learnings from seeing listing 13-1

- i was trying to do too much!
- the book keeps it to two colours
- it does not update inventory after each giveaway
- it does not implement a `User` struct
- "Simplicity is key." - DJ Khaled

closures/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "closures"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

closures/src/main.rs

@@ -0,0 +1,63 @@
+// giveaway tshirts to users
+// if someone has a favorite colour they get that
+// else they get whatever colour we currently have the most of
+
+#[derive(Debug, PartialEq, Clone, Copy)]
+enum ShirtColor {
+    Red,
+    Blue,
+}
+
+#[derive(Debug)]
+struct Inventory {
+    shirts: Vec<ShirtColor>,
+}
+
+// #[derive(Debug)]
+// struct User {
+//     shirt_preference: Option<ShirtColor>,
+// }
+
+impl Inventory {
+    fn giveaway(&self, user_pref: Option<ShirtColor>) -> ShirtColor {
+        user_pref.unwrap_or_else(|| self.current_max())
+    }
+
+    fn current_max(&self) -> ShirtColor {
+        let mut red = 0;
+        let mut blue = 0;
+        for color in &self.shirts {
+            match color {
+                ShirtColor::Red => red += 1,
+                ShirtColor::Blue => blue += 1,
+            }
+        }
+        if red > blue {
+            return ShirtColor::Red;
+        } else {
+            return ShirtColor::Blue;
+        }
+    }
+}
+
+fn main() {
+    let current_inventory = Inventory {
+        shirts: vec![
+            ShirtColor::Red,
+            ShirtColor::Red,
+            ShirtColor::Blue,
+            ShirtColor::Blue,
+            ShirtColor::Blue,
+        ],
+    };
+
+    println!("DEBUG: inventory: {:?}", current_inventory);
+
+    let user_red = Some(ShirtColor::Red);
+    let giveaway1 = current_inventory.giveaway(user_red);
+    println!("DEBUG: giveaway {:?} to {:?}", giveaway1, user_red);
+
+    let user_none = None;
+    let giveaway2 = current_inventory.giveaway(user_none);
+    println!("DEBUG: giveaway {:?} to {:?}", giveaway2, user_none);
+}

generics/largest_number/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "generics"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

generics/largest_number/src/main.rs

@@ -0,0 +1,31 @@
+fn main() {
+    let number_list = vec![34, 50, 25, 100, 65];
+    let largest = largest_number(&number_list);
+    println!("The largest number is {largest}");
+    // for number in &number_list {
+    //     if number > largest {
+    //         largest = number;
+    //     }
+    // }
+
+    let number_list = vec![102, 34, 6000, 89, 54, 2, 43, 8];
+    let largest = largest_number(&number_list);
+    println!("The largest number is {largest}");
+    // let mut largest = &number_list[0];
+    // for number in &number_list {
+    // if number > largest {
+    // largest = number;
+    // }
+    // }
+}
+
+fn largest_number(list: &[i32]) -> &i32 {
+    let mut largest = &list[0];
+
+    for number in list {
+        if number > largest {
+            largest = number;
+        }
+    }
+    largest
+}

generics/media-aggregator/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "media-aggregator"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

generics/media-aggregator/src/lib.rs

@@ -0,0 +1,60 @@
+use ::std::fmt::Display;
+use std::fmt::Debug;
+pub trait Summary {
+    fn summarize_author(&self) -> String;
+
+    fn summarize(&self) -> String {
+        // "(Read more...)".to_string()
+        let x = "a".to_string();
+        x
+    }
+}
+
+#[derive(Debug)]
+pub struct NewsArticle {
+    pub headline: String,
+    pub location: String,
+    pub author: String,
+    pub content: String,
+}
+
+#[derive(Debug)]
+pub struct SocialPost {
+    pub username: String,
+    pub content: String,
+    pub reply: bool,
+    pub repost: bool,
+}
+
+impl Summary for NewsArticle {
+    // fn summarize(&self) -> String {
+    // format!("{}, by {} ({})", self.headline, self.author, self.location)
+    // }
+    fn summarize_author(&self) -> String {
+        "trad media".to_string() // format!("@{}", self.author)
+    }
+}
+
+// impl Summary for SocialPost {
+//     fn summarize(&self) -> String {
+//         format!("{} by {}", self.content, self.summarize_author())
+//     }
+//
+//     fn summarize_author(&self) -> String {
+//         format!("@{}", self.username)
+//     }
+// }
+
+// pub fn notify(item: &impl Summary) {
+// println!("{}", item.summarize());
+// }
+
+pub fn notify<T, U>(item: &T, x: U)
+where
+    T: Summary,
+    U: Copy + Debug + Display + Clone,
+{
+    println!("{}", item.summarize());
+    let y = x;
+    println!("doubled: {:?}", y);
+}

generics/media-aggregator/src/main.rs

@@ -0,0 +1,28 @@
+use media_aggregator::{NewsArticle, SocialPost};
+use media_aggregator::{Summary, notify};
+
+fn main() {
+    let article = NewsArticle {
+        headline: "Chancellor on brink of second bailout for banks".to_string(),
+        location: "London".to_string(),
+        author: "The Times".to_string(),
+        content: "Please subscribe to Premium to read the whole story.".to_string(),
+    };
+
+    let tweet = SocialPost {
+        content: "running bitcoin".to_string(),
+        username: "halfin".to_string(),
+        reply: false,
+        repost: false,
+    };
+
+    println!("\n --- DEBUG: values ---");
+    println!("{:?}", article);
+    // println!("{:?}", tweet);
+
+    println!("\n --- DEBUG: article summary ---");
+    println!("{:?}", article.summarize());
+
+    println!("\n --- DEBUG: article notify---");
+    notify(&article, 5);
+}

lifetimes/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "lifetimes"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

lifetimes/src/main.rs

@@ -0,0 +1,26 @@
+// fn main() {
+//     let string1 = String::from("abcd");
+//     let string2 = String::from("xyz");
+//     let result = longest(string1.as_str(), string2.as_str());
+//     println!("The longer string is: {result}");
+// }
+//
+// fn longest<'somelifetime>(a: &'somelifetime str, b: &'somelifetime str) -> &'somelifetime str {
+//     if a.len() > b.len() { a } else { b }
+// }
+//
+struct ImportantExcerpt<'a> {
+    part: &'a str,
+}
+//
+// fn return_excerpt(story: ImportantExcerpt) -> &'a str {
+//     let first_sentence = novel.split('.')
+// }
+
+fn main() {
+    let novel = String::from("Call me Ishmael. Some years ago...");
+    let first_sentence = novel.split('.').next().unwrap();
+    let i = ImportantExcerpt {
+        part: first_sentence,
+    };
+}

minigrep/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "minigrep"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

minigrep/poems.txt

@@ -0,0 +1,10 @@
+I'm nobody! Who are you?
+Are you nobody, too?
+Then there's a pair of us - don't tell!
+They'd banish us, you know.
+
+How dreary to be somebody!
+How public, like a frog
+To tell your name the livelong day
+To an admiring bog!
+

minigrep/src/lib.rs

@@ -0,0 +1,102 @@
+use std::env;
+use std::error::Error;
+use std::fs;
+
+pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
+    let contents = fs::read_to_string(config.file_path)?;
+
+    let mut results;
+    let casing = (config.ignore_case_arg, config.ignore_case_env);
+
+    // only perform case sensitive search if both
+    // ignore_case_env and ignore_case_arg are false
+    match casing {
+        (false, false) => results = search(&config.query, &contents),
+        (_, _) => results = search_case_insensitive(&config.query, &contents),
+    }
+
+    for line in results {
+        println!("{line}");
+    }
+
+    Ok(())
+}
+
+pub struct Config {
+    pub query: String,
+    pub file_path: String,
+    pub ignore_case_arg: bool,
+    pub ignore_case_env: bool,
+}
+
+impl Config {
+    pub fn build(args: &[String]) -> Result<Config, &'static str> {
+        if args.len() < 4 {
+            return Err("not enough arguments");
+        }
+
+        let query = args[1].clone();
+        let file_path = args[2].clone();
+        let ignore_case_arg = !args[3].clone().is_empty();
+        let ignore_case_env = env::var("IGNORE_CASE").is_ok();
+
+        Ok(Config {
+            query,
+            file_path,
+            ignore_case_arg,
+            ignore_case_env,
+        })
+    }
+}
+
+pub fn search<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
+    let mut results = Vec::new();
+    for line in contents.lines() {
+        if line.contains(query) {
+            results.push(line);
+        }
+    }
+    results
+}
+pub fn search_case_insensitive<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
+    let mut results = Vec::new();
+    let query = query.to_lowercase();
+
+    for line in contents.lines() {
+        if line.to_lowercase().contains(&query) {
+            results.push(line);
+        }
+    }
+    results
+}
+
+#[cfg(test)]
+mod tests {
+
+    use super::*;
+
+    #[test]
+    fn case_sensitive() {
+        let query = "duct";
+        let contents = "Rust:
+safe, fast, productive.
+Pick three.
+Duct tape.";
+
+        assert_eq!(vec!["safe, fast, productive."], search(query, contents));
+    }
+
+    #[test]
+    fn case_insensitive() {
+        let query = "rUsT";
+        let contents = "Rust:
+safe, fast, productive.
+Pick three.
+Trust me.";
+
+        assert_eq!(
+            vec!["Rust:", "Trust me."],
+            search_case_insensitive(query, contents)
+        );
+    }
+}

minigrep/src/main.rs

@@ -0,0 +1,34 @@
+use minigrep::Config;
+use std::env;
+use std::process;
+
+fn main() {
+    let args: Vec<String> = env::args().collect();
+
+    let config = Config::build(&args).unwrap_or_else(|error| {
+        println!("Problem parsing arguments: {error}");
+        process::exit(1);
+    });
+
+    if let Err(e) = minigrep::run(config) {
+        println!("Application error: {e}");
+        process::exit(1);
+    }
+}
+
+// end of main
+// another way to handle the Config building
+// let config = Config::build(&args);
+// match config {
+//     Err(error) => {
+//         println!("error: {error}");
+//     }
+//     Ok(config) => {
+//         println!(
+//             "searching for \"{}\" in file \"{}\"",
+//             config.query, config.file_path,
+//         );
+//
+//         println!("with text:\n{contents}");
+//     }
+// }