Fixes per MR review

Author: frank-at-adacore

courses/rust_essentials/120_std_traits/03-operators.rst

@@ -20,28 +20,27 @@ Operator Overloading
 Example
 ---------
 
+Define an implementation for :rust:`Inches` that returns a number in :rust:`Feet`
+
 .. code:: rust
 
-  #[derive(Debug, Copy, Clone)]
-  struct Point {
-      x: i32,
-      y: i32,
-  }
+  struct Feet(f64);
+  struct Inches(f64);
 
-  impl std::ops::Add for Point {
-      type Output = Self;
+  impl std::ops::Add for Inches {
+      type Output = Feet;
 
-      fn add(self, other: Self) -> Self {
-          Self { x: self.x + other.x, y: self.y + other.y }
+      fn add(self, rhs: Self) -> Self::Output {
+          Feet((self.0 + rhs.0) / 12.0)
       }
   }
 
   fn main() {
-      let p1 = Point { x: 10, y: 20 };
-      let p2 = Point { x: 100, y: 200 };
-      println!("{p1:?} + {p2:?} = {:?}", p1 + p2);
+      let measure1 = Inches(10.0);
+      let measure2 = Inches(32.0);
+    
+      println!("{} inches + {} inches", measure1.0, measure2.0);
+    
+      let feet = measure1 + measure2;
+      println!("= {} feet", feet.0);
   }
-
-.. note::
-
-  :rust:`Output` is an associated type — implementer decides the result type

courses/rust_essentials/120_std_traits/04-type_conversions.rst

@@ -43,3 +43,33 @@ Example
     let one: i16 = true.into();
     let bigger: i32 = 123_i16.into();
 
+------------------
+"From" vs "Into"
+------------------
+
+* Implementation
+
+  * If you implement :rust:`From`, you automatically get :rust:`Into`
+
+* Specificity
+
+  * :rust:`From` specifies both source and destination
+
+    .. code:: rust
+
+      let result = Feet::from(measure);
+
+    * :rust:`result` is in :rust:`Feet`
+      
+  * :rust:`Into` is called on an object
+
+    * Compiler might not know the source
+    * Need to supply hints
+
+    .. code:: rust
+
+      // What do we want 'target' to be?
+      let target = source.into(); 
+
+      // You have to help it:
+      let target: Feet = source.into();

courses/rust_essentials/120_std_traits/05-casting.rst

@@ -6,7 +6,7 @@ Casting
 Conversion Between Numbers and Pointers
 -----------------------------------------
 
-* Casting traits help interpet/transform values
+* Casting traits help interpret/transform values
 
   * Convert between numeric and pointer types
 

courses/rust_essentials/120_std_traits/06-io_traits.rst

@@ -14,7 +14,9 @@ Reading and Writing via Trait
 * Why It Matters
 
   * Central to Rust’s I/O ecosystem (files, network, buffers)
-  * Trait-based so many types can be read from / written to generically
+  * Trait-based
+
+    * Many types can be read from / written to generically
 
 --------------------
 Practical Patterns

courses/rust_essentials/120_std_traits/07-default_values.rst

@@ -35,11 +35,14 @@ Example
 
   .. code:: rust
 
-    let c = Config::default();
+    let example = Config::default();
+    println!("Defaults: {example:?}");
 
   * :rust:`default` uses sensible default values for :rust:`port`,
     :rust:`host`, and :rust:`debug`
 
+    :command:`Defaults: Config { port: 0, host: "", debug: false }`
+
 * Using *struct update syntax*
 
   .. code:: rust