rolled up various changes

Author: BartMassey

debug-macro.rs

@@ -3,13 +3,27 @@ const DEBUG: bool = true;
 
 #[allow(unused)]
 macro_rules! debug {
+    ($msg:literal) => {
+        if DEBUG {
+            eprintln!("{}", $msg as &'static str);
+        }
+    };
     ($msg:literal, $x:expr) => {
         if DEBUG {
             eprintln!("{}: {:?}", $msg as &'static str, $x);
         }
     };
 }
 
+#[allow(unused)]
+fn bad_fib(n: u64) -> u64 {
+    match n {
+        i@(0|1) => i,
+        n => bad_fib(n - 1) + bad_fib(n - 2),
+    }
+}
+
 fn main() {
-    debug!("running", Some(5));
+    debug!("running");
+    debug!("running", "yep");
 }

histogram.rs

@@ -11,7 +11,7 @@ use std::io::Read;
 use std::iter::FromIterator;
 
 #[derive(Clone, Debug)]
-struct Histogram<T: Hash + Eq>(HashMap<T, usize>);
+struct Histogram<T: Hash + Eq, u64>(HashMap<T, C>);
 
 impl<T: Hash + Eq> Histogram<T> {
     fn histogram<I>(values: I) -> Self
@@ -27,9 +27,9 @@ impl<T: Hash + Eq> Histogram<T> {
 }
 
 impl<T: Hash + Eq + Ord> Histogram<T> {
-    fn graph<'a>(&'a self) -> Vec<(&'a T, usize)> {
+    fn graph<'a>(&'a self) -> Vec<(&'a T, u64)> {
         let Histogram(h) = self;
-        let mut result: Vec<(&T, usize)> =
+        let mut result: Vec<(&T, u64)> =
             h.iter().map(|(k, v)| (k, *v)).collect();
         result.sort();
         result

macro-tt.rs

@@ -1,5 +1,5 @@
 macro_rules! reargument {
-    ($x:tt ! ( $($_:tt),* )) => ($x!("huh"))
+    ($x:ident ! ( $($_:tt),* )) => ($x!("huh"))
 }
 
 fn main() {

square-macro.rs

@@ -1,12 +1,11 @@
 macro_rules! square {
     ($s:expr) => {{
-        let n = $s;
-        n * n
+        ($s) * ($s)
     }};
 }
 
 fn main() {
-    let mut n = 3;
+    let mut n = 3_u8;
     println!("3**2={}", square!(n));
     println!("4**2={}", square!({n += 1; n}));
 }