diff --git a/exercises/12_options/options2.rs b/exercises/12_options/options2.rs index 01f84c5..07c27c6 100644 --- a/exercises/12_options/options2.rs +++ b/exercises/12_options/options2.rs @@ -9,7 +9,7 @@ mod tests { let target = "rustlings"; let optional_target = Some(target); - // TODO: Make this an if let statement whose value is "Some" type + // TODO: Make this an if-let statement whose value is `Some`. word = optional_target { assert_eq!(word, target); } @@ -20,15 +20,15 @@ mod tests { let range = 10; let mut optional_integers: Vec<Option<i8>> = vec![None]; - for i in 1..(range + 1) { + for i in 1..=range { optional_integers.push(Some(i)); } let mut cursor = range; - // TODO: make this a while let statement - remember that vector.pop also - // adds another layer of Option<T>. You can stack `Option<T>`s into - // while let and if let. + // TODO: Make this a while-let statement. Remember that `Vec::pop()` + // adds another layer of `Option`. You can do nested pattern matching + // in if-let and while-let statements. integer = optional_integers.pop() { assert_eq!(integer, cursor); cursor -= 1; diff --git a/rustlings-macros/info.toml b/rustlings-macros/info.toml index 3694b94..6027b6b 100644 --- a/rustlings-macros/info.toml +++ b/rustlings-macros/info.toml @@ -616,9 +616,9 @@ Check out: - https://doc.rust-lang.org/rust-by-example/flow_control/if_let.html - https://doc.rust-lang.org/rust-by-example/flow_control/while_let.html -Remember that `Option`s can be stacked in `if let` and `while let`. +Remember that `Option`s can be nested in if-let and while-let statements. -For example: `Some(Some(variable)) = variable2` +For example: `if let Some(Some(x)) = y` Also see `Option::flatten` """ diff --git a/solutions/12_options/options2.rs b/solutions/12_options/options2.rs index 4e18198..0f24665 100644 --- a/solutions/12_options/options2.rs +++ b/solutions/12_options/options2.rs @@ -1 +1,37 @@ -// Solutions will be available before the stable release. Thank you for testing the beta version 🥰 +fn main() { + // You can optionally experiment here. +} + +#[cfg(test)] +mod tests { + #[test] + fn simple_option() { + let target = "rustlings"; + let optional_target = Some(target); + + // if-let + if let Some(word) = optional_target { + assert_eq!(word, target); + } + } + + #[test] + fn layered_option() { + let range = 10; + let mut optional_integers: Vec<Option<i8>> = vec![None]; + + for i in 1..=range { + optional_integers.push(Some(i)); + } + + let mut cursor = range; + + // while-let with nested pattern matching + while let Some(Some(integer)) = optional_integers.pop() { + assert_eq!(integer, cursor); + cursor -= 1; + } + + assert_eq!(cursor, 0); + } +} |