Added functional and implemented iterators in minigrep.

4 files changed, 194 insertions, 74 deletions

diff --git a/functional/src/main.rs b/functional/src/main.rs
index 4fbc447..7749e58 100644
--- a/functional/src/main.rs
+++ b/functional/src/main.rs
@@ -1,50 +1,188 @@
-use std::thread;
-use std::time::Duration;
+//use std::thread;
+//use std::time::Duration;
+//
+//struct Cacher<T>
+//    where T: Fn(u32) -> u32
+//{
+//    calculation: T,
+//    value: Option<u32>,
+//}
+//
+//impl<T> Cacher<T>
+//    where T: Fn(u32) -> u32
+//{
+//    fn new (calculation: T) -> Cacher<T> {
+//        Cacher {
+//            calculation,
+//            value: None,
+//        }
+//    }
+//
+//    fn value(&mut self, arg: u32) -> u32 {
+//        match self.value {
+//            Some(v) => v,
+//            None => {
+//                let v = (self.calculation)(arg);
+//                self.value = Some(v);
+//                v
+//            },
+//        }
+//    }
+//}
+//
+//fn main() {
+//    let simulated_user_specified_value = 26;
+//    let simulated_random_number = 3;
+//
+//    generate_workout(
+//        simulated_user_specified_value,
+//        simulated_random_number
+//    );
+//}
+//
+//fn generate_workout(intensity: u32, random_number: u32) {
+//    let mut expensive_result = Cacher::new(|num| {
+//        println!("calculating slowly...");
+//        thread::sleep(Duration::from_secs(2));
+//        num
+//    });
+//
+//    if intensity < 25 {
+//        println!(
+//            "Today, do {} pushups!",
+//            expensive_result.value(intensity)
+//        );
+//        println!(
+//            "Next, do {} situps!",
+//            expensive_result.value(intensity)
+//        );
+//    }
+//    else {
+//        if random_number == 3 {
+//            println!("Take a break today! Remember to stay hydrated!");
+//        }
+//        else {
+//            println!(
+//                "Today, run for {} minutes!",
+//                expensive_result.value(intensity)
+//            );
+//        }
+//    }
+//}
+//
+
+
 
-struct Cacher<T>
-    where T: Fn(u32) -> u32
-{
-    calculation: T,
-    value: Option<u32>,
-}
 
 fn main() {
-    let simulated_user_specified_value = 10;
-    let simulated_random_number = 7;
+    let v1 = vec![1, 2, 3];
+    let v1_iter = v1.iter();
+
+    for val in v1_iter {
+        dbg!(val);
+    }
+}
+
+#[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);
+}
+
+#[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);
+}
+
+#[test]
+fn iterator_map() {
+    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]);
+}
+
+
 
-    generate_workout(
-        simulated_user_specified_value,
-        simulated_random_number
+#[derive(PartialEq, Debug)]
+struct Shoe {
+    size: i32,
+    style: String,
+}
+
+fn shoes_in_my_size(shoes: Vec<Shoe>, shoe_size: i32) -> Vec<Shoe> {
+    shoes.into_iter()
+        .filter(|s| s.size == shoe_size)
+        .collect()
+}
+
+#[test]
+fn filters_by_size() {
+    let shoes = vec![
+        Shoe { size: 10, style: String::from("sneaker") },
+        Shoe { size: 10, style: String::from("boot") },
+        Shoe { size: 13, style: String::from("sandal") },
+    ];
+
+    let in_my_size = shoes_in_my_size(shoes, 10);
+
+    assert_eq!(
+        in_my_size,
+        vec![
+            Shoe { size: 10, style: String::from("sneaker") },
+            Shoe { size: 10, style: String::from("boot") },
+        ]
     );
 }
 
-fn generate_workout(intensity: u32, random_number: u32) {
-    let expensive_closure = |num| {
-        println!("calculating slowly...");
-        thread::sleep(Duration::from_secs(2));
-        num
-    };
-
-    if intensity < 25 {
-        println!(
-            "Today, do {} pushups!",
-            expensive_closure(intensity)
-        );
-        println!(
-            "Next, do {} situps!",
-            expensive_closure(intensity)
-        );
+struct Counter {
+    count: u32,
+}
+
+impl Counter {
+    fn new() -> Counter {
+        Counter { count: 0 }
     }
-    else {
-        if random_number == 3 {
-            println!("Take a break today! Remember to stay hydrated!");
+}
+
+impl Iterator for Counter {
+    type Item = u32;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.count += 1;
+
+        if self.count < 6 {
+            Some(self.count)
         }
         else {
-            println!(
-                "Today, run for {} minutes!",
-                expensive_closure(intensity)
-            );
+            None
         }
     }
 }
 
+#[test]
+fn calling_next_directly() {
+    let mut counter = Counter::new();
+    assert_eq!(counter.next(), Some(1));
+    assert_eq!(counter.next(), Some(2));
+    assert_eq!(counter.next(), Some(3));
+    assert_eq!(counter.next(), Some(4));
+    assert_eq!(counter.next(), Some(5));
+    assert_eq!(counter.next(), None);
+}
+
+#[test]
+fn using_other_iterator_trait_methods() {
+    let sum: u32 = Counter::new().zip(Counter::new().skip(1))
+        .map(|(a, b)| a * b)
+        .filter(|x| x % 3 == 0)
+        .sum();
+    assert_eq!(18, sum);
+}
diff --git a/minigrep/Cargo.toml b/minigrep/Cargo.toml
index 6a8174c..09021c1 100644
--- a/minigrep/Cargo.toml
+++ b/minigrep/Cargo.toml
@@ -5,3 +5,4 @@ authors = ["Adam Carpenter <53hornet@gmail.com>"]
 edition = "2018"
 
 [dependencies]
+
diff --git a/minigrep/src/lib.rs b/minigrep/src/lib.rs
index bf7118f..bb8b4d7 100644
--- a/minigrep/src/lib.rs
+++ b/minigrep/src/lib.rs
@@ -10,26 +10,20 @@ pub struct Config {
 
 impl Config {
 
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(mut args: std::env::Args) -> Result<Config, &'static str> {
+        args.next();
 
-        if args.len() < 3 {
-            return Err("Not enough arguments.");
-        }
+        let query = match args.next() {
+            Some(arg) => arg,
+            None => return Err("Didn't get a query string"),
+        };
 
-        let query = args[1].clone();
-        let filename = args[2].clone();
-        let mut case_sensitive = env::var("CASE_INSENSITIVE").is_err();
-
-        // override environment variable if cli arg is present
-        if args.len() > 3 {
-            if args[3] == "-s" {
-                case_sensitive = true;
-            }
-            else if args[3] == "-i" {
-                case_sensitive = false;
-            }
-        }
+        let filename = match args.next() {
+            Some(arg) => arg,
+            None => return Err("Didn't get a filename"),
+        };
 
+        let case_sensitive = env::var("CASE_INSENSITIVE").is_err();
 
         Ok(Config { query, filename, case_sensitive })
     }
@@ -54,28 +48,16 @@ pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
 }
 
 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
+    contents.lines()
+        .filter(|line| line.contains(query))
+        .collect()
 }
 
 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
+    contents.lines()
+        .filter(|line| line.to_lowercase()
+                .contains(&query.to_lowercase()))
+        .collect()
 }
 
 #[cfg(test)]
diff --git a/minigrep/src/main.rs b/minigrep/src/main.rs
index 3cec101..c752da1 100644
--- a/minigrep/src/main.rs
+++ b/minigrep/src/main.rs
@@ -5,8 +5,7 @@ use minigrep;
 use minigrep::Config;
 
 fn main() {
-    let args: Vec<String> = env::args().collect();
-    let config = Config::new(&args).unwrap_or_else(|err| {
+    let config = Config::new(env::args()).unwrap_or_else(|err| {
         eprintln!("Problem parsing arguments: {}", err);
         process::exit(1);
     });