rollup merge of #20518: nagisa/weighted-bool

[rust.git] / src / librand / lib.rs

diff --git a/src/librand/lib.rs b/src/librand/lib.rs
index bbcd99afdea9331330a1349e565f19964ada79f4..f538e0ade05f5f5e1d32fe442c82a2389dbf7ae9 100644 (file)
--- a/src/librand/lib.rs
+++ b/src/librand/lib.rs
@@ -25,6 +25,7 @@
 
 #![feature(macro_rules, phase, globs)]
 #![feature(unboxed_closures)]
+#![feature(associated_types)]
 #![no_std]
 #![experimental]
 
@@ -74,7 +75,7 @@ pub trait Rng : Sized {
     /// these two methods. Similarly to `next_u32`, this rarely needs
     /// to be called directly, prefer `r.gen()` to `r.next_u64()`.
     fn next_u64(&mut self) -> u64 {
-        (self.next_u32() as u64 << 32) | (self.next_u32() as u64)
+        ((self.next_u32() as u64) << 32) | (self.next_u32() as u64)
     }
 
     /// Return the next random f32 selected from the half-open
@@ -242,7 +243,7 @@ fn gen_range<T: PartialOrd + SampleRange>(&mut self, low: T, high: T) -> T {
     /// println!("{}", rng.gen_weighted_bool(3));
     /// ```
     fn gen_weighted_bool(&mut self, n: uint) -> bool {
-        n == 0 || self.gen_range(0, n) == 0
+        n <= 1 || self.gen_range(0, n) == 0
     }
 
     /// Return an iterator of random characters from the set A-Z,a-z,0-9.
@@ -268,7 +269,7 @@ fn gen_ascii_chars<'a>(&'a mut self) -> AsciiGenerator<'a, Self> {
     /// ```
     /// use std::rand::{thread_rng, Rng};
     ///
-    /// let choices = [1i, 2, 4, 8, 16, 32];
+    /// let choices = [1, 2, 4, 8, 16, 32];
     /// let mut rng = thread_rng();
     /// println!("{}", rng.choose(&choices));
     /// # // replace with slicing syntax when it's stable!
@@ -290,7 +291,7 @@ fn choose<'a, T>(&mut self, values: &'a [T]) -> Option<&'a T> {
     /// use std::rand::{thread_rng, Rng};
     ///
     /// let mut rng = thread_rng();
-    /// let mut y = [1i, 2, 3];
+    /// let mut y = [1, 2, 3];
     /// rng.shuffle(&mut y);
     /// println!("{}", y.as_slice());
     /// rng.shuffle(&mut y);
@@ -314,7 +315,9 @@ pub struct Generator<'a, T, R:'a> {
     rng: &'a mut R,
 }
 
-impl<'a, T: Rand, R: Rng> Iterator<T> for Generator<'a, T, R> {
+impl<'a, T: Rand, R: Rng> Iterator for Generator<'a, T, R> {
+    type Item = T;
+
     fn next(&mut self) -> Option<T> {
         Some(self.rng.gen())
     }
@@ -327,7 +330,9 @@ pub struct AsciiGenerator<'a, R:'a> {
     rng: &'a mut R,
 }
 
-impl<'a, R: Rng> Iterator<char> for AsciiGenerator<'a, R> {
+impl<'a, R: Rng> Iterator for AsciiGenerator<'a, R> {
+    type Item = char;
+
     fn next(&mut self) -> Option<char> {
         static GEN_ASCII_STR_CHARSET: &'static [u8] =
             b"ABCDEFGHIJKLMNOPQRSTUVWXYZ\
@@ -380,6 +385,7 @@ pub trait SeedableRng<Seed>: Rng {
 /// RNGs"](http://www.jstatsoft.org/v08/i14/paper). *Journal of
 /// Statistical Software*. Vol. 8 (Issue 14).
 #[allow(missing_copy_implementations)]
+#[deriving(Clone)]
 pub struct XorShiftRng {
     x: u32,
     y: u32,
@@ -387,17 +393,6 @@ pub struct XorShiftRng {
     w: u32,
 }
 
-impl Clone for XorShiftRng {
-    fn clone(&self) -> XorShiftRng {
-        XorShiftRng {
-            x: self.x,
-            y: self.y,
-            z: self.z,
-            w: self.w,
-        }
-    }
-}
-
 impl XorShiftRng {
     /// Creates a new XorShiftRng instance which is not seeded.
     ///
@@ -502,6 +497,7 @@ fn rand<R: Rng>(rng: &mut R) -> XorShiftRng {
 #[cfg(not(test))]
 mod std {
     pub use core::{option, fmt}; // panic!()
+    pub use core::clone; // derive Clone
     pub use core::kinds;
 }