Merge 59e8f70e55 into 47976caa69

dev/Cargo.toml

@@ -116,6 +116,8 @@ bin = [
   { name = "generics1_sol", path = "../solutions/14_generics/generics1.rs" },
   { name = "generics2", path = "../exercises/14_generics/generics2.rs" },
   { name = "generics2_sol", path = "../solutions/14_generics/generics2.rs" },
+  { name = "generics3", path = "../exercises/14_generics/generics3.rs" },
+  { name = "generics3_sol", path = "../solutions/14_generics/generics3.rs" },
   { name = "traits1", path = "../exercises/15_traits/traits1.rs" },
   { name = "traits1_sol", path = "../solutions/15_traits/traits1.rs" },
   { name = "traits2", path = "../exercises/15_traits/traits2.rs" },

exercises/13_error_handling/errors4.rs

@@ -1,5 +1,3 @@
-#![allow(clippy::comparison_chain)]
-
 #[derive(PartialEq, Debug)]
 enum CreationError {
     Negative,

exercises/14_generics/generics3.rs

@@ -0,0 +1,54 @@
+// generics3.rs
+// Execute `rustlings hint generics3` or use the `hint` watch subcommand for a hint.
+
+// This function should take an array of `Option` elements and returns array of not None elements
+// TODO fix this function signature
+fn into_dispose_nulls(list: Vec<Option<&str>>) -> Vec<&str> {
+    list.into_iter().flatten().collect()
+}
+
+fn main() {
+    // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn store_str_on_list() {
+        let names_list = vec![Some("maria"), Some("jacob"), None, Some("kacper"), None];
+        let only_values = into_dispose_nulls(names_list);
+        assert_eq!(only_values.len(), 3);
+    }
+
+    #[test]
+    fn store_numbers_on_list() {
+        let numbers_list = vec![Some(1), Some(2), None, Some(3)];
+        let only_values = into_dispose_nulls(numbers_list);
+        assert_eq!(only_values.len(), 3);
+    }
+
+    #[test]
+    fn store_custom_type_on_list() {
+        #[allow(dead_code)]
+        struct Rectangle {
+            width: i32,
+            height: i32,
+        }
+        impl Rectangle {
+            fn new(width: i32, height: i32) -> Self {
+                Self { width, height }
+            }
+        }
+
+        let custom_list = vec![
+            Some(Rectangle::new(1, 2)),
+            None,
+            None,
+            Some(Rectangle::new(3, 4)),
+        ];
+        let only_values = into_dispose_nulls(custom_list);
+        assert_eq!(only_values.len(), 2);
+    }
+}

rustlings-macros/info.toml

@@ -744,6 +744,17 @@ hint = """
 Related section in The Book:
 https://doc.rust-lang.org/book/ch10-01-syntax.html#in-method-definitions"""
 
+[[exercises]]
+name = "generics3"
+dir = "14_generics"
+hint = """
+Vectors in Rust use generics to create dynamically-sized arrays of any type.
+The `into_dispose_nulls` function takes a vector as an argument, but only accepts vectors that store the &str type.
+To allow the function to accept vectors that store any type, you can leverage your knowledge about generics.
+If you're unsure how to proceed, please refer to the Rust Book at:
+https://doc.rust-lang.org/book/ch10-01-syntax.html#in-function-definitions.
+"""
+
 # TRAITS
 
 [[exercises]]

solutions/09_strings/strings4.rs

@@ -18,12 +18,11 @@ fn main() {
     // Here, both answers work.
     // `.into()` converts a type into an expected type.
     // If it is called where `String` is expected, it will convert `&str` to `String`.
-    // But if is called where `&str` is expected, then `&str` is kept `&str` since no
-    // conversion is needed.
     string("nice weather".into());
+    // But if it is called where `&str` is expected, then `&str` is kept `&str` since no conversion is needed.
+    // If you remove the `#[allow(…)]` line, then Clippy will tell you to remove `.into()` below since it is a useless conversion.
+    #[allow(clippy::useless_conversion)]
     string_slice("nice weather".into());
-    //                         ^^^^^^^ the compiler recommends removing the `.into()`
-    //                                 call because it is a useless conversion.
 
     string(format!("Interpolation {}", "Station"));
 

solutions/13_error_handling/errors4.rs

@@ -1,4 +1,4 @@
-#![allow(clippy::comparison_chain)]
+use std::cmp::Ordering;
 
 #[derive(PartialEq, Debug)]
 enum CreationError {
@@ -11,12 +11,10 @@ struct PositiveNonzeroInteger(u64);
 
 impl PositiveNonzeroInteger {
     fn new(value: i64) -> Result<Self, CreationError> {
-        if value == 0 {
-            Err(CreationError::Zero)
-        } else if value < 0 {
-            Err(CreationError::Negative)
-        } else {
-            Ok(Self(value as u64))
+        match value.cmp(&0) {
+            Ordering::Less => Err(CreationError::Negative),
+            Ordering::Equal => Err(CreationError::Zero),
+            Ordering::Greater => Ok(Self(value as u64)),
         }
     }
 }

solutions/14_generics/generics3.rs

@@ -0,0 +1,53 @@
+// generics3.rs
+// Execute `rustlings hint generics3` or use the `hint` watch subcommand for a hint.
+
+// Here we added generic type `T` to function signature
+// Now this function can be used with vector of any
+fn into_dispose_nulls<T>(list: Vec<Option<T>>) -> Vec<T> {
+    list.into_iter().flatten().collect()
+}
+
+fn main() {
+    // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn store_str_on_list() {
+        let names_list = vec![Some("maria"), Some("jacob"), None, Some("kacper"), None];
+        let only_values = into_dispose_nulls(names_list);
+        assert_eq!(only_values.len(), 3);
+    }
+
+    #[test]
+    fn store_numbers_on_list() {
+        let numbers_list = vec![Some(1), Some(2), None, Some(3)];
+        let only_values = into_dispose_nulls(numbers_list);
+        assert_eq!(only_values.len(), 3);
+    }
+
+    #[test]
+    fn store_custom_type_on_list() {
+        struct Rectangle {
+            width: i32,
+            height: i32,
+        }
+        impl Rectangle {
+            fn new(width: i32, height: i32) -> Self {
+                Self { width, height }
+            }
+        }
+
+        let custom_list = vec![
+            Some(Rectangle::new(1, 2)),
+            None,
+            None,
+            Some(Rectangle::new(3, 4)),
+        ];
+        let only_values = into_dispose_nulls(custom_list);
+        assert_eq!(only_values.len(), 2);
+    }
+}

solutions/18_iterators/iterators4.rs

@@ -25,6 +25,7 @@ fn factorial_fold(num: u64) -> u64 {
     //              -> 1 * 2 is calculated, then the result 2 is multiplied by
     //                 the second element 3 so the result 6 is returned.
     // And so on…
+    #[allow(clippy::unnecessary_fold)]
     (2..=num).fold(1, |acc, x| acc * x)
 }
 

src/exercise.rs

@@ -72,7 +72,7 @@ pub trait RunnableExercise {
 
     // Compile, check and run the exercise or its solution (depending on `bin_name´).
     // The output is written to the `output` buffer after clearing it.
-    fn run(
+    fn run<const FORCE_STRICT_CLIPPY: bool>(
         &self,
         bin_name: &str,
         mut output: Option<&mut Vec<u8>>,
@@ -115,7 +115,7 @@ pub trait RunnableExercise {
         let mut clippy_cmd = cmd_runner.cargo("clippy", bin_name, output.as_deref_mut());
 
         // `--profile test` is required to also check code with `[cfg(test)]`.
-        if self.strict_clippy() {
+        if FORCE_STRICT_CLIPPY || self.strict_clippy() {
             clippy_cmd.args(["--profile", "test", "--", "-D", "warnings"]);
         } else {
             clippy_cmd.args(["--profile", "test"]);
@@ -131,7 +131,7 @@ pub trait RunnableExercise {
     /// The output is written to the `output` buffer after clearing it.
     #[inline]
     fn run_exercise(&self, output: Option<&mut Vec<u8>>, cmd_runner: &CmdRunner) -> Result<bool> {
-        self.run(self.name(), output, cmd_runner)
+        self.run::<false>(self.name(), output, cmd_runner)
     }
 
     /// Compile, check and run the exercise's solution.
@@ -142,7 +142,7 @@ pub trait RunnableExercise {
         bin_name.push_str(name);
         bin_name.push_str("_sol");
 
-        self.run(&bin_name, output, cmd_runner)
+        self.run::<true>(&bin_name, output, cmd_runner)
     }
 }