libcore: add num::Int::pow() and deprecate num::pow().

src/libcore/num/mod.rs

@@ -37,28 +37,10 @@ pub fn div_rem<T: Div<T, T> + Rem<T, T>>(x: T, y: T) -> (T, T) {
 }
 
 /// Raises a `base` to the power of `exp`, using exponentiation by squaring.
-///
-/// # Example
-///
-/// ```rust
-/// use std::num;
-///
-/// assert_eq!(num::pow(2i, 4), 16);
-/// ```
 #[inline]
-pub fn pow<T: Int>(mut base: T, mut exp: uint) -> T {
- if exp == 1 { base }
- else {
- let mut acc: T = Int::one();
- while exp > 0 {
- if (exp & 1) == 1 {
- acc = acc * base;
- }
- base = base * base;
- exp = exp >> 1;
- }
- acc
- }
+#[deprecated = "Use Int::pow() instead, as in 2i.pow(4)"]
+pub fn pow<T: Int>(base: T, exp: uint) -> T {
+ base.pow(exp)
 }
 
 /// A built-in signed or unsigned integer.
@@ -359,6 +341,29 @@ pub trait Int
  None => Int::max_value(),
  }
  }
+
+ /// Raises self to the power of `exp`, using exponentiation by squaring.
+ ///
+ /// # Example
+ ///
+ /// ```rust
+ /// use std::num::Int;
+ ///
+ /// assert_eq!(2i.pow(4), 16);
+ /// ```
+ #[inline]
+ fn pow(self, mut exp: uint) -> Self {
+ let mut base = self;
+ let mut acc: Self = Int::one();
+ while exp > 0 {
+ if (exp & 1) == 1 {
+ acc = acc * base;
+ }
+ base = base * base;
+ exp /= 2;
+ }
+ acc
+ }
 }
 
 macro_rules! checked_op {

src/libstd/num/mod.rs

@@ -757,7 +757,7 @@ mod tests {
  }
  macro_rules! assert_pow(
  (($num:expr, $exp:expr) => $expected:expr) => {{
- let result = pow($num, $exp);
+ let result = $num.pow($exp);
  assert_eq!(result, $expected);
  assert_eq!(result, naive_pow($num, $exp));
  }}
@@ -775,12 +775,12 @@ mod tests {
 mod bench {
  extern crate test;
  use self::test::Bencher;
- use num;
+ use num::Int;
  use prelude::*;
 
  #[bench]
  fn bench_pow_function(b: &mut Bencher) {
  let v = Vec::from_fn(1024u, |n| n);
- b.iter(|| {v.iter().fold(0u, |old, new| num::pow(old, *new));});
+ b.iter(|| {v.iter().fold(0u, |old, new| old.pow(*new));});
  }
 }

src/test/bench/shootout-binarytrees.rs

@@ -93,8 +93,8 @@ fn main() {
  let long_lived_tree = bottom_up_tree(&long_lived_arena, 0, max_depth);
 
  let mut messages = range_step(min_depth, max_depth + 1, 2).map(|depth| {
- use std::num::pow;
- let iterations = pow(2i, (max_depth - depth + min_depth) as uint);
+ use std::num::Int;
+ let iterations = 2i.pow((max_depth - depth + min_depth) as uint);
  Future::spawn(proc() {
  let mut chk = 0;
  for i in range(1, iterations + 1) {

src/test/compile-fail/lint-dead-code-4.rs

@@ -14,7 +14,7 @@
 
 extern crate libc;
 
-use std::num;
+use std::num::Int;
 
 struct Foo {
  x: uint,
@@ -23,7 +23,7 @@ struct Foo {
 }
 
 fn field_read(f: Foo) -> uint {
- num::pow(f.x, 2)
+ f.x.pow(2)
 }
 
 enum XYZ {