Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

85 files changed, 1442 insertions, 0 deletions

diff --git a/src/doc/book/listings/ch13-functional-features/listing-12-23-reproduced/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-12-23-reproduced/Cargo.lock
new file mode 100644
index 000000000..88bf82d16
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-12-23-reproduced/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "minigrep"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-12-23-reproduced/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-12-23-reproduced/Cargo.toml
new file mode 100644
index 000000000..64c2a3f52
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-12-23-reproduced/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "minigrep"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-12-23-reproduced/poem.txt b/src/doc/book/listings/ch13-functional-features/listing-12-23-reproduced/poem.txt
new file mode 100644
index 000000000..870752731
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-12-23-reproduced/poem.txt
@@ -0,0 +1,9 @@
+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!
diff --git a/src/doc/book/listings/ch13-functional-features/listing-12-23-reproduced/src/lib.rs b/src/doc/book/listings/ch13-functional-features/listing-12-23-reproduced/src/lib.rs
new file mode 100644
index 000000000..e54343d24
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-12-23-reproduced/src/lib.rs
@@ -0,0 +1,106 @@
+use std::env;
+use std::error::Error;
+use std::fs;
+
+pub struct Config {
+    pub query: String,
+    pub file_path: String,
+    pub ignore_case: bool,
+}
+
+// ANCHOR: ch13
+impl Config {
+    pub fn build(args: &[String]) -> Result<Config, &'static str> {
+        if args.len() < 3 {
+            return Err("not enough arguments");
+        }
+
+        let query = args[1].clone();
+        let file_path = args[2].clone();
+
+        let ignore_case = env::var("IGNORE_CASE").is_ok();
+
+        Ok(Config {
+            query,
+            file_path,
+            ignore_case,
+        })
+    }
+}
+// ANCHOR_END: ch13
+
+pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
+    let contents = fs::read_to_string(config.file_path)?;
+
+    let results = if config.ignore_case {
+        search_case_insensitive(&config.query, &contents)
+    } else {
+        search(&config.query, &contents)
+    };
+
+    for line in results {
+        println!("{line}");
+    }
+
+    Ok(())
+}
+
+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 query = query.to_lowercase();
+    let mut results = Vec::new();
+
+    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)
+        );
+    }
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-12-23-reproduced/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-12-23-reproduced/src/main.rs
new file mode 100644
index 000000000..a4f8a7411
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-12-23-reproduced/src/main.rs
@@ -0,0 +1,18 @@
+use std::env;
+use std::process;
+
+use minigrep::Config;
+
+fn main() {
+    let args: Vec<String> = env::args().collect();
+
+    let config = Config::build(&args).unwrap_or_else(|err| {
+        println!("Problem parsing arguments: {err}");
+        process::exit(1);
+    });
+
+    if let Err(e) = minigrep::run(config) {
+        println!("Application error: {e}");
+        process::exit(1);
+    }
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-12-24-reproduced/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-12-24-reproduced/Cargo.lock
new file mode 100644
index 000000000..88bf82d16
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-12-24-reproduced/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "minigrep"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-12-24-reproduced/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-12-24-reproduced/Cargo.toml
new file mode 100644
index 000000000..64c2a3f52
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-12-24-reproduced/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "minigrep"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-12-24-reproduced/poem.txt b/src/doc/book/listings/ch13-functional-features/listing-12-24-reproduced/poem.txt
new file mode 100644
index 000000000..870752731
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-12-24-reproduced/poem.txt
@@ -0,0 +1,9 @@
+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!
diff --git a/src/doc/book/listings/ch13-functional-features/listing-12-24-reproduced/src/lib.rs b/src/doc/book/listings/ch13-functional-features/listing-12-24-reproduced/src/lib.rs
new file mode 100644
index 000000000..292b09789
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-12-24-reproduced/src/lib.rs
@@ -0,0 +1,104 @@
+use std::env;
+use std::error::Error;
+use std::fs;
+
+pub struct Config {
+    pub query: String,
+    pub file_path: String,
+    pub ignore_case: bool,
+}
+
+impl Config {
+    pub fn build(args: &[String]) -> Result<Config, &'static str> {
+        if args.len() < 3 {
+            return Err("not enough arguments");
+        }
+
+        let query = args[1].clone();
+        let file_path = args[2].clone();
+
+        let ignore_case = env::var("IGNORE_CASE").is_ok();
+
+        Ok(Config {
+            query,
+            file_path,
+            ignore_case,
+        })
+    }
+}
+
+pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
+    let contents = fs::read_to_string(config.file_path)?;
+
+    let results = if config.ignore_case {
+        search_case_insensitive(&config.query, &contents)
+    } else {
+        search(&config.query, &contents)
+    };
+
+    for line in results {
+        println!("{line}");
+    }
+
+    Ok(())
+}
+
+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 query = query.to_lowercase();
+    let mut results = Vec::new();
+
+    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)
+        );
+    }
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-12-24-reproduced/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-12-24-reproduced/src/main.rs
new file mode 100644
index 000000000..f9d179c8c
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-12-24-reproduced/src/main.rs
@@ -0,0 +1,24 @@
+use std::env;
+use std::process;
+
+use minigrep::Config;
+
+// ANCHOR: ch13
+fn main() {
+    let args: Vec<String> = env::args().collect();
+
+    let config = Config::build(&args).unwrap_or_else(|err| {
+        eprintln!("Problem parsing arguments: {err}");
+        process::exit(1);
+    });
+
+    // --snip--
+    // ANCHOR_END: ch13
+
+    if let Err(e) = minigrep::run(config) {
+        eprintln!("Application error: {e}");
+        process::exit(1);
+    }
+    // ANCHOR: ch13
+}
+// ANCHOR_END: ch13
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-01/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-13-01/Cargo.lock
new file mode 100644
index 000000000..6f974d1ba
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-01/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "shirt-company"
+version = "0.1.0"
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-01/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-01/Cargo.toml
new file mode 100644
index 000000000..1eb392dfa
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-01/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "shirt-company"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-01/output.txt b/src/doc/book/listings/ch13-functional-features/listing-13-01/output.txt
new file mode 100644
index 000000000..b64a4d8dc
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-01/output.txt
@@ -0,0 +1,6 @@
+$ cargo run
+   Compiling shirt-company v0.1.0 (file:///projects/shirt-company)
+    Finished dev [unoptimized + debuginfo] target(s) in 0.27s
+     Running `target/debug/shirt-company`
+The user with preference Some(Red) gets Red
+The user with preference None gets Blue
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-01/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-13-01/src/main.rs
new file mode 100644
index 000000000..2c87d6965
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-01/src/main.rs
@@ -0,0 +1,52 @@
+#[derive(Debug, PartialEq, Copy, Clone)]
+enum ShirtColor {
+    Red,
+    Blue,
+}
+
+struct Inventory {
+    shirts: Vec<ShirtColor>,
+}
+
+impl Inventory {
+    fn giveaway(&self, user_preference: Option<ShirtColor>) -> ShirtColor {
+        user_preference.unwrap_or_else(|| self.most_stocked())
+    }
+
+    fn most_stocked(&self) -> ShirtColor {
+        let mut num_red = 0;
+        let mut num_blue = 0;
+
+        for color in &self.shirts {
+            match color {
+                ShirtColor::Red => num_red += 1,
+                ShirtColor::Blue => num_blue += 1,
+            }
+        }
+        if num_red > num_blue {
+            ShirtColor::Red
+        } else {
+            ShirtColor::Blue
+        }
+    }
+}
+
+fn main() {
+    let store = Inventory {
+        shirts: vec![ShirtColor::Blue, ShirtColor::Red, ShirtColor::Blue],
+    };
+
+    let user_pref1 = Some(ShirtColor::Red);
+    let giveaway1 = store.giveaway(user_pref1);
+    println!(
+        "The user with preference {:?} gets {:?}",
+        user_pref1, giveaway1
+    );
+
+    let user_pref2 = None;
+    let giveaway2 = store.giveaway(user_pref2);
+    println!(
+        "The user with preference {:?} gets {:?}",
+        user_pref2, giveaway2
+    );
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-02/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-13-02/Cargo.lock
new file mode 100644
index 000000000..75ff09e51
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-02/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "workout-app"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-02/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-02/Cargo.toml
new file mode 100644
index 000000000..f09a737d4
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-02/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "workout-app"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-02/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-13-02/src/main.rs
new file mode 100644
index 000000000..b3f4cc2c2
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-02/src/main.rs
@@ -0,0 +1,33 @@
+use std::thread;
+use std::time::Duration;
+
+fn generate_workout(intensity: u32, random_number: u32) {
+    // ANCHOR: here
+    let expensive_closure = |num: u32| -> u32 {
+        println!("calculating slowly...");
+        thread::sleep(Duration::from_secs(2));
+        num
+    };
+    // ANCHOR_END: here
+
+    if intensity < 25 {
+        println!("Today, do {} pushups!", expensive_closure(intensity));
+        println!("Next, do {} situps!", expensive_closure(intensity));
+    } else {
+        if random_number == 3 {
+            println!("Take a break today! Remember to stay hydrated!");
+        } else {
+            println!(
+                "Today, run for {} minutes!",
+                expensive_closure(intensity)
+            );
+        }
+    }
+}
+
+fn main() {
+    let simulated_user_specified_value = 10;
+    let simulated_random_number = 7;
+
+    generate_workout(simulated_user_specified_value, simulated_random_number);
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-03/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-13-03/Cargo.lock
new file mode 100644
index 000000000..c190d3a41
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-03/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "closure-example"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-03/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-03/Cargo.toml
new file mode 100644
index 000000000..914c4cfaa
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-03/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "closure-example"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-03/output.txt b/src/doc/book/listings/ch13-functional-features/listing-13-03/output.txt
new file mode 100644
index 000000000..37d83618a
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-03/output.txt
@@ -0,0 +1,12 @@
+$ cargo run
+   Compiling closure-example v0.1.0 (file:///projects/closure-example)
+error[E0308]: mismatched types
+ --> src/main.rs:5:29
+  |
+5 |     let n = example_closure(5);
+  |                             ^- help: try using a conversion method: `.to_string()`
+  |                             |
+  |                             expected struct `String`, found integer
+
+For more information about this error, try `rustc --explain E0308`.
+error: could not compile `closure-example` due to previous error
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-03/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-13-03/src/main.rs
new file mode 100644
index 000000000..ebb2489bf
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-03/src/main.rs
@@ -0,0 +1,8 @@
+fn main() {
+    // ANCHOR: here
+    let example_closure = |x| x;
+
+    let s = example_closure(String::from("hello"));
+    let n = example_closure(5);
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-04/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-13-04/Cargo.lock
new file mode 100644
index 000000000..75ff09e51
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-04/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "workout-app"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-04/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-04/Cargo.toml
new file mode 100644
index 000000000..914c4cfaa
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-04/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "closure-example"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-04/output.txt b/src/doc/book/listings/ch13-functional-features/listing-13-04/output.txt
new file mode 100644
index 000000000..64d763b51
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-04/output.txt
@@ -0,0 +1,8 @@
+$ cargo run
+   Compiling closure-example v0.1.0 (file:///projects/closure-example)
+    Finished dev [unoptimized + debuginfo] target(s) in 0.43s
+     Running `target/debug/closure-example`
+Before defining closure: [1, 2, 3]
+Before calling closure: [1, 2, 3]
+From closure: [1, 2, 3]
+After calling closure: [1, 2, 3]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-04/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-13-04/src/main.rs
new file mode 100644
index 000000000..43b91bb30
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-04/src/main.rs
@@ -0,0 +1,10 @@
+fn main() {
+    let list = vec![1, 2, 3];
+    println!("Before defining closure: {:?}", list);
+
+    let only_borrows = || println!("From closure: {:?}", list);
+
+    println!("Before calling closure: {:?}", list);
+    only_borrows();
+    println!("After calling closure: {:?}", list);
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-05/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-13-05/Cargo.lock
new file mode 100644
index 000000000..75ff09e51
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-05/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "workout-app"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-05/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-05/Cargo.toml
new file mode 100644
index 000000000..914c4cfaa
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-05/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "closure-example"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-05/output.txt b/src/doc/book/listings/ch13-functional-features/listing-13-05/output.txt
new file mode 100644
index 000000000..ce0ad5e37
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-05/output.txt
@@ -0,0 +1,6 @@
+$ cargo run
+   Compiling closure-example v0.1.0 (file:///projects/closure-example)
+    Finished dev [unoptimized + debuginfo] target(s) in 0.43s
+     Running `target/debug/closure-example`
+Before defining closure: [1, 2, 3]
+After calling closure: [1, 2, 3, 7]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-05/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-13-05/src/main.rs
new file mode 100644
index 000000000..37f8130e2
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-05/src/main.rs
@@ -0,0 +1,9 @@
+fn main() {
+    let mut list = vec![1, 2, 3];
+    println!("Before defining closure: {:?}", list);
+
+    let mut borrows_mutably = || list.push(7);
+
+    borrows_mutably();
+    println!("After calling closure: {:?}", list);
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-06/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-06/Cargo.toml
new file mode 100644
index 000000000..8085ade0f
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-06/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "closure-example"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-06/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-13-06/src/main.rs
new file mode 100644
index 000000000..2c8e18c9f
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-06/src/main.rs
@@ -0,0 +1,10 @@
+use std::thread;
+
+fn main() {
+    let list = vec![1, 2, 3];
+    println!("Before defining closure: {:?}", list);
+
+    thread::spawn(move || println!("From thread: {:?}", list))
+        .join()
+        .unwrap();
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-07/.rustfmt.toml b/src/doc/book/listings/ch13-functional-features/listing-13-07/.rustfmt.toml
new file mode 100644
index 000000000..ee10c634b
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-07/.rustfmt.toml
@@ -0,0 +1,2 @@
+struct_lit_width = 50
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-07/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-07/Cargo.toml
new file mode 100644
index 000000000..4a279a450
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-07/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "rectangles"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-07/output.txt b/src/doc/book/listings/ch13-functional-features/listing-13-07/output.txt
new file mode 100644
index 000000000..f18fce46e
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-07/output.txt
@@ -0,0 +1,18 @@
+$ cargo run
+   Compiling rectangles v0.1.0 (file:///projects/rectangles)
+    Finished dev [unoptimized + debuginfo] target(s) in 0.41s
+     Running `target/debug/rectangles`
+[
+    Rectangle {
+        width: 3,
+        height: 5,
+    },
+    Rectangle {
+        width: 7,
+        height: 12,
+    },
+    Rectangle {
+        width: 10,
+        height: 1,
+    },
+]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-07/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-13-07/src/main.rs
new file mode 100644
index 000000000..73a25e5f9
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-07/src/main.rs
@@ -0,0 +1,16 @@
+#[derive(Debug)]
+struct Rectangle {
+    width: u32,
+    height: u32,
+}
+
+fn main() {
+    let mut list = [
+        Rectangle { width: 10, height: 1 },
+        Rectangle { width: 3, height: 5 },
+        Rectangle { width: 7, height: 12 },
+    ];
+
+    list.sort_by_key(|r| r.width);
+    println!("{:#?}", list);
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-08/.rustfmt.toml b/src/doc/book/listings/ch13-functional-features/listing-13-08/.rustfmt.toml
new file mode 100644
index 000000000..ee10c634b
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-08/.rustfmt.toml
@@ -0,0 +1,2 @@
+struct_lit_width = 50
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-08/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-08/Cargo.toml
new file mode 100644
index 000000000..703c9d977
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-08/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "rectangles"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-08/output.txt b/src/doc/book/listings/ch13-functional-features/listing-13-08/output.txt
new file mode 100644
index 000000000..7a39ac618
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-08/output.txt
@@ -0,0 +1,18 @@
+$ cargo run
+   Compiling rectangles v0.1.0 (file:///projects/rectangles)
+error[E0507]: cannot move out of `value`, a captured variable in an `FnMut` closure
+  --> src/main.rs:18:30
+   |
+15 |       let value = String::from("by key called");
+   |           ----- captured outer variable
+16 | 
+17 |       list.sort_by_key(|r| {
+   |  ______________________-
+18 | |         sort_operations.push(value);
+   | |                              ^^^^^ move occurs because `value` has type `String`, which does not implement the `Copy` trait
+19 | |         r.width
+20 | |     });
+   | |_____- captured by this `FnMut` closure
+
+For more information about this error, try `rustc --explain E0507`.
+error: could not compile `rectangles` due to previous error
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-08/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-13-08/src/main.rs
new file mode 100644
index 000000000..3b9c9cbdf
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-08/src/main.rs
@@ -0,0 +1,22 @@
+#[derive(Debug)]
+struct Rectangle {
+    width: u32,
+    height: u32,
+}
+
+fn main() {
+    let mut list = [
+        Rectangle { width: 10, height: 1 },
+        Rectangle { width: 3, height: 5 },
+        Rectangle { width: 7, height: 12 },
+    ];
+
+    let mut sort_operations = vec![];
+    let value = String::from("by key called");
+
+    list.sort_by_key(|r| {
+        sort_operations.push(value);
+        r.width
+    });
+    println!("{:#?}", list);
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-09/.rustfmt.toml b/src/doc/book/listings/ch13-functional-features/listing-13-09/.rustfmt.toml
new file mode 100644
index 000000000..ee10c634b
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-09/.rustfmt.toml
@@ -0,0 +1,2 @@
+struct_lit_width = 50
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-09/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-13-09/Cargo.lock
new file mode 100644
index 000000000..e090432bc
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-09/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "cacher"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-09/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-09/Cargo.toml
new file mode 100644
index 000000000..4a279a450
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-09/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "rectangles"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-09/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-13-09/src/main.rs
new file mode 100644
index 000000000..a60d6fd3f
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-09/src/main.rs
@@ -0,0 +1,20 @@
+#[derive(Debug)]
+struct Rectangle {
+    width: u32,
+    height: u32,
+}
+
+fn main() {
+    let mut list = [
+        Rectangle { width: 10, height: 1 },
+        Rectangle { width: 3, height: 5 },
+        Rectangle { width: 7, height: 12 },
+    ];
+
+    let mut num_sort_operations = 0;
+    list.sort_by_key(|r| {
+        num_sort_operations += 1;
+        r.width
+    });
+    println!("{:#?}, sorted in {num_sort_operations} operations", list);
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-10/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-13-10/Cargo.lock
new file mode 100644
index 000000000..e91eaa8d4
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-10/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "iterators"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-10/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-10/Cargo.toml
new file mode 100644
index 000000000..2652a8a1a
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-10/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "iterators"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-10/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-13-10/src/main.rs
new file mode 100644
index 000000000..55a0dd37e
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-10/src/main.rs
@@ -0,0 +1,7 @@
+fn main() {
+    // ANCHOR: here
+    let v1 = vec![1, 2, 3];
+
+    let v1_iter = v1.iter();
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-11/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-13-11/Cargo.lock
new file mode 100644
index 000000000..e91eaa8d4
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-11/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "iterators"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-11/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-11/Cargo.toml
new file mode 100644
index 000000000..2652a8a1a
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-11/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "iterators"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-11/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-13-11/src/main.rs
new file mode 100644
index 000000000..712aff408
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-11/src/main.rs
@@ -0,0 +1,11 @@
+fn main() {
+    // ANCHOR: here
+    let v1 = vec![1, 2, 3];
+
+    let v1_iter = v1.iter();
+
+    for val in v1_iter {
+        println!("Got: {}", val);
+    }
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-12/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-13-12/Cargo.lock
new file mode 100644
index 000000000..e91eaa8d4
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-12/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "iterators"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-12/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-12/Cargo.toml
new file mode 100644
index 000000000..2652a8a1a
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-12/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "iterators"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-12/src/lib.rs b/src/doc/book/listings/ch13-functional-features/listing-13-12/src/lib.rs
new file mode 100644
index 000000000..758284044
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-12/src/lib.rs
@@ -0,0 +1,16 @@
+#[cfg(test)]
+mod tests {
+    // ANCHOR: here
+    #[test]
+    fn iterator_demonstration() {
+        let v1 = vec![1, 2, 3];
+
+        let mut v1_iter = v1.iter();
+
+        assert_eq!(v1_iter.next(), Some(&1));
+        assert_eq!(v1_iter.next(), Some(&2));
+        assert_eq!(v1_iter.next(), Some(&3));
+        assert_eq!(v1_iter.next(), None);
+    }
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-13/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-13-13/Cargo.lock
new file mode 100644
index 000000000..e91eaa8d4
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-13/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "iterators"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-13/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-13/Cargo.toml
new file mode 100644
index 000000000..2652a8a1a
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-13/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "iterators"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-13/src/lib.rs b/src/doc/book/listings/ch13-functional-features/listing-13-13/src/lib.rs
new file mode 100644
index 000000000..d1cb54d0a
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-13/src/lib.rs
@@ -0,0 +1,15 @@
+#[cfg(test)]
+mod tests {
+    // ANCHOR: here
+    #[test]
+    fn iterator_sum() {
+        let v1 = vec![1, 2, 3];
+
+        let v1_iter = v1.iter();
+
+        let total: i32 = v1_iter.sum();
+
+        assert_eq!(total, 6);
+    }
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-14/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-13-14/Cargo.lock
new file mode 100644
index 000000000..e91eaa8d4
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-14/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "iterators"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-14/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-14/Cargo.toml
new file mode 100644
index 000000000..2652a8a1a
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-14/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "iterators"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-14/output.txt b/src/doc/book/listings/ch13-functional-features/listing-13-14/output.txt
new file mode 100644
index 000000000..228c764ed
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-14/output.txt
@@ -0,0 +1,14 @@
+$ cargo run
+   Compiling iterators v0.1.0 (file:///projects/iterators)
+warning: unused `Map` that must be used
+ --> src/main.rs:4:5
+  |
+4 |     v1.iter().map(|x| x + 1);
+  |     ^^^^^^^^^^^^^^^^^^^^^^^^^
+  |
+  = note: `#[warn(unused_must_use)]` on by default
+  = note: iterators are lazy and do nothing unless consumed
+
+warning: `iterators` (bin "iterators") generated 1 warning
+    Finished dev [unoptimized + debuginfo] target(s) in 0.47s
+     Running `target/debug/iterators`
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-14/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-13-14/src/main.rs
new file mode 100644
index 000000000..62a68be9b
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-14/src/main.rs
@@ -0,0 +1,7 @@
+fn main() {
+    // ANCHOR: here
+    let v1: Vec<i32> = vec![1, 2, 3];
+
+    v1.iter().map(|x| x + 1);
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-15/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-13-15/Cargo.lock
new file mode 100644
index 000000000..e91eaa8d4
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-15/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "iterators"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-15/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-15/Cargo.toml
new file mode 100644
index 000000000..2652a8a1a
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-15/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "iterators"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-15/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-13-15/src/main.rs
new file mode 100644
index 000000000..db9025d6f
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-15/src/main.rs
@@ -0,0 +1,9 @@
+fn main() {
+    // ANCHOR: here
+    let v1: Vec<i32> = vec![1, 2, 3];
+
+    let v2: Vec<_> = v1.iter().map(|x| x + 1).collect();
+
+    assert_eq!(v2, vec![2, 3, 4]);
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-16/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-13-16/Cargo.lock
new file mode 100644
index 000000000..0b15e2157
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-16/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "shoe_size"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-16/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-16/Cargo.toml
new file mode 100644
index 000000000..cc803776b
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-16/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "shoe_size"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-16/src/lib.rs b/src/doc/book/listings/ch13-functional-features/listing-13-16/src/lib.rs
new file mode 100644
index 000000000..281c3c9e4
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-16/src/lib.rs
@@ -0,0 +1,48 @@
+#[derive(PartialEq, Debug)]
+struct Shoe {
+    size: u32,
+    style: String,
+}
+
+fn shoes_in_size(shoes: Vec<Shoe>, shoe_size: u32) -> Vec<Shoe> {
+    shoes.into_iter().filter(|s| s.size == shoe_size).collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn filters_by_size() {
+        let shoes = vec![
+            Shoe {
+                size: 10,
+                style: String::from("sneaker"),
+            },
+            Shoe {
+                size: 13,
+                style: String::from("sandal"),
+            },
+            Shoe {
+                size: 10,
+                style: String::from("boot"),
+            },
+        ];
+
+        let in_my_size = shoes_in_size(shoes, 10);
+
+        assert_eq!(
+            in_my_size,
+            vec![
+                Shoe {
+                    size: 10,
+                    style: String::from("sneaker")
+                },
+                Shoe {
+                    size: 10,
+                    style: String::from("boot")
+                },
+            ]
+        );
+    }
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-18/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-13-18/Cargo.lock
new file mode 100644
index 000000000..88bf82d16
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-18/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "minigrep"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-18/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-18/Cargo.toml
new file mode 100644
index 000000000..64c2a3f52
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-18/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "minigrep"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-18/poem.txt b/src/doc/book/listings/ch13-functional-features/listing-13-18/poem.txt
new file mode 100644
index 000000000..870752731
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-18/poem.txt
@@ -0,0 +1,9 @@
+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!
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-18/src/lib.rs b/src/doc/book/listings/ch13-functional-features/listing-13-18/src/lib.rs
new file mode 100644
index 000000000..292b09789
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-18/src/lib.rs
@@ -0,0 +1,104 @@
+use std::env;
+use std::error::Error;
+use std::fs;
+
+pub struct Config {
+    pub query: String,
+    pub file_path: String,
+    pub ignore_case: bool,
+}
+
+impl Config {
+    pub fn build(args: &[String]) -> Result<Config, &'static str> {
+        if args.len() < 3 {
+            return Err("not enough arguments");
+        }
+
+        let query = args[1].clone();
+        let file_path = args[2].clone();
+
+        let ignore_case = env::var("IGNORE_CASE").is_ok();
+
+        Ok(Config {
+            query,
+            file_path,
+            ignore_case,
+        })
+    }
+}
+
+pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
+    let contents = fs::read_to_string(config.file_path)?;
+
+    let results = if config.ignore_case {
+        search_case_insensitive(&config.query, &contents)
+    } else {
+        search(&config.query, &contents)
+    };
+
+    for line in results {
+        println!("{line}");
+    }
+
+    Ok(())
+}
+
+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 query = query.to_lowercase();
+    let mut results = Vec::new();
+
+    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)
+        );
+    }
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-18/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-13-18/src/main.rs
new file mode 100644
index 000000000..40109ef63
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-18/src/main.rs
@@ -0,0 +1,22 @@
+use std::env;
+use std::process;
+
+use minigrep::Config;
+
+// ANCHOR: here
+fn main() {
+    let config = Config::build(env::args()).unwrap_or_else(|err| {
+        eprintln!("Problem parsing arguments: {err}");
+        process::exit(1);
+    });
+
+    // --snip--
+    // ANCHOR_END: here
+
+    if let Err(e) = minigrep::run(config) {
+        eprintln!("Application error: {e}");
+        process::exit(1);
+    }
+    // ANCHOR: here
+}
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-19/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-13-19/Cargo.lock
new file mode 100644
index 000000000..88bf82d16
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-19/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "minigrep"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-19/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-19/Cargo.toml
new file mode 100644
index 000000000..64c2a3f52
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-19/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "minigrep"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-19/poem.txt b/src/doc/book/listings/ch13-functional-features/listing-13-19/poem.txt
new file mode 100644
index 000000000..870752731
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-19/poem.txt
@@ -0,0 +1,9 @@
+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!
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-19/src/lib.rs b/src/doc/book/listings/ch13-functional-features/listing-13-19/src/lib.rs
new file mode 100644
index 000000000..79ae2b8f6
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-19/src/lib.rs
@@ -0,0 +1,109 @@
+use std::env;
+use std::error::Error;
+use std::fs;
+
+pub struct Config {
+    pub query: String,
+    pub file_path: String,
+    pub ignore_case: bool,
+}
+
+// ANCHOR: here
+impl Config {
+    pub fn build(
+        mut args: impl Iterator<Item = String>,
+    ) -> Result<Config, &'static str> {
+        // --snip--
+        // ANCHOR_END: here
+        if args.len() < 3 {
+            return Err("not enough arguments");
+        }
+
+        let query = args[1].clone();
+        let file_path = args[2].clone();
+
+        let ignore_case = env::var("IGNORE_CASE").is_ok();
+
+        Ok(Config {
+            query,
+            file_path,
+            ignore_case,
+        })
+    }
+}
+
+pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
+    let contents = fs::read_to_string(config.file_path)?;
+
+    let results = if config.ignore_case {
+        search_case_insensitive(&config.query, &contents)
+    } else {
+        search(&config.query, &contents)
+    };
+
+    for line in results {
+        println!("{line}");
+    }
+
+    Ok(())
+}
+
+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 query = query.to_lowercase();
+    let mut results = Vec::new();
+
+    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)
+        );
+    }
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-19/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-13-19/src/main.rs
new file mode 100644
index 000000000..9ac022545
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-19/src/main.rs
@@ -0,0 +1,16 @@
+use std::env;
+use std::process;
+
+use minigrep::Config;
+
+fn main() {
+    let config = Config::build(env::args()).unwrap_or_else(|err| {
+        eprintln!("Problem parsing arguments: {err}");
+        process::exit(1);
+    });
+
+    if let Err(e) = minigrep::run(config) {
+        eprintln!("Application error: {e}");
+        process::exit(1);
+    }
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-20/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-13-20/Cargo.lock
new file mode 100644
index 000000000..88bf82d16
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-20/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "minigrep"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-20/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-20/Cargo.toml
new file mode 100644
index 000000000..64c2a3f52
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-20/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "minigrep"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-20/poem.txt b/src/doc/book/listings/ch13-functional-features/listing-13-20/poem.txt
new file mode 100644
index 000000000..870752731
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-20/poem.txt
@@ -0,0 +1,9 @@
+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!
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-20/src/lib.rs b/src/doc/book/listings/ch13-functional-features/listing-13-20/src/lib.rs
new file mode 100644
index 000000000..4410964a7
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-20/src/lib.rs
@@ -0,0 +1,113 @@
+use std::env;
+use std::error::Error;
+use std::fs;
+
+pub struct Config {
+    pub query: String,
+    pub file_path: String,
+    pub ignore_case: bool,
+}
+
+// ANCHOR: here
+impl Config {
+    pub fn build(
+        mut args: impl Iterator<Item = String>,
+    ) -> Result<Config, &'static str> {
+        args.next();
+
+        let query = match args.next() {
+            Some(arg) => arg,
+            None => return Err("Didn't get a query string"),
+        };
+
+        let file_path = match args.next() {
+            Some(arg) => arg,
+            None => return Err("Didn't get a file path"),
+        };
+
+        let ignore_case = env::var("IGNORE_CASE").is_ok();
+
+        Ok(Config {
+            query,
+            file_path,
+            ignore_case,
+        })
+    }
+}
+// ANCHOR_END: here
+
+pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
+    let contents = fs::read_to_string(config.file_path)?;
+
+    let results = if config.ignore_case {
+        search_case_insensitive(&config.query, &contents)
+    } else {
+        search(&config.query, &contents)
+    };
+
+    for line in results {
+        println!("{line}");
+    }
+
+    Ok(())
+}
+
+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 query = query.to_lowercase();
+    let mut results = Vec::new();
+
+    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)
+        );
+    }
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-20/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-13-20/src/main.rs
new file mode 100644
index 000000000..9ac022545
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-20/src/main.rs
@@ -0,0 +1,16 @@
+use std::env;
+use std::process;
+
+use minigrep::Config;
+
+fn main() {
+    let config = Config::build(env::args()).unwrap_or_else(|err| {
+        eprintln!("Problem parsing arguments: {err}");
+        process::exit(1);
+    });
+
+    if let Err(e) = minigrep::run(config) {
+        eprintln!("Application error: {e}");
+        process::exit(1);
+    }
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-22/Cargo.lock b/src/doc/book/listings/ch13-functional-features/listing-13-22/Cargo.lock
new file mode 100644
index 000000000..88bf82d16
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-22/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "minigrep"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-22/Cargo.toml b/src/doc/book/listings/ch13-functional-features/listing-13-22/Cargo.toml
new file mode 100644
index 000000000..64c2a3f52
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-22/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "minigrep"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-22/poem.txt b/src/doc/book/listings/ch13-functional-features/listing-13-22/poem.txt
new file mode 100644
index 000000000..870752731
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-22/poem.txt
@@ -0,0 +1,9 @@
+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!
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-22/src/lib.rs b/src/doc/book/listings/ch13-functional-features/listing-13-22/src/lib.rs
new file mode 100644
index 000000000..d694669b4
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-22/src/lib.rs
@@ -0,0 +1,108 @@
+use std::env;
+use std::error::Error;
+use std::fs;
+
+pub struct Config {
+    pub query: String,
+    pub file_path: String,
+    pub ignore_case: bool,
+}
+
+impl Config {
+    pub fn build(
+        mut args: impl Iterator<Item = String>,
+    ) -> Result<Config, &'static str> {
+        args.next();
+
+        let query = match args.next() {
+            Some(arg) => arg,
+            None => return Err("Didn't get a query string"),
+        };
+
+        let file_path = match args.next() {
+            Some(arg) => arg,
+            None => return Err("Didn't get a file path"),
+        };
+
+        let ignore_case = env::var("IGNORE_CASE").is_ok();
+
+        Ok(Config {
+            query,
+            file_path,
+            ignore_case,
+        })
+    }
+}
+
+pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
+    let contents = fs::read_to_string(config.file_path)?;
+
+    let results = if config.ignore_case {
+        search_case_insensitive(&config.query, &contents)
+    } else {
+        search(&config.query, &contents)
+    };
+
+    for line in results {
+        println!("{line}");
+    }
+
+    Ok(())
+}
+
+// ANCHOR: here
+pub fn search<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
+    contents
+        .lines()
+        .filter(|line| line.contains(query))
+        .collect()
+}
+// ANCHOR_END: here
+
+pub fn search_case_insensitive<'a>(
+    query: &str,
+    contents: &'a str,
+) -> Vec<&'a str> {
+    let query = query.to_lowercase();
+    let mut results = Vec::new();
+
+    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)
+        );
+    }
+}
diff --git a/src/doc/book/listings/ch13-functional-features/listing-13-22/src/main.rs b/src/doc/book/listings/ch13-functional-features/listing-13-22/src/main.rs
new file mode 100644
index 000000000..9ac022545
--- /dev/null
+++ b/src/doc/book/listings/ch13-functional-features/listing-13-22/src/main.rs
@@ -0,0 +1,16 @@
+use std::env;
+use std::process;
+
+use minigrep::Config;
+
+fn main() {
+    let config = Config::build(env::args()).unwrap_or_else(|err| {
+        eprintln!("Problem parsing arguments: {err}");
+        process::exit(1);
+    });
+
+    if let Err(e) = minigrep::run(config) {
+        eprintln!("Application error: {e}");
+        process::exit(1);
+    }
+}