Add benchmark

README.md

+Benchmarks against a straight loop
+----------------------------------
+
+$ lscpu | grep "Model name"
+Model name:            Intel(R) Core(TM) i5-5200U CPU @ 2.20GHz
+$ cargo bench
+test bench_oddness      ... bench:     398,832 ns/iter (+/- 261,575)
+test bench_oddness_loop ... bench:           2 ns/iter (+/- 0)

benches/bench.rs

+#![feature(test)]
+extern crate tramp;
+extern crate test;
+
+use tramp::oddness as oddness;
+use test::Bencher;
+
+#[bench]
+fn bench_oddness(b: &mut Bencher) {
+    let mut val : u128 = 1000;
+    b.iter(|| {oddness::is_even(val); val += 1;});
+}
+
+#[bench]
+fn bench_oddness_loop(b: &mut Bencher) {
+    let mut val : u128 = 1000;
+    b.iter(|| {oddness::is_even_loop(val); val += 1;});
+}

src/lib.rs

@@ -180,3 +180,5 @@ macro_rules! rec_ret {
         return $crate::BorrowRec::Ret($val);
     };
 }
+
+pub mod oddness;

src/oddness/mod.rs

+use super::{Rec, tramp};
+    fn is_even_rec(x: u128) -> Rec<bool> {
+        if x > 0 {
+            rec_call!(is_odd_rec(x - 1))
+        } else {
+            rec_ret!(true)
+        }
+    }
+
+    fn is_odd_rec(x: u128) -> Rec<bool> {
+        if x > 0 {
+            rec_call!(is_even_rec(x - 1))
+        } else {
+            rec_ret!(false)
+        }
+    }
+
+    pub fn is_even(x: u128) -> bool {
+        tramp(is_even_rec(x))
+    }
+
+    pub fn is_odd(x: u128) -> bool {
+        tramp(is_odd_rec(x))
+    }
+
+    pub fn is_even_loop(x: u128) -> bool {
+        let mut i: u128 = x;
+        let mut even = true;
+        while i > 0 {
+            i = i - 1;
+            even = !even;
+        }
+        even
+    }
+
+    pub fn is_odd_loop(x: u128) -> bool {
+        !is_even_loop(x)
+    }

tests/mutual.rs

-#[macro_use]
 extern crate tramp;
-
-// Not the greatest way of computing "is even" or "is odd".
-mod oddness {
-    use tramp::{tramp, Rec};
-
-    fn is_even_rec(x: u128) -> Rec<bool> {
-        if x > 0 {
-            rec_call!(is_odd_rec(x - 1))
-        } else {
-            rec_ret!(true)
-        }
-    }
-
-    fn is_odd_rec(x: u128) -> Rec<bool> {
-        if x > 0 {
-            rec_call!(is_even_rec(x - 1))
-        } else {
-            rec_ret!(false)
-        }
-    }
-
-    pub fn is_even(x: u128) -> bool {
-        tramp(is_even_rec(x))
-    }
-
-    pub fn is_odd(x: u128) -> bool {
-        tramp(is_odd_rec(x))
-    }
-}
+use tramp::oddness;
 
 #[test]
 fn test_oddness() {