From a8a40420b4106d66bdf1c447388404896dccd494 Mon Sep 17 00:00:00 2001
From: Jordan Gong <jordan.gong@protonmail.com>
Date: Wed, 2 Sep 2020 19:37:03 +0800
Subject: Generalize redundant code

---
 generics/.gitignore  | 18 ++++++++++++++++++
 generics/Cargo.toml  |  9 +++++++++
 generics/src/main.rs | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 79 insertions(+)
 create mode 100644 generics/.gitignore
 create mode 100644 generics/Cargo.toml
 create mode 100644 generics/src/main.rs

diff --git a/generics/.gitignore b/generics/.gitignore
new file mode 100644
index 0000000..e629269
--- /dev/null
+++ b/generics/.gitignore
@@ -0,0 +1,18 @@
+
+# Created by https://www.toptal.com/developers/gitignore/api/rust
+# Edit at https://www.toptal.com/developers/gitignore?templates=rust
+
+### Rust ###
+# Generated by Cargo
+# will have compiled files and executables
+/target/
+
+# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
+# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
+Cargo.lock
+
+# These are backup files generated by rustfmt
+**/*.rs.bk
+
+# End of https://www.toptal.com/developers/gitignore/api/rust
+
diff --git a/generics/Cargo.toml b/generics/Cargo.toml
new file mode 100644
index 0000000..5d46e6b
--- /dev/null
+++ b/generics/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "generics"
+version = "0.1.0"
+authors = ["Jordan Gong <jordan.gong@protonmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/generics/src/main.rs b/generics/src/main.rs
new file mode 100644
index 0000000..776f563
--- /dev/null
+++ b/generics/src/main.rs
@@ -0,0 +1,52 @@
+fn main() {
+    {
+        struct Point<T> {
+            x: T,
+            y: T,
+        }
+
+        impl<T> Point<T> {
+            fn x(&self) -> &T {
+                &self.x
+            }
+        }
+
+        // implement a particular concrete type
+        impl Point<f32> {
+            fn distance_from_origin(&self) -> f32 {
+                (self.x.powi(2) + self.y.powi(2)).sqrt()
+            }
+        }
+
+        let p = Point { x: 5, y: 10 };
+        println!("p.x = {}", p.x());
+
+        let p2 = Point { x: 1.0, y: 4.0 };
+        println!(
+            "distance between p2 and origin: {}",
+            p2.distance_from_origin()
+        );
+    }
+    {
+        struct Point<T, U> {
+            x: T,
+            y: U,
+        }
+
+        impl<T, U> Point<T, U> {
+            fn mixup<V, W>(self, other: Point<V, W>) -> Point<T, W> {
+                Point {
+                    x: self.x,
+                    y: other.y,
+                }
+            }
+        }
+
+        let p1 = Point { x: 5, y: 10.4 };
+        let p2 = Point { x: "Hello", y: 'c' };
+
+        let p3 = p1.mixup(p2);
+
+        println!("p3.x = {}, p3.y = {}", p3.x, p3.y);
+    }
+}
-- 
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