Enums

Author: danjambur

Cargo.toml

@@ -10,6 +10,8 @@ members = [
     "./ownership",
     "./return_ownership",
     "./structs",
-    "./structs_rectangle"
+    "./structs_rectangle",
+    "./enums",
+    "./enums_messages",
 ]
 

enums/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "enums"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

enums/src/main.rs

@@ -0,0 +1,16 @@
+enum IPAddrKind {
+    V4,
+    V6,
+}
+
+enum IpAddr {
+    // IPV4 will always have 4 numbers between 0 and 255.
+    // Each variant in an enum can have a different type.
+    // Which is what we can't do with a struct
+    V4(u8, u8, u8, u8),
+    V6(String),
+}
+fn main() {
+    let home = IpAddr::V4(127, 0, 0, 1);
+    let loopback = IpAddr::V6(String::from("::1"));
+}

enums_messages/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "enums_messages"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

enums_messages/src/main.rs

@@ -0,0 +1,28 @@
+fn main() {
+    // This is quite similar to a struct,
+    // except we don't use the struct keyword,
+    //  and all the variants are grouped together under the message Type
+
+    fn call(&self) {
+        // whatever
+    }
+
+    enum Message {
+        Quit,                        // Has no data associated
+        Move { x: i32, y: i32 },     // has named fields, like a struct
+        Write(String),               // Includes a single String
+        ChangeColour(i32, i32, i32), // Includes 3 i32 vals
+    }
+    // This is much nicer than;
+
+    struct QuitMessage; // unit struct
+    struct MoveMessage {
+        x: i32,
+        y: i32,
+    };
+    struct WriteMessage(String); // Tuple struct
+    struct ChangeColourMessage(i32, i32, i32); // Tuple struct
+
+    let m = Message::Write(String::from("Wassup"));
+    m.call()
+}