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// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std::vec;
// Check usage and precedence of block arguments in expressions:
pub fn main() {
let v = ~[-1f, 0f, 1f, 2f, 3f];
// Statement form does not require parentheses:
for v.iter().advance |i| {
info!("%?", *i);
}
// Usable at all:
let mut any_negative = do v.iter().any_ |e| { e.is_negative() };
assert!(any_negative);
// Higher precedence than assignments:
any_negative = do v.iter().any_ |e| { e.is_negative() };
assert!(any_negative);
// Higher precedence than unary operations:
let abs_v = do v.iter().transform |e| { e.abs() }.collect::<~[float]>();
assert!(do abs_v.iter().all |e| { e.is_positive() });
assert!(!do abs_v.iter().any_ |e| { e.is_negative() });
// Usable in funny statement-like forms:
if !do v.iter().any_ |e| { e.is_positive() } {
assert!(false);
}
match do v.iter().all |e| { e.is_negative() } {
true => { fail!("incorrect answer."); }
false => { }
}
match 3 {
_ if do v.iter().any_ |e| { e.is_negative() } => {
}
_ => {
fail!("wrong answer.");
}
}
// Lower precedence than binary operations:
let w = do v.iter().fold(0f) |x, y| { x + *y } + 10f;
let y = do v.iter().fold(0f) |x, y| { x + *y } + 10f;
let z = 10f + do v.iter().fold(0f) |x, y| { x + *y };
assert_eq!(w, y);
assert_eq!(y, z);
// In the tail of a block
let w =
if true { do abs_v.iter().any_ |e| { e.is_positive() } }
else { false };
assert!(w);
}
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