Remaining flow control in RBE

rustbyexample/flow_control.d/if_let.rs

@@ -0,0 +1,25 @@
+fn main() {
+    let number = Some(7);
+    let letter: Option<i32> = None;
+    let emoticon: Option<i32> = None;
+
+    if let Some(i) = number {
+        println!("Matched {:?}!", i);
+    }
+
+    if let Some(i) = letter {
+        println!("Matched {:?}!", i);
+    } else {
+        println!("Didn't match a number. Let's go with a letter!");
+    }
+
+    let i_like_letters = false;
+
+    if let Some(i) = emoticon {
+        println!("Matched {:?}!", i);
+    } else if i_like_letters {
+        println!("Didn't match a number. Let's go with a letter!");
+    } else {
+        println!("I don't like letters. Let's go with an emoticon :)!");
+    }
+}

rustbyexample/flow_control.d/if_let2.rs

@@ -0,0 +1,27 @@
+enum Foo {
+    Bar,
+    Baz,
+    Qux(u32),
+}
+
+fn main() {
+    let a = Foo::Bar;
+    let b = Foo::Baz;
+    let c = Foo::Qux(100);
+
+    if let Foo::Bar = a {
+        println!("a is a foobar");
+    }
+
+    if let Foo::Bar = b {
+        println!("b is foobar");
+    }
+
+    if let Foo::Qux(value) = c {
+        println!("c is {}", value);
+    }
+
+    if let Foo::Qux(value @ 100) = c {
+        println!("c is one hundred (value: {:?})", value);
+    }
+}

rustbyexample/flow_control.d/if_let3.rs

@@ -0,0 +1,11 @@
+enum Foo {
+    Bar,
+}
+
+fn main() {
+    let a = Foo::Bar;
+
+    if let Foo::Bar = a {
+        println!("a is foobar");
+    }
+}

rustbyexample/flow_control.d/let_else.rs

@@ -0,0 +1,16 @@
+use std::str::FromStr;
+
+fn get_count_item(s: &str) -> (u64, &str) {
+    let mut it = s.split(' ');
+    let (Some(count_str), Some(item)) = (it.next(), it.next()) else {
+        panic!("Can't segment count item pair: '{s}'");
+    };
+    let Ok(count) = u64::from_str(count_str) else {
+        panic!("Can't parse integer: '{count_str}'");
+    };
+    (count, item)
+}
+
+fn main() {
+    assert_eq!(get_count_item("3 chairs"), (3, "chairs"));
+}

rustbyexample/flow_control.d/while_let.rs

@@ -0,0 +1,13 @@
+fn main() {
+    let mut optional = Some(0);
+
+    while let Some(i) = optional {
+        if i > 9 {
+            println!("Greater than 9, quit!");
+            optional = None;
+        } else {
+            println!("`i` is `{:?}`. Try again.", i);
+            optional = Some(i + 1);
+        }
+    }
+}