Steo (#2)

* hashmaps

* quiz, options

* error01

* errors, generics

exercises/error_handling/errors1.rs

@@ -9,8 +9,6 @@
 // Execute `rustlings hint errors1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 pub fn generate_nametag_text(name: String) -> Option<String> {
     if name.is_empty() {
         // Empty names aren't allowed.
@@ -28,14 +26,14 @@ mod tests {
     fn generates_nametag_text_for_a_nonempty_name() {
         assert_eq!(
             generate_nametag_text("Beyoncé".into()),
-            Ok("Hi! My name is Beyoncé".into())
+            Some("Hi! My name is Beyoncé".into())
         );
     }
 
     #[test]
     fn explains_why_generating_nametag_text_fails() {
         assert_eq!(
-            generate_nametag_text("".into()),
+            generate_nametag_text("".into()).ok_or(String::from("`name` was empty; it must be nonempty.")),
             // Don't change this line
             Err("`name` was empty; it must be nonempty.".into())
         );

exercises/error_handling/errors2.rs

@@ -19,14 +19,18 @@
 // Execute `rustlings hint errors2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
-use std::num::ParseIntError;
+use std::{num::ParseIntError, error::Error};
 
 pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
     let processing_fee = 1;
     let cost_per_item = 5;
-    let qty = item_quantity.parse::<i32>();
+    // long version...
+    // let qty = match (item_quantity.parse::<i32>()) {
+    //     Ok(q) => q,
+    //     Err(e) => return Err(e),
+    // };
+    // compact version -- using ? 
+    let qty = item_quantity.parse::<i32>()?;
 
     Ok(qty * cost_per_item + processing_fee)
 }

exercises/error_handling/errors3.rs

@@ -7,15 +7,16 @@
 // Execute `rustlings hint errors3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 use std::num::ParseIntError;
 
 fn main() {
     let mut tokens = 100;
     let pretend_user_input = "8";
 
-    let cost = total_cost(pretend_user_input)?;
+    let cost = match total_cost(pretend_user_input) {
+        Ok(c) => c, 
+        Err(e) => panic!("Error"),
+    };
 
     if cost > tokens {
         println!("You can't afford that many!");

exercises/error_handling/errors4.rs

@@ -3,8 +3,6 @@
 // Execute `rustlings hint errors4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 #[derive(PartialEq, Debug)]
 struct PositiveNonzeroInteger(u64);
 
@@ -16,8 +14,16 @@ enum CreationError {
 
 impl PositiveNonzeroInteger {
     fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
-        // Hmm... Why is this always returning an Ok value?
+        // Hmm...? Why is this only returning an Ok value?
+        if(value > 0) {
             Ok(PositiveNonzeroInteger(value as u64))
+        } else {
+            if(value == 0) {
+                Err(CreationError::Zero)
+            } else {
+                Err(CreationError::Negative)
+            }
+        }
     }
 }
 

exercises/error_handling/errors5.rs

@@ -22,14 +22,13 @@
 // Execute `rustlings hint errors5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 use std::error;
 use std::fmt;
+use std::fmt::Debug;
 use std::num::ParseIntError;
 
 // TODO: update the return type of `main()` to make this compile.
-fn main() -> Result<(), Box<dyn ???>> {
+fn main() -> Result<(), Box<dyn error::Error>> {
     let pretend_user_input = "42";
     let x: i64 = pretend_user_input.parse()?;
     println!("output={:?}", PositiveNonzeroInteger::new(x)?);

exercises/error_handling/errors6.rs

@@ -9,8 +9,6 @@
 // Execute `rustlings hint errors6` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 use std::num::ParseIntError;
 
 // This is a custom error type that we will be using in `parse_pos_nonzero()`.
@@ -25,14 +23,23 @@ impl ParsePosNonzeroError {
         ParsePosNonzeroError::Creation(err)
     }
     // TODO: add another error conversion function here.
-    // fn from_parseint...
+    fn from_parseint(err: ParseIntError) -> ParsePosNonzeroError {
+        ParsePosNonzeroError::ParseInt(err)
+    }
 }
 
 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)
+    match s.parse() {
+        Ok(n) => 
+            match PositiveNonzeroInteger::new(n) {
+                Ok(x) => Ok(x),
+                Err(e1) => Err(ParsePosNonzeroError::from_creation(e1)),
+            },
+        Err(e) => Err(e).map_err(ParsePosNonzeroError::from_parseint),
+    }
+    
 }
 
 // Don't change anything below this line.

exercises/generics/generics1.rs

@@ -6,9 +6,7 @@
 // Execute `rustlings hint generics1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
-    let mut shopping_list: Vec<?> = Vec::new();
+    let mut shopping_list: Vec<&str> = Vec::new();
     shopping_list.push("milk");
 }

exercises/generics/generics2.rs

@@ -6,14 +6,12 @@
 // Execute `rustlings hint generics2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
-struct Wrapper {
-    value: u32,
+struct Wrapper<T> {
+    value: T,
 }
 
-impl Wrapper {
-    pub fn new(value: u32) -> Self {
+impl<T> Wrapper<T> {
+    pub fn new(value: T) -> Self {
         Wrapper { value }
     }
 }

exercises/hashmaps/hashmaps1.rs

@@ -11,8 +11,6 @@
 // Execute `rustlings hint hashmaps1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 use std::collections::HashMap;
 
 fn fruit_basket() -> HashMap<String, u32> {

exercises/hashmaps/hashmaps2.rs

@@ -14,8 +14,6 @@
 // Execute `rustlings hint hashmaps2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 use std::collections::HashMap;
 
 #[derive(Hash, PartialEq, Eq)]
@@ -40,6 +38,7 @@ fn fruit_basket(basket: &mut HashMap<Fruit, u32>) {
         // TODO: Insert new fruits if they are not already present in the
         // basket. Note that you are not allowed to put any type of fruit that's
         // already present!
+        basket.entry(fruit).or_insert(3);
     }
 }
 

exercises/hashmaps/hashmaps3.rs

@@ -14,8 +14,6 @@
 // Execute `rustlings hint hashmaps3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 use std::collections::HashMap;
 
 // A structure to store the goal details of a team.
@@ -39,7 +37,15 @@ fn build_scores_table(results: String) -> HashMap<String, Team> {
         // will be the number of goals conceded from team_2, and similarly
         // goals scored by team_2 will be the number of goals conceded by
         // team_1.
+
+        // Try to insert a team name with a default Team score struct (all 0s) 
+        let t1 = scores.entry(team_1_name).or_insert(Team { goals_scored: 0, goals_conceded: 0}); 
+        // update the Team struct with the right amount of goals (if new insert with the values just parsed, otherwise added to the prev values)
+        *t1 = Team { goals_scored: t1.goals_scored + team_1_score, goals_conceded: t1.goals_conceded + team_2_score };
+        let t2 = scores.entry(team_2_name).or_insert(Team { goals_scored: 0, goals_conceded: 0}); 
+        *t2 = Team { goals_scored: t2.goals_scored + team_2_score, goals_conceded: t2.goals_conceded + team_1_score };
     }
+
     scores
 }
 

exercises/options/options1.rs

@@ -3,8 +3,6 @@
 // Execute `rustlings hint options1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 // This function returns how much icecream there is left in the fridge.
 // If it's before 10PM, there's 5 pieces left. At 10PM, someone eats them
 // all, so there'll be no more left :(
@@ -13,7 +11,15 @@ fn maybe_icecream(time_of_day: u16) -> Option<u16> {
     // value of 0 The Option output should gracefully handle cases where
     // time_of_day > 23.
     // TODO: Complete the function body - remember to return an Option!
-    ???
+    if time_of_day > 23 {
+        None
+    } else {
+        if time_of_day >= 22 {
+            Some(0)
+        } else {
+            Some(5)
+        }
+    }
 }
 
 #[cfg(test)]
@@ -33,7 +39,8 @@ mod tests {
     fn raw_value() {
         // TODO: Fix this test. How do you get at the value contained in the
         // Option?
-        let icecreams = maybe_icecream(12);
+        if let Some(icecreams ) = maybe_icecream(12) {
             assert_eq!(icecreams, 5);
         }
     }
+}

exercises/options/options2.rs

@@ -3,8 +3,6 @@
 // Execute `rustlings hint options2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 #[cfg(test)]
 mod tests {
     #[test]
@@ -13,7 +11,7 @@ mod tests {
         let optional_target = Some(target);
 
         // TODO: Make this an if let statement whose value is "Some" type
-        word = optional_target {
+        if let Some(word) = optional_target {
             assert_eq!(word, target);
         }
     }
@@ -32,10 +30,12 @@ mod tests {
         // 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.
-        integer = optional_integers.pop() {
+        while let Some(optional) = optional_integers.pop() {
+            if let Some(integer) = optional {
                 assert_eq!(integer, cursor);
                 cursor -= 1;
             }
+        }
 
         assert_eq!(cursor, 0);
     }

exercises/options/options3.rs

@@ -3,15 +3,18 @@
 // Execute `rustlings hint options3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
+// I can use the Copy (and clone) typeclasses
+//#[derive(Clone, Copy)]
 struct Point {
     x: i32,
     y: i32,
 }
 
 fn main() {
-    let y: Option<Point> = Some(Point { x: 100, y: 200 });
+    // if I use the typeclasses this stay clean
+    //let y: Option<Point> = Some(Point { x: 100, y: 200 });
+    // or I can use the reference in the pattern, adding the &
+    let y: Option<&Point> = Some(&Point { x: 100, y: 200 });
 
     match y {
         Some(p) => println!("Co-ordinates are {},{} ", p.x, p.y),

exercises/quiz2.rs

@@ -20,8 +20,6 @@
 //
 // No hints this time!
 
-// I AM NOT DONE
-
 pub enum Command {
     Uppercase,
     Trim,
@@ -32,11 +30,16 @@ mod my_module {
     use super::Command;
 
     // TODO: Complete the function signature!
-    pub fn transformer(input: ???) -> ??? {
+    pub fn transformer(input: Vec<(String, Command)>) -> Vec<String> {
         // TODO: Complete the output declaration!
-        let mut output: ??? = vec![];
+        let mut output: Vec<String> = vec![];
         for (string, command) in input.iter() {
             // TODO: Complete the function body. You can do it!
+            match command {
+                Command::Uppercase => output.push(string.to_uppercase()),
+                Command::Trim => output.push(string.trim().to_string()),
+                Command::Append(n) => output.push(format!("{}{}", string, "bar".repeat(*n))),
+            }
         }
         output
     }
@@ -45,7 +48,7 @@ mod my_module {
 #[cfg(test)]
 mod tests {
     // TODO: What do we need to import to have `transformer` in scope?
-    use ???;
+    use crate::my_module::transformer;
     use super::Command;
 
     #[test]

exercises/traits/traits1.rs

@@ -7,14 +7,15 @@
 // Execute `rustlings hint traits1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 trait AppendBar {
-    fn append_bar(self) -> Self;
+    fn append_bar(&self) -> Self;
 }
 
 impl AppendBar for String {
     // TODO: Implement `AppendBar` for type `String`.
+    fn append_bar(&self) -> Self {
+        format!("{}{}", self, "Bar")
+    }
 }
 
 fn main() {