See the section of the tutorial on for and do - they are desugared to use
functions of that sort (i.e., the body is a closure which is the last parameter
of the function used).
The following code compiles:
fn main() {
for 5.timesi |i| {
if i % 2 == 0 {
loop;
}
io::println(i.to_str());
}
for int::range(0,10) |i| {
io::println(i.to_str());
if i > 5 {
break;
}
}
}
And produces:
1
3
0
1
2
3
4
5
6
On Oct 24, 2012, at 1:28 PM, Dave Halperin wrote:
> Not exactly, those don't have the right signature to be used with a for loop,
> they just take a function. You wouldn't be able to use break or continue
> with them.
>
> On Wed, Oct 24, 2012 at 12:20 PM, Daniel Patterson <[email protected]> wrote:
> See times, timesi (implemented for uint and int), and int::range (i.e., these
> all already exist)
>
> On Oct 24, 2012, at 11:23 AM, Dave Halperin wrote:
>
>> Python doesn't have c style for loops and the way you'd do this is use
>> xrange to create an iterator over a range of numbers, then use a high level
>> for loop. This seems like the cleanest solution for rust to me.
>> Psuedo-code:
>>
>> for range(start, end) |i| {
>> char c = buf[i];
>> ...
>> if (c == uninteresting) {
>> continue;
>> }
>> ...
>> }
>>
>> Seems like range and some related functions should be considered for the
>> standard library to support this style.
>>
>> On Wed, Oct 24, 2012 at 8:58 AM, Chris Double <[email protected]>
>> wrote:
>> On Wed, Oct 24, 2012 at 8:19 PM, Henri Sivonen <[email protected]> wrote:
>> > Looping over a part of an array by index and moving on immediately
>> > when a “not interested” condition matches.
>> >
>> > Stuff like
>> > for (int i = start; i < end; i++) {
>> > char c = buf[i];
>> > ...
>> > if (c == uninteresting) {
>> > continue;
>> > }
>> > ...
>> > }
>>
>> You might be able to bend macros into something you want. For example:
>>
>> macro_rules! my_loop(
>> ($cond:expr, $inc:expr, $body:expr) => {
>> while $cond {
>> while $cond {
>> $body;
>> $inc;
>> }
>> $inc;
>> }
>> };
>> )
>>
>> fn main () {
>> io::println("hello");
>> let mut i = 0;
>> my_loop!(i < 10, i += 1, {
>> if i < 5 { break; }
>> io::println("foo");
>> })
>> }
>>
>> Here 'break' inside the macro is your 'continue' and in the example "i
>> < 5" is the uninteresting check. I don't know how, in rust, to change
>> all uses of some_string into "($inc; loop)" but if you can you can do
>> better than this example.
>>
>> Chris.
>> --
>> http://www.bluishcoder.co.nz
>> _______________________________________________
>> Rust-dev mailing list
>> [email protected]
>> https://mail.mozilla.org/listinfo/rust-dev
>>
>> _______________________________________________
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>> https://mail.mozilla.org/listinfo/rust-dev
>
>
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