From 68d838f8b6ad1d02e8255be56bf8f4744d2fbaf0 Mon Sep 17 00:00:00 2001
From: Lukas Kalbertodt <lukas.kalbertodt@gmail.com>
Date: Mon, 9 Jan 2017 18:43:34 +0100
Subject: [PATCH] Add solution sheet9

---
 aufgaben/sheet9/sol1/try-opt.rs | 36 ++++++++++++++++++++++++++++
 aufgaben/sheet9/sol2/fmt.rs     | 42 +++++++++++++++++++++++++++++++++
 aufgaben/sheet9/sol3/map.rs     | 15 ++++++++++++
 3 files changed, 93 insertions(+)
 create mode 100755 aufgaben/sheet9/sol1/try-opt.rs
 create mode 100755 aufgaben/sheet9/sol2/fmt.rs
 create mode 100755 aufgaben/sheet9/sol3/map.rs

diff --git a/aufgaben/sheet9/sol1/try-opt.rs b/aufgaben/sheet9/sol1/try-opt.rs
new file mode 100755
index 0000000..d30015b
--- /dev/null
+++ b/aufgaben/sheet9/sol1/try-opt.rs
@@ -0,0 +1,36 @@
+// If we would make this public for everyone, we would need to use absolute
+// paths!
+macro_rules! try_opt {
+    ($e:expr) => {
+        match $e {
+            ::std::option::Option::Some(v) => v,
+            None => return None,
+        }
+    }
+}
+
+macro_rules! name {
+    () => ($crate)
+}
+
+fn main() {
+    println!("{:?}", name!());
+    println!("consistent: {:?}", is_home_consistent());
+    println!("dummy: {:?}", foo());
+}
+
+fn foo() -> Option<u8> {
+    let a: u8 = try_opt!(Some(50));
+    let b = try_opt!(a.checked_mul(6));
+
+    Some(b / 2)
+}
+
+fn is_home_consistent() -> Option<bool> {
+    use std::env;
+
+    let home_dir = try_opt!(env::home_dir());
+    let home_var = try_opt!(env::var_os("HOME"));
+
+    Some(home_dir == home_var)
+}
diff --git a/aufgaben/sheet9/sol2/fmt.rs b/aufgaben/sheet9/sol2/fmt.rs
new file mode 100755
index 0000000..4cf5548
--- /dev/null
+++ b/aufgaben/sheet9/sol2/fmt.rs
@@ -0,0 +1,42 @@
+struct LoveMachine<T> {
+    inner: T,
+}
+
+impl<T> LoveMachine<T> {
+    pub fn new(t: T) -> Self {
+        LoveMachine {
+            inner: t,
+        }
+    }
+}
+
+macro_rules! impl_fmt {
+    ($fmt_trait:ident, $fmt_str:expr) => {
+        impl<T> ::std::fmt::$fmt_trait for LoveMachine<T>
+            where T: ::std::fmt::$fmt_trait
+        {
+            fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+                write!(f, concat!("♥", $fmt_str, "♥"), self.inner)
+            }
+        }
+    }
+}
+
+impl_fmt!(Display,  "{}");
+impl_fmt!(Debug,    "{:?}");
+impl_fmt!(Octal,    "{:o}");
+impl_fmt!(LowerHex, "{:x}");
+impl_fmt!(UpperHex, "{:X}");
+impl_fmt!(Binary,   "{:b}");
+impl_fmt!(LowerExp, "{:e}");
+impl_fmt!(UpperExp, "{:E}");
+
+fn main() {
+    let lm = LoveMachine::new(27);
+    println!("Display:   {}", lm);
+    println!("Debug:     {:?}", lm);
+    println!("Octal:     {:o}", lm);
+    println!("LowerHex:  {:x}", lm);
+    println!("UpperHex:  {:X}", lm);
+    println!("Binary:    {:b}", lm);
+}
diff --git a/aufgaben/sheet9/sol3/map.rs b/aufgaben/sheet9/sol3/map.rs
new file mode 100755
index 0000000..142471b
--- /dev/null
+++ b/aufgaben/sheet9/sol3/map.rs
@@ -0,0 +1,15 @@
+
+macro_rules! hash_map {
+    ( $($key:expr => $value:expr ,)* ) => {{
+        let mut map = ::std::collections::HashMap::new();
+        $( map.insert($key, $value); )*
+        map
+    }};
+    ( $($key:expr => $value:expr),* ) => { hash_map!($($key => $value ,)*) };
+}
+
+
+fn main() {
+    let ages = hash_map!{ "Sabine" => 26, "Peter" => 32 };
+    println!("{:#?}", ages);
+}