src/test/run-pass/while-let.rs

   1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11
  12 #![feature(binary_heap_extras)]
  13
  14 use std::collections::BinaryHeap;
  15
  16 fn make_pq() -> BinaryHeap<isize> {
  17     BinaryHeap::from(vec![1,2,3])
  18 }
  19
  20 pub fn main() {
  21     let mut pq = make_pq();
  22     let mut sum = 0;
  23     while let Some(x) = pq.pop() {
  24         sum += x;
  25     }
  26     assert_eq!(sum, 6);
  27
  28     pq = make_pq();
  29     sum = 0;
  30     'a: while let Some(x) = pq.pop() {
  31         sum += x;
  32         if x == 2 {
  33             break 'a;
  34         }
  35     }
  36     assert_eq!(sum, 5);
  37
  38     pq = make_pq();
  39     sum = 0;
  40     'a: while let Some(x) = pq.pop() {
  41         if x == 3 {
  42             continue 'a;
  43         }
  44         sum += x;
  45     }
  46     assert_eq!(sum, 3);
  47
  48     let mut pq1 = make_pq();
  49     sum = 0;
  50     while let Some(x) = pq1.pop() {
  51         let mut pq2 = make_pq();
  52         while let Some(y) = pq2.pop() {
  53             sum += x * y;
  54         }
  55     }
  56     assert_eq!(sum, 6 + 12 + 18);
  57 }