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// xfail-fast
#[legacy_modes];
// A trait for objects that can be used to do an if-then-else
// (No actual need for this to be static, but it is a simple test.)
trait bool_like {
static fn select<A>(b: self, +x1: A, +x2: A) -> A;
}
fn andand<T: bool_like Copy>(x1: T, x2: T) -> T {
select(x1, x2, x1)
}
impl bool: bool_like {
static fn select<A>(&&b: bool, +x1: A, +x2: A) -> A {
if b { x1 } else { x2 }
}
}
impl int: bool_like {
static fn select<A>(&&b: int, +x1: A, +x2: A) -> A {
if b != 0 { x1 } else { x2 }
}
}
// A trait for sequences that can be constructed imperatively.
trait buildable<A> {
static pure fn build_sized(size: uint,
builder: fn(push: pure fn(+v: A))) -> self;
}
impl<A> @[A]: buildable<A> {
#[inline(always)]
static pure fn build_sized(size: uint,
builder: fn(push: pure fn(+v: A))) -> @[A] {
at_vec::build_sized(size, builder)
}
}
impl<A> ~[A]: buildable<A> {
#[inline(always)]
static pure fn build_sized(size: uint,
builder: fn(push: pure fn(+v: A))) -> ~[A] {
vec::build_sized(size, builder)
}
}
#[inline(always)]
pure fn build<A, B: buildable<A>>(builder: fn(push: pure fn(+v: A))) -> B {
build_sized(4, builder)
}
/// Apply a function to each element of an iterable and return the results
fn map<T, IT: BaseIter<T>, U, BU: buildable<U>>
(v: IT, f: fn(T) -> U) -> BU {
do build |push| {
for v.each() |elem| {
push(f(*elem));
}
}
}
fn seq_range<BT: buildable<int>>(lo: uint, hi: uint) -> BT {
do build_sized(hi-lo) |push| {
for uint::range(lo, hi) |i| {
push(i as int);
}
}
}
fn main() {
let v: @[int] = seq_range(0, 10);
assert v == @[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
let v: @[int] = map(&[1,2,3], |x| 1+x);
assert v == @[2, 3, 4];
let v: ~[int] = map(&[1,2,3], |x| 1+x);
assert v == ~[2, 3, 4];
assert select(true, 9, 14) == 9;
assert !andand(true, false);
assert andand(7, 12) == 12;
assert andand(0, 12) == 0;
}
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