Start writing a part on closures

[rust-101.git] / src / part10.rs

diff --git a/src/part10.rs b/src/part10.rs
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+// Rust-101, Part 09: Closures (WIP)
+// =================================
+
+use std::io::prelude::*;
+use std::io;
+
+use part05::BigInt;
+
+trait Action {
+    fn do_action(&mut self, digit: u64);
+}
+
+impl BigInt {
+    fn act_v1<A: Action>(&self, mut a: A) {
+        for digit in self {
+            a.do_action(digit);
+        }
+    }
+}
+
+struct PrintWithString {
+    prefix: String,
+}
+
+impl Action for PrintWithString {
+    fn do_action(&mut self, digit: u64) {
+        println!("{}{}", self.prefix, digit);
+    }
+}
+
+fn read_one_line() -> String {
+    println!("Please enter a line of text.");
+    let mut stdin = io::stdin();
+    let mut prefix = "".to_string();
+    stdin.read_line(&mut prefix).unwrap();
+    prefix
+}
+
+pub fn main_v1() {
+    let prefix = read_one_line();
+    let my_action = PrintWithString { prefix: prefix };
+    let bignum = BigInt::new(1 << 63) + BigInt::new(1 << 16) + BigInt::new(1 << 63);
+    bignum.act_v1(my_action);
+}
+
+impl BigInt {
+    fn act<A: FnMut(u64)>(&self, mut a: A) {
+        for digit in self {
+            a(digit);
+        }
+    }
+}
+
+pub fn main() {
+    let prefix = read_one_line();
+    let bignum = BigInt::new(1 << 63) + BigInt::new(1 << 16) + BigInt::new(1 << 63);
+    bignum.act(|digit| println!("{}{}", prefix, digit) );
+}
+
+//@ [index](main.html) | [previous](part08.html) | [next](main.html)